Westinghouse Reactor Protection System Unavailability, 1984--1995
Eide, Steven Arvid; Calley, Michael Brennan; Gentillon, Cynthia Ann; Wierman, Thomas Edward; Rasmuson, D.; Marksberry, D.
1999-08-01T23:59:59.000Z
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
Westinghouse Reactor Protection System Unavailability, 1984-1995
C. D. Gentillon; D. Marksberry (USNRC); D. Rasmuson; M. B. Calley; S. A. Eide; T. Wierman (INEEL)
1999-08-01T23:59:59.000Z
An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.
Cathodic protection in oilfield brine
Turnipseed, S.P. (Chevron U.S.A. Inc., Houston, TX (US))
1991-12-01T23:59:59.000Z
In this paper the use of cathodic protection (CP) to mitigate internal and corrosion-related failures that occur in the produced brine phase of oilfield tanks and production vessels is discussed. Unique considerations covered include brine properties, CP system selection, installation details, monitoring, and coatings.
CHEMISTRY OF SILICA IN CERRO PRIETO BRINES
Weres, O.
2012-01-01T23:59:59.000Z
chemistry of silica in Cerro Prieto brine may profitably be14 mg·l-1 AND SYNTHFTIC CERRO PRIETO BRINES High Ca We112Q.by the CFE Laboratory at Cerro Prieto and kindly provided to
Brining studies at Pepper Products Inc.
Okoro, John Daniel
1988-01-01T23:59:59.000Z
of Department) A. B. Childers (Member) V. E. Sweat (Member) December 1988 Abstract Optimum brining conditions, causes of secondary fermentation, and salt fluctuation were investigated. Jalapeno peppers held in brine solution undergo lactic acid... fermentation, controlled by level of acidification and concentration of salt. Only brining at 7. 5% NaCl, with no added acetic acid, resulted in loss of all fermentable sugars. However, salt concentration fluctuated widely in this sample. Brining in 25...
Improved Water Flooding through Injection Brine Modification
Robertson, Eric Partridge; Thomas, Charles Phillip; Morrow, Norman; (U of Wyoming)
2003-01-01T23:59:59.000Z
Crude oil/brine/rock interactions can lead to large variations in the displacement efficiency of waterflooding, by far the most widely applied method of improved oil recovery. Laboratory waterflood tests show that injection of dilute brine can increase oil recovery. Numerous fields in the Powder River basin have been waterflooded using low salinity brine (about 500 ppm) from the Madison limestone or Fox Hills sandstone. Although many uncertainties arise in the interpretation and comparison of field production data, injection of low salinity brine appears to give higher recovery compared to brine of moderate salinity (about 7,000 ppm). Laboratory studies of the effect of brine composition on oil recovery cover a wide range of rock types and crude oils. Oil recovery increases using low salinity brine as the injection water ranged from a low of no notable increase to as much as 37.0% depending on the system being studied. Recovery increases using low salinity brine after establishing residual oil saturation (tertiary mode) ranged from no significant increase to 6.0%. Tests with two sets of reservoir cores and crude oil indicated slight improvement in recovery for low salinity brine. Crude oil type and rock type (particularly the presence and distribution of kaolinite) both play a dominant role in the effect that brine composition has on waterflood oil recovery.
Development Operations Hypersaline Geothermal Brine Utilization...
Hypersaline Geothermal Brine Utilization Imperial County, California Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Development Operations Hypersaline...
Chemistry of Silica in Cerro Prieto Brines
Weres, Oleh
2012-01-01T23:59:59.000Z
LBL-10166 CERRO-PRIETO-12 XICAN-AMERICANCOOPERATIVE' PROGRAM T THE CERRO PRIETO GEOTHERMAL FIELD ICHEMISTRY OF SILICA IN CERRO PRIETO BRINES Oleh Weres Leon
Chemistry of Silica in Cerro Prieto Brines
Weres, O.
2010-01-01T23:59:59.000Z
LBL-10166 CERRO-PRIETO-12 XICAN-AMERICANCOOPERATIVE' PROGRAM T THE CERRO PRIETO GEOTHERMAL FIELD ICHEMISTRY OF SILICA IN CERRO PRIETO BRINES Oleh Weres Leon
THE MECHANISM OF INTRAGRANULAR MIGRATION OF BRINE INCLUSIONS IN SALT
Machiels, A.J.
2010-01-01T23:59:59.000Z
of Brine Inclusions in a Salt Repository", ORM. -5526 (JulyOF BRINE INCLUSIONS IN SALT A.J. Machiels, S. Yagnik, D.R.OF BRINE INCLUSIONS IN SALT by A.J. Machiels S. Yagnik D.R.
Biomass production from inland brines
Reach, C.D. Jr.
1985-01-01T23:59:59.000Z
The feasibility of utilizing inland saline waters to produce biomass through the application of marine aquaculture was investigated. From available data, the diatom Phaeodactylum tricornutum and the crustacea Artemia salina were selected as the experimental marine organisms. The proposed diatom served to establish primary productivity and concurrently provide a food source for the herbivorus crustacea. The objective of the first phase research was to investigate the ability of P. tricornutum and A. salina to survive in the inland saline environment. Clarified activated sludge and anaerobic digester effluents were evaluated as nutrient sources for the diatom cultures. Experimental results indicated that diatom and crustacea growth in the inland brine was equivalent to control cultures utilizing seawater. Wastewater effluents were successful as nutrient sources for the diatom cultures. Bioassay experiments conducted with petroleum related brines yielded mixed results respect to the survival and growth of the P. tricornutum and A. salina organisms. A second series of experiments involved cholornaphthalene, chlorophenanthene, and chlorophenanthrene, and chloroanthracene as the experimental hydrocarbons. Results of the diatom studies show chloroanthracene to induce toxic effects at a concentration of 500 ug/L. Artemia studies showed no acutely toxic effects relative to the test hydrocarbons at 50 and 100 ug/L.
Brine flow in heated geologic salt.
Kuhlman, Kristopher L.; Malama, Bwalya
2013-03-01T23:59:59.000Z
This report is a summary of the physical processes, primary governing equations, solution approaches, and historic testing related to brine migration in geologic salt. Although most information presented in this report is not new, we synthesize a large amount of material scattered across dozens of laboratory reports, journal papers, conference proceedings, and textbooks. We present a mathematical description of the governing brine flow mechanisms in geologic salt. We outline the general coupled thermal, multi-phase hydrologic, and mechanical processes. We derive these processes' governing equations, which can be used to predict brine flow. These equations are valid under a wide variety of conditions applicable to radioactive waste disposal in rooms and boreholes excavated into geologic salt.
THERMAL GRADIENT MIGRATION OF BRINE INCLUSIONS IN SALT
Yagnik, S.K.
2010-01-01T23:59:59.000Z
OF BRINE INCLUSIONS IN SALT Suresh K. Yagnik February 1982 TOF BRINE INCLUSIONS IN SALT by Suresh K. Yagnik Materialsb u i l t in future. The salt deposits, however, are known
Portable brine evaporator unit, process, and system
Hart, Paul John (Indiana, PA); Miller, Bruce G. (State College, PA); Wincek, Ronald T. (State College, PA); Decker, Glenn E. (Bellefonte, PA); Johnson, David K. (Port Matilda, PA)
2009-04-07T23:59:59.000Z
The present invention discloses a comprehensive, efficient, and cost effective portable evaporator unit, method, and system for the treatment of brine. The evaporator unit, method, and system require a pretreatment process that removes heavy metals, crude oil, and other contaminates in preparation for the evaporator unit. The pretreatment and the evaporator unit, method, and system process metals and brine at the site where they are generated (the well site). Thus, saving significant money to producers who can avoid present and future increases in transportation costs.
Batteries from Brine | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The FutureComments fromofBatteries from Brine Batteries from Brine March 31, 2014
Biochemical processes for geothermal brine treatment
Premuzic, E.T.; Lin, M.S.; Bohenek, M.; Joshi-Tope, G.; Zhou, W.; Shelenkova, L.; Wilke, R.
1998-08-01T23:59:59.000Z
As part of the DOE Geothermal Energy Program, BNL`s Advanced Biochemical Processes for Geothermal Brines (ABPGB) project is aimed at the development of cost-efficient and environmentally acceptable technologies for the disposal of geothermal wastes. Extensive chemical studies of high and low salinity brines and precipitates have indicated that in addition to trace quantities of regulated substances, e.g., toxic metals such as arsenic and mercury, there are significant concentrations of valuable metals, including gold, silver and platinum. Further chemical and physical studies of the silica product have also shown that the produced silica is a valuable material with commercial potential. A combined biochemical and chemical technology is being developed which (1) solubilizes, separates, and removes environmentally regulated constituents in geothermal precipitates and brines, (2) generates an amorphous silica product which may be used as feedstock for the production of revenue generating materials, (3) recover economically valuable trace metals and salts. Geothermal power resources which utilize low salinity brines and use the Stretford process for hydrogen sulfide abatement generate a contaminated sulfur cake. Combined technology converts such sulfur to a commercial grade sulfur, suitable for agricultural use. The R and D activities at BNL are conducted jointly with industrial parties in an effort focused on field applications.
BIOCHEMICAL PROCESSES FOR GEOTHERMAL BRINE TREATMENT
PREMUZIC,E.T.; LIN,M.S.; BOHENEK,M.; JOSHI-TOPE,G.; ZHOU,W.; SHELENKOVA,L.; WILKE,R.
1998-09-20T23:59:59.000Z
As part of the DOE Geothermal Energy Program, BNL's Advanced Biochemical Processes for Geothermal Brines (ABPGB) project is aimed at the development of cost-efficient and environmentally acceptable technologies for the disposal of geothermal wastes. Extensive chemical studies of high and low salinity brines and precipitates have indicated that in addition to trace quantities of regulated substances, e.g., toxic metals such as arsenic and mercury, there are significant concentrations of valuable metals, including gold, silver and platinum. Further chemical and physical studies of the silica product have also shown that the produced silica is a valuable material with commercial potential. A combined biochemical and chemical technology is being developed which (1) solubilizes, separates, and removes environmentally regulated constituents in geothermal precipitates and brines (2) generates an amorphous silica product which may be used as feedstock for the production of revenue generating materials, (3) recover economically valuable trace metals and salts. Geothermal power resources which utilize low salinity brines and use the Stretford process for hydrogen sulfide abatement generate a contaminated sulfur cake. Combined technology converts such sulfur to a commercial grade sulfur, suitable for agricultural use. The R and D activities at BNL are conducted jointly with industrial parties in an effort focused on field applications.
Bachas, C.
1986-03-01T23:59:59.000Z
This is an elementary introduction to the classical and quantum mechanics of a single bosonic string, and to some aspects of its supersymmetric and heterotic extensions. 22 refs.
Radionuclide transport in sandstones with WIPP brine
Weed, H.C.; Bazan, F.; Fontanilla, J.; Garrison, J.; Rego, J.; Winslow, A.M.
1981-02-01T23:59:59.000Z
Retardation factors (R) have been measured for the transport of /sup 3/H, /sup 95m/Tc, and /sup 85/Sr in WIPP brine using St. Peter, Berea, Kayenta, and San Felipe sandstone cores. If tritium is assumed to have R=1, /sup 95m/Tc has R=1.0 to 1.3 and therefore is essentially not retarded. Strontium-85 has R = 1.0 to 1.3 on St. Peter, Berea, and Kayenta, but R=3 on San Felipe. This is attributed to sorption on the matrix material of San Felipe, which has 45 volume % matrix compared with 1 to 10 volume % for the others. Retardation factors (R/sub s/) for /sup 85/Sr calculated from static sorption measurements are unity for all the sandstones. Therefore, the static and transport results for /sup 85/Sr disagree in the case of San Felipe, but agree for St. Peter, Berea, and Kayenta.
Geochemistry of Aluminum in High Temperature Brines
Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.
1999-05-18T23:59:59.000Z
The objective ofthis research is to provide quantitative data on the equilibrium and thermodynamic properties of aluminum minerals required to model changes in permeability and brine chemistry associated with fluid/rock interactions in the recharge, reservoir, and discharge zones of active geothermal systems. This requires a precise knowledge of the thermodynamics and speciation of aluminum in aqueous brines, spanning the temperature and fluid composition rangesencountered in active systems. The empirical and semi-empirical treatments of the solubility/hydrolysis experimental results on single aluminum mineral phases form the basis for the ultimate investigation of the behavior of complex aluminosilicate minerals. The principal objective in FY 1998 was to complete the solubility measurements on boehmite (AIOOH) inNaC1 media( 1 .O and 5.0 molal ionic strength, IOO-250°C). However, additional measurements were also made on boehmite solubility in pure NaOH solutions in order to bolster the database for fitting in-house isopiestic data on this system. Preliminary kinetic Measurements of the dissolution/precipitation of boehmite was also carried out, although these were also not planned in the earlier objective. The 1999 objectives are to incorporate these treatments into existing codes used by the geothermal industry to predict the chemistry ofthe reservoirs; these calculations will be tested for reliability against our laboratory results and field observations. Moreover, based on the success of the experimental methods developed in this program, we intend to use our unique high temperature pH easurement capabilities to make kinetic and equilibrium studies of pH-dependent aluminosilicate transformation reactions and other pH-dependent heterogeneous reactions.
Brine-in-crude-oil emulsions at the Strategic Petroleum Reserve.
Nemer, Martin B.; Lord, David L.; MacDonald, Terry L.
2013-10-01T23:59:59.000Z
Metastable water-in-crude-oil emulsion formation could occur in a Strategic Petroleum Reserve (SPR) cavern if water were to flow into the crude-oil layer at a sufficient rate. Such a situation could arise during a drawdown from a cavern with a broken-hanging brine string. A high asphaltene content (> 1.5 wt %) of the crude oil provides the strongest predictor of whether a metastable water-in-crude-oil emulsion will form. However there are many crude oils with an asphaltene content > 1.5 wt % that don't form stable emulsions, but few with a low asphaltene content that do form stable emulsions. Most of the oils that form stable emulsions are %E2%80%9Csour%E2%80%9D by SPR standards indicating they contain total sulfur > 0.50 wt %.
Origin and geochemical evolution of the Michigan basin brine
Wilson, T.P.
1989-01-01T23:59:59.000Z
Chemical and isotopic data were collected on 126 oil field brine samples and were used to investigate the origin and geochemical evolution of water in 8 geologic formations in the Michigan basin. Two groups of brine are found in the basin, the Na-Ca-Cl brine in the upper Devonian formations, and Ca-Na-Cl brine from the lower Devonian and Silurian aged formations. Water in the upper Devonian Berea, Traverse, and Dundee formations originated from seawater concentrated into halite facies. This brine evolved by halite precipitation, dolomitization, aluminosilicate reactions, and the removal of SO{sub 4} by bacterial action or by CaSO{sub 4} precipitation. The stable isotopic composition (D, O) is thought to represent dilution of evapo-concentrated seawater by meteoric water. Water in the lower Devonian Richfield, Detroit River Group, and Niagara-Salina formations is very saline Ca-Na-Cl brine. Cl/Br suggest it originated from seawater concentrated through the halite and into the MgSO{sub 4} salt facies, with an origin linked to the Silurian and Devonian salt deposits. Dolomitization and halite precipitation increased the Ca/Na, aluminosilicate reactions removed K, and bacterial action or CaSO{sub 4} precipitation removed SO{sub 4} from this brine. Water chemistry in the Ordovician Trenton-Black River formations indicates dilution of evapo-concentrated seawater by fresh or seawater. Possible saline end-members include Ordovician seawater, present-day upper Devonian brine, or Ca-Cl brine from the deeper areas in the basin.
The feasibility of deep well injection for brine disposal
Spongberg, Martin Edward
1994-01-01T23:59:59.000Z
feasibility. The methodology is utilized to make a preliminary evaluation of a proposed brine injection project in the Dove Creek area of King and Stonewall Counties, North Central Texas. Four known deep aquifers are modeled, using the SWIFT/486 software...
acartia tonsa brine: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
be determined in advance. We estimate the optimal design of an average-sized ice rink, including pipe diameter, depth and brine type (ethylene glycol and ammonia). We also...
G. L. Alberghi
2010-02-19T23:59:59.000Z
We describe a possible realization of the spontaneous baryogenesis mechanism in the context of extra-dimensional string cosmology and specifically in the string gas scenario.
New York at Stoney Brook, State University of
1 Up-Scaling Geochemical Reaction Rates Accompanying Acidic CO2-Saturated Brine Flow in Sandstone models. As a step toward this, network flow models were used to simulate the flow of CO2-saturated brine
Nevada: Geothermal Brine Brings Low-Cost Power with Big Potential...
Nevada: Geothermal Brine Brings Low-Cost Power with Big Potential Nevada: Geothermal Brine Brings Low-Cost Power with Big Potential August 21, 2013 - 12:00am Addthis Utilizing a 1...
Gas Content of Gladys McCall Reservoir Brine A Topical Report
Office of Scientific and Technical Information (OSTI)
gas t o brine ratio. This w i l l result i n cubic feet of methane, ethane, propane, etc. per barrel of brine, Then, the contributions from sample points are added until...
Geochemical evidence for possible natural migration of Marcellus Formation brine to
Geochemical evidence for possible natural migration of Marcellus Formation brine to shallow possible migration of Marcellus brine through naturally occurring pathways. The occurrences of saline water, because of natural hydraulic connections to deeper formations. formation water isotopes Marcellus Shale
Constraints on origin and evolution of Red Sea brines from helium and argon isotopes
Winckler, Gisela
Constraints on origin and evolution of Red Sea brines from helium and argon isotopes Gisela November 2000 Abstract Brines from three depressions along the axis of the Red Sea, the Atlantis II II and the Discovery brines originating from locations in the central Red Sea show 4 He
Don Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth's most saline
Marchant, David R.
Don Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth's most saline lake lineae (RSL), thought to represent seasonal brines, has sparked interest in analogous environments watershed and show that this, together with small amounts of meltwater, are capable of generating brines
Dynamics and storage of brine in mid-ocean ridge hydrothermal systems
Wilcock, William
Dynamics and storage of brine in mid-ocean ridge hydrothermal systems Fabrice J. Fontaine1 and brine phases. Time series of vent temperature and salinity (chlorinity) show that some black-smoker vent below seawater for over a decade, which raises important questions concerning the fate of brines
of brine heterogeneity in modern sedimentary basins (6) imply inefficiency of mixing and the
Boyce, C. Kevin
of brine heterogeneity in modern sedimentary basins (6) imply inefficiency of mixing and the potential for preservation of individual, metal- charged brine reservoirs that could be tapped at some later. The observation that the texturally later brines have higher metal contents is consistent with this model
Brine fluxes from growing sea ice A. J. Wells,1,2
Wettlaufer, John S.
Brine fluxes from growing sea ice A. J. Wells,1,2 J. S. Wettlaufer,1,2,3 and S. A. Orszag2] It is well known that brine drainage from growing sea ice has a controlling influence on its mechanical oceans. When the ice has exceeded a critical thickness the drainage process is dominated by brine
On the Reliability of Numerical Solutions of Brine Transport in Groundwater: Analysis of In ltration
Bergamaschi, Luca
On the Reliability of Numerical Solutions of Brine Transport in Groundwater: Analysis of In#12, brine transport List of symbols c normalized salt concentration c k l value of concentration on triangle:37; p.2 #12; Reliability of Numerical Simulations of Brine Transport in Groundwater 3 equivalent
Accurate Thermodynamic Model for the Calculation of H2S Solubility in Pure Water and Brines
Zhu, Chen
Accurate Thermodynamic Model for the Calculation of H2S Solubility in Pure Water and Brines Zhenhao mineral solubility in H2S saturated brines. An example calculation for galena solubility is given. 1 gasification process.5,6 Sequestration of the gases into geological brine formation is one of the promising
WERE AQUEOUS RIPPLES ON MARS FORMED BY FLOWING BRINES? MICHAEL P. LAMB, JOHN P. GROTZINGER
WERE AQUEOUS RIPPLES ON MARS FORMED BY FLOWING BRINES? MICHAEL P. LAMB, JOHN P. GROTZINGER are not observed. Recent thermodynamic modeling indicates that these brines could have had higher densities (by up whether ripples could have been stable bed forms under flowing Martian brines. To this end, we compiled
Advanced biochemical processes for geothermal brines: Current developments
Premuzic, E.T.; Lin, M.S.; Bohenek, M. [Brookhaven National Lab., Upton, NY (United States). Energy Science and Technology Div.; Bajsarowicz, V. [CET Environmental Services, Inc., Richmond, CA (United States); McCloud, M. [C.E. Holt/California Energy, Pasadena, CA (United States)
1997-07-07T23:59:59.000Z
A research program at Brookhaven National Laboratory (BNL) which deals with the development and application of processes for the treatment of geothermal brines and sludges has led to the identification and design of cost-efficient and environmentally friendly treatment methodology. Initially the primary goal of the processing was to convert geothermal wastes into disposable materials whose chemical composition would satisfy environmental regulations. An expansion of the r and D effort identified a combination of biochemical and chemical processes which became the basis for the development of a technology for the treatment of geothermal brines and sludges. The new technology satisfies environmental regulatory requirements and concurrently converts the geothermal brines and sludges into commercially promising products. Because the chemical composition of geothermal wastes depends on the type of the resource, the emerging technology has to be flexible so that it can be readily modified to suit the needs of a particular type of resource. Recent conceptional designs for the processing of hypersaline and low salinity brines and sludges will be discussed.
Oil production enhancement through a standardized brine treatment. Final report
Adewumi, A.; Watson, R.; Tian, S.; Safargar, S.; Heckman, S.; Drielinger, I.
1995-08-01T23:59:59.000Z
In order to permit the environmentally safe discharge of brines produced from oil wells in Pennsylvania to the surface waters of the Commonwealth and to rapidly brings as many wells as possible into compliance with the law, the Pennsylvania Oil and Gas Association (POGAM) approached the Pennsylvania State University to develop a program designed to demonstrate that a treatment process to meet acceptable discharge conditions and effluent limitations can be standardized for all potential stripper wells brine discharge. After the initial studies, the first phase of this project was initiated. A bench-scale prototype model was developed for conducting experiments in laboratory conditions. The experiments pursued in the laboratory conditions were focused on the removal of ferrous iron from synthetically made brine. Iron was selected as the primary heavy metals for studying the efficiency of the treatment process. The results of a number of experiments in the lab were indicative of the capability of the proposed brine treatment process in the removal of iron. Concurrent with the laboratory experiments, a comprehensive and extensive kinetic study was initiated. This study was necessary to provide the required data base for process modeling. This study included the investigation of the critical pH as well as the rate and order of reactions of the studied elements: aluminum, lead, zinc, and copper. In the second phase of this project, a field-based prototype was developed to evaluate and demonstrate the treatment process effectiveness. These experiments were conducted under various conditions and included the testing on five brines from different locations with various dissolved constituents. The outcome of this research has been a software package, currently based on iron`s reactivity, to be used for design purposes. The developed computer program was refined as far as possible using the results from laboratory and field experiments.
Broussard, Suzanne Rene
1988-01-01T23:59:59.000Z
solution reduced the 41 120 100 0 0 80 E CL CL CV g 60 CL 40 20 ? ~ 0:23, CaCI2. NaCI ? ? & 5:18, Caclz. NaCI ? ? 0 8:15, CaCI2. NaCI 0 4 6 Days on Ice 10 Figure 13-Residual sulfur dioxide on thawed brine frozen shrimp frozen... freezing for two trials. 34 13-Residual sulfur dioxide on thawed brine frozen shrimp frozen in different brine immersion media 41 Figure 14- Black spot development on thawed brine frozen shrimp frozen in different brine immersion media Page 42...
Washington Taylor
2006-06-28T23:59:59.000Z
This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expanding around a fixed choice of space-time background, the theory is in principle background-independent, in the sense that different backgrounds can be realized as different field configurations in the theory. String field theory is the only string formalism developed so far which, in principle, has the potential to systematically address questions involving multiple asymptotically distinct string backgrounds. Thus, although it is not yet well defined as a quantum theory, string field theory may eventually be helpful for understanding questions related to cosmology in string theory.
Nonsingular static global string
A. A. Sen; N. Banerjee
2000-04-12T23:59:59.000Z
A new solution for the spacetime outside the core of a U(1) static global string has been presented which is nonsingular. This is the first example of a nonsingular spacetime around a static global string.}}
Analysis of anions in geological brines using ion chromatography
Merrill, R.M.
1985-03-01T23:59:59.000Z
Ion chromatographic procedures for the determination of the anions bromide, sulfate, nitrite, nitrate, phosphate, and iodide in brine samples have been developed and are described. The techniques have been applied to the analysis of natural brines, and geologic evaporites. Sample matrices varied over a range from 15,000 mg/L to 200,000 mg/L total halogens, nearly all of which is chloride. The analyzed anion concentrations ranged from less than 5 mg/L in the cases of nitrite, nitrate, and phosphate, to 20,000 mg/L in the case of sulfate. A technique for suppressing chloride and sulfate ions to facilitate the analysis of lower concentration anions is presented. Analysis times are typically less than 20 minutes for each procedure and the ion chromatographic results compare well with those obtained using more time consuming classical chemical analyses. 10 references, 14 figures.
Schechter, David S.
44 2 INVESTIGATION OF CRUDE OIL/BRINE/ROCK INTERACTION 2.1 EXPERIMENTAL STUDY OF CRUDE of imbibition or oil production rate, particularly after seven days or more aging time with oil. However in this section and expand the understanding of the interactions of the Spraberry reservoir rock, oil and brine
Jorgensen, D.K.; Kuhns, D.J.; Wiersholm, O.; Miller, T.A.
1993-03-02T23:59:59.000Z
The drill string enclosure consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts. The upper acrylic cylinder is optional based upon the drill string length. The drill string enclosure allows for an efficient drill and sight operation at a hazardous waste site.
Neil. D. Lambert; David Tong
1999-07-13T23:59:59.000Z
We study two-dimensional SQED viewed as the world-volume theory of a D-string in the presence of D5-branes with non-zero background fields that induce attractive forces between the branes. In various approximations, the low-energy dynamics is given by a hyperKahler, or hyperKahler with torsion, massive sigma-model. We demonstrate the existence of kink solutions corresponding to the string interpolating between different D5-branes. Bound states of the D-string with fundamental strings are identified with Q-kinks which, in turn, are identified with dyonic instanton strings on the D5-brane world-volume.
String Amplitudes from Moyal String Field Theory
I. Bars; I. Kishimoto; Y. Matsuo
2002-12-29T23:59:59.000Z
We illustrate a basic framework for analytic computations of Feynman graphs using the Moyal star formulation of string field theory. We present efficient methods of computation based on (a) the monoid algebra in noncommutative space and (b) the conventional Feynman rules in Fourier space. The methods apply equally well to perturbative string states or nonperturbative string states involving D-branes. The ghost sector is formulated using Moyal products with fermionic (b,c) ghosts. We also provide a short account on how the purely cubic theory and/or VSFT proposals may receive some clarification of their midpoint structures in our regularized framework.
A cost-effective statistical screening method to detect oilfield brine contamination
Alyanak, N.; Grace, J.T.; Campbell, M.D. [United Resources International, Houston, TX (United States)
1995-12-01T23:59:59.000Z
A statistical screening method has been developed using Tolerance Limits for barium (Ba{sup +2}) to identify contamination of a fresh-water aquifer by oilfield brines. The method requires an understanding of the local hydrochemistry of oilfield brines, inexpensive, Publicly available hydrochemical data, a single sample analysis from the suspect well and the application of a simple statistical procedure. While this method may not provide absolute evidence of oilfield brine contamination of a fresh-water aquifer, it does identify conditions where brine contamination is a strong probability over other possible sources of chlorides.
and showed that the platform can support a quick development cycle for real-time decision-support algorithms1 Abstract--The unavailability of a flexible system for real- time testing of decision for life-saving interventions and immediate evacuation, and advises on appropriate therapeutic actions [1
Pressure Buildup and Brine Migration During CO2 Storage in Multilayered Aquifers
Zhou, Quanlin
. Introduction Carbon dioxide capture combined with geologic stor- age (CCS) in suitable subsurface formations-6584.2012.00972.x potentially creating far-ranging pressure buildup and brine displacement in deep CO2 storage of resident brine caused by CCS operations require modeling/analysis tools of considerable complexity (Celia
Conservative behavior of uranium vs. salinity in Arctic sea ice and brine Christelle Not a,
Available online 23 December 2011 Keywords: Uranium Salinity Sea ice Brine Seawater Arctic UraniumConservative behavior of uranium vs. salinity in Arctic sea ice and brine Christelle Not a, ,1 disequilibrium The conservative behavior of uranium (U) with respect to salinity in open ocean waters is widely
RIS-M-2260 HEAT GRADIENT INDUCED MIGRATION OF BRINE INCLUSIONS IN ROCK SALT
RISØ-M-2260 HEAT GRADIENT INDUCED MIGRATION OF BRINE INCLUSIONS IN ROCK SALT Mathematical treatment project. Abstract. A mathematical model for the brine migration in rock salt around an infinite line heat source is set up. The tempera- ture field around the time dependent heat source is calculated by use
Hassanizadeh, S. Majid
-concentration-gradient brine displacements in coarse and medium sands S.J. Watson a,1 , D.A. Barry a,1 , R.J. Schotting b,*, S by a brine solution, under either constant head or constant volume flux conditions. The experimental data, significantly less ex- perimental research has been conducted to investigate high-concentration (e.g., brine
PII S0016-7037(01)00901-2 Effect of light and brine shrimp on skeletal 13
Grottoli, Andréa G.
PII S0016-7037(01)00901-2 Effect of light and brine shrimp on skeletal 13 C in the Hawaiian coral, or high concentrations of brine shrimp. Decreases in light from 100% resulted in significant decreases. Increases in brine shrimp concentrations resulted in increased skeletal 13 C levels. This unexpected outcome
Talley, Lynne D.
Dense water formation on the northwestern shelf of the Okhotsk Sea: 1. Direct observations of brine 2004; accepted 21 April 2004; published 1 July 2004. [1] Dense Shelf Water (DSW) formation due to brine this period. The density increase terminated abruptly in late February, while the active brine rejection
Banks, David
PII S0016-7037(01)00579-8 The origin and evolution of base metal mineralising brines are the source of the mineralising fluids. Cl and Br systematics suggest that the brines were formed either cation composition (Na, Ca, K, Mg) of the brines is not consistent solely with evaporation processes
P. F. Gonzalez-Diaz
1995-08-28T23:59:59.000Z
This paper deals with the geometry of supermassive cosmic strings. We have used an approach that enforces the spacetime of cosmic strings to also satisfy the conservation laws of a cylindric gravitational topological defect, that is a spacetime kink. In the simplest case of kink number unity, the entire energy range of supermassive strings becomes then quantized so that only cylindrical defects with linear energy density $G\\mu=1/4$ (critical string) and $G\\mu=1/2$ (extreme string) are allowed to occur in this range. It has been seen that the internal spherical coordinate $\\theta$ of the string metric embedded in an Euclidean three-space also evolves on imaginary values, leading to the creation of a covering shell of broken phase that protects the core with trapped energy, even for $G\\mu=1/2$. Then the conical singularity becomes a removable horizaon singularity. We re-express the extreme string metric in the Finkelstein- McCollum standard form and remove the geodesic incompleteness by using the Kruskal technique. The z=const. sections of the resulting metric are the same as the hemispherical section of the metric of a De Sitter kink. Some physical consequences from these results, including the possibility that the extreme string drives inflation and thermal effects in its core, are also discussed.
Reheating and Cosmic String Production
Chao-Jun Feng; Xian Gao; Miao Li; Wei Song; Yushu Song
2008-01-04T23:59:59.000Z
We compute the string production rate at the end of inflation, using the string spectrum obtained in \\lss in a near-de Sitter space. Our result shows that highly excited strings are hardly produced, thus the simple slow-roll inflation alone does not offer a cosmic string production mechanism.
Twistor Strings and Supergravity
Abou-Zeid, Mohab [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, 1050 Brussels (Belgium)
2007-01-12T23:59:59.000Z
Einstein gravity can be formulated in such a way that it leads to a perturbation theory about an asymmetric weak coupling limit that treats positive and negative helicities differently. The power counting rules for scattering amplitudes then suggest an interpretation in terms of a twistor string theory for gravity, with amplitudes supported on holomorphic curves in twistor space. After reviewing this formulation, I survey the recent construction of a family of new twistor string theories h are free from world-sheet anomalies and give the space-time spectra of Einstein supergravities, with second order field equations instead of the higher derivative conformal supergravities that arose from earlier twistor strings.
Hassan, M.; Vesely, W.E.
1998-01-01T23:59:59.000Z
In this report, we present a screening study to identify environmental stressors for digital instrumentation and control (I&C) systems in a nuclear power plant (NPP) which can be potentially risk-significant, and compare the hardware unavailability of such a system with that of its existing analog counterpart. The stressors evaluated are temperature, humidity, vibration, radiation, electro-magnetic interference (EMI), and smoke. The results of risk-screening for an example plant, subject to some bounding assumptions and based on relative changes in plant risk (core damage frequency impacts of the stressors), indicate that humidity, EMI from lightning, and smoke can be potentially risk-significant. Risk from other sources of EMI could not be evaluated for a lack of data. Risk from temperature appears to be insignificant as that from the assumed levels of vibrations. A comparison of the hardware unavailability of the existing analog Safety Injection Actuation System (SIAS) in the example plant with that of an assumed digital upgrade of the system indicates that system unavailability may be more sensitive to the level of redundancy in elements of the digital system than to the environmental and operational variations involved. The findings of this study can be used to focus activities relating to the regulatory basis for digital I&C upgrades in NPPs, including identification of dominant stressors, data-gathering, equipment qualification, and requirements to limit the effects of environmental stressors. 30 refs., 8 figs., 26 tabs.
Arago C. de; Bazeia, D.; Eboli, O.J.P.; Marques, G.C.
1985-12-15T23:59:59.000Z
We obtain a semiclassical evaluation of the temperature for which the free energy of the strings of spontaneously broken scalar electrodynamics vanishes. We argue that, above this temperature, these objects should play a significant physical role.
Seizing a species : the story of the Great Salt Lake brine shrimp harvest
Wotipka, Samuel Alex
2014-01-01T23:59:59.000Z
In the early 1950s, C.C. "Sparkplug" Sanders began harvesting brine shrimp from Utah's Great Salt Lake. Sanders built up a small business selling their eggs, called "cysts, to aquarium stores across the country. During the ...
Soils and Brine Geochemistry and Mineralogy of Hyperarid Desert Playa, Ouargla Basin,
Ahmad, Sajjad
Soils and Brine Geochemistry and Mineralogy of Hyperarid Desert Playa, Ouargla Basin, Algerian. The chemical and mineralogical specificity of this hyperarid ecosystem has been compared to other areas under
Itzhak, D.; Elias, O. (Ben-Gurion Univ., Beer-Sheva (Israel). Dept. of Materials Engineering)
1994-02-01T23:59:59.000Z
Cylindrical tensile specimens of AISI type 304 (UNS S30400) and type 316 (UNS S31600) stainless steels (SS) were tested under constant-load conditions in 55% lithium bromide (LiBr) heavy brines at temperatures of 120 C and 140 C. Elongation and open-circuit potential (OCP) were recorded during the tensile test. Potentiodynamic polarization measurements were conducted, and the failed surface fractures were examined by scanning electron microscopy. The tested SS were subjected to stress corrosion under the test environments. Sensitivity was affected strongly by pH values. In LiBr brine of pH = 11.6, the passivation processes were more effective than in brine of pH = 6 [approximately] 8. Because of effective passivation behavior in brine of pH = 11.6, lower values of [delta]l[sub 0] were measured, indicating lower dislocation relaxation processes and high resistance to stress corrosion cracking.
New Energy Efficient Method for Cleaning Oilfield Brines with Carbon Dioxide
Little, C. T.; Seibert, A. F.; Bravo, J. L.; Fair, J. R.
1991-01-01T23:59:59.000Z
Water contaminated with hydrocarbons often results during the production of oil. The polluted water, which may be naturally occurring or a result of water or steam flooding operations, must be cleaned before disposal or re-injection. These brines...
Pathogenicity of a pseudomonad bacterium to larvae of penaeid and brine shrimp
Huang, Chu-Liang
1982-01-01T23:59:59.000Z
OF SCIENCE August 1982 Major Subject: Veterinary Microbiology PATHOGENICITY OF A PSEUDOMONAD BACTERIUM TO LARVAE OF PENAEID AND BRINE SHRIMP A Thesis by CHU-LIANG HUANG Approved as to style and content by: (Chairman of Committee) (Member) (Member...) (Member) (Head of Department) August 1982 ABSTRACT Pathogenicity of a Pseudomonad Bacterium to Larvae of Penaeid and Brine Shrimp (August 1982) Chu-Liang Huang, B. S , National Taiwan University Chairman of Advisory Committee: Dr. Donald H. Lewis A...
Study of thermal-gradient-induced migration of brine inclusions in salt. Final report
Olander, D.R.
1984-08-01T23:59:59.000Z
Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed.
Developing a Process for Commercial Silica Production from Geothermal Brines
Bourcier, W; Martin, S; Viani, B; Bruton, C
2001-04-11T23:59:59.000Z
Useful mineral by-products can be produced from geothermal brines. Although silica has many commercial uses, problems remain in producing a marketable product. We are conducting laboratory and modeling studies aimed at optimizing for rubber additive use, the properties of silica precipitates from Salton Sea and Coso-like geothermal fluids, Our goal is to develop a robust technique for producing silicas that have desirable physical and chemical properties for commercial use, while developing a generic understanding of silica precipitation that will allow extraction to be extended to additional fluid types, and to be easily modified to produce new types of marketable silica. Our experiments start with an acidified geothermal fluid similar to those treated by pH modification technology. Silica precipitation is induced by adding base and/or adding Mg or Ca salts to affect the nature of the precipitate. For the analog Salton Sea fluids, adding base alone caused silica to precipitate fairly rapidly. To date, we have characterized precipitates from experiments in which the final pH varied from 4 to 8, where NaOH and Na{sub 2}C0{sub 3} were added as bases, and CaCl{sub 2} and MgCl{sub 2} were added as salts. SEM photos of the silica precipitates from the Salton Sea and Cos0 fluids show that the silica particles are clusters of smaller silica particles down to the resolution of the SEM (about 80-100 nm in diameter). The particle sizes and surface areas of silicas from the Salton Sea and Coso analog brines are similar to the properties of the Degussa silica commonly used as a rubber additive. An evaluation of the strength of the silica-organic bond as tested by dispersion in oil (polybutadiene) was inconclusive. Neither the Degussa materials nor our laboratory precipitates dispersed readily in nor dispersed down to the fundamental particle size. Preliminary NMR data indicates that the Degussa silica has a smaller degree of silica polymerization (a slightly smaller average number of Si-0 bonds per silica tetrahedron) than the synthetic samples, but a comparable degree of hydrogen bonding of the surface silanol sites.
Gittings, Stephen Reed
1983-01-01T23:59:59.000Z
canyon transect were sta- tions R6 and R7, both of which were on top of Cottonwick Rock, ap- proximately 2 m above the canyon floor. Figure 5 (p. 12) shows that salinity and sulfide at these stations were at normal marine levels. Though the total...HARD-BOT1'OM MACROFAUNA OF THE EAST FLOWER GARDEN BRINE SEEP: IMPACT OF A LONG TERM, POINT-SOURCE BRINE DISCHARGE A Thesis by STEPHEN REED GITTINGS Submitted to the Graduate College of Texas A&M University in partial fulfillment...
Recovery of energy from geothermal brine and other hot water sources
Wahl, III, Edward F. (Claremont, CA); Boucher, Frederic B. (San Juan Capistrano, CA)
1981-01-01T23:59:59.000Z
Process and system for recovery of energy from geothermal brines and other hot water sources, by direct contact heat exchange between the brine or hot water, and an immiscible working fluid, e.g. a hydrocarbon such as isobutane, in a heat exchange column, the brine or hot water therein flowing countercurrent to the flow of the working fluid. The column can be operated at subcritical, critical or above the critical pressure of the working fluid. Preferably, the column is provided with a plurality of sieve plates, and the heat exchange process and column, e.g. with respect to the design of such plates, number of plates employed, spacing between plates, area thereof, column diameter, and the like, are designed to achieve maximum throughput of brine or hot water and reduction in temperature differential at the respective stages or plates between the brine or hot water and the working fluid, and so minimize lost work and maximize efficiency, and minimize scale deposition from hot water containing fluid including salts, such as brine. Maximum throughput approximates minimum cost of electricity which can be produced by conversion of the recovered thermal energy to electrical energy.
Numerical simulations of lab-scale brine-water mixing experiments.
Khalil, Imane; Webb, Stephen Walter
2006-10-01T23:59:59.000Z
Laboratory-scale experiments simulating the injection of fresh water into brine in a Strategic Petroleum Reserve (SPR) cavern were performed at Sandia National Laboratories for various conditions of injection rate and small and large injection tube diameters. The computational fluid dynamic (CFD) code FLUENT was used to simulate these experiments to evaluate the predictive capability of FLUENT for brine-water mixing in an SPR cavern. The data-model comparisons show that FLUENT simulations predict the mixing plume depth reasonably well. Predictions of the near-wall brine concentrations compare very well with the experimental data. The simulated time for the mixing plume to reach the vessel wall was underpredicted for the small injection tubes but reasonable for the large injection tubes. The difference in the time to reach the wall is probably due to the three-dimensional nature of the mixing plume as it spreads out at the air-brine or oil-brine interface. The depth of the mixing plume as it spreads out along the interface was within a factor of 2 of the experimental data. The FLUENT simulation results predict the plume mixing accurately, especially the water concentration when the mixing plume reaches the wall. This parameter value is the most significant feature of the mixing process because it will determine the amount of enhanced leaching at the oil-brine interface.
What is Decidable about Strings?
Ganesh, Vijay
2011-02-01T23:59:59.000Z
We prove several decidability and undecidability results for the satisfiability/validity problem of formulas over a language of finite-length strings and integers (interpreted as lengths of strings). The atomic formulas ...
Witten Index and Superconducting Strings
V. K. Oikonomou
2010-01-14T23:59:59.000Z
The Yukawa interaction sector of superstring inspired models that give superconducting strings, can be described in terms of a supersymmetric quantum mechanics algebra. We relate the Witten index of susy quantum mechanics with an index characteristic to superconducting string models.
DeRouen, L.R.; Hann, R.W.; Casserly, D.M.; Giammona, C.; Lascara, V.J. (eds.)
1983-02-01T23:59:59.000Z
The Department of Energy's Strategic Petroleum Reserve Program began discharging brine into the Gulf of Mexico from its West Hackberry site near Cameron, Louisiana in May 1981. The brine originates from underground salt domes being leached with water from the Intracoastal Waterway, making available vast underground storage caverns for crude oil. The effects of brine discharge on aquatic organisms are presented in this volume. The topics covered are: benthos; nekton; phytoplankton; zooplankton; and data management.
Sorption of cesium and strontium from concentrated brines by backfill barrier materials
Winslow, C D
1981-03-01T23:59:59.000Z
The sorption of radionuclides from potentially intruding groundwater at a nuclear waste repository is a major chemical function of backfill barriers. In this study, various materials (including clays, zeolites and an inorganic ion exchanger) were screened for the sorption of the fission products cesium and strontium in concentrated brines. Representative brines A and B for the Waste Isolation Pilot Plant (WIPP), a proposed radioactive waste repository and test facility in bedded salt were used. Sorption properties were quantified using empirical distribution coefficients, k/sub d/. Of the materials examined, sodium titanate had the highest k/sub d/ for the sorption of Sr(II) in both brine A (k/sub d/ = 125 ml/g) and brine B(k/sub d/ = 500 to 600 ml/g). A mordenite-type zeolite was the most effective getter for Cs(I) in brine A (k/sub d = 27 ml/g), while illite yielded the highest k/sub d/ for Cs(I) in brine B (k/sub d/ = 115 ml/g). The relative merit of these k/sub d/ values is evaluated in terms of calculated estimates of breakthrough times for a backfill barrier containing the getter. Results show that a backfill mixture containing these getters is potentially an effective barrier to the migration of Sr(II) and Cs(I), although further study (especially for the sorption of cesium from brine A) is recommended. Initial mechanistic studies revealed competing ion effects which would support an ion exchange mechanism. K/sub d/'s were constant over a Sr(II) concentration range of 10/sup -11/ to 10/sup -5/ M and a Cs(I) concentration range of 10/sup -8/ to 10/sup -5/ M, supporting the choice of a linear sorption isotherm as a model for the results. Constant batch composition was shown to be attained within one week.
Keith Dienes
2010-01-08T23:59:59.000Z
We are currently in the throes of a potentially huge paradigm shift in physics. Motivated by recent developments in string theory and the discovery of the so-called "string landscape", physicists are beginning to question the uniqueness of fundamental theories of physics and the methods by which such theories might be understood and investigated. In this colloquium, I will give a non-technical introduction to the nature of this paradigm shift and how it developed. I will also discuss some of the questions to which it has led, and the nature of the controversies it has spawned.
Kim, Y.
2013-01-01T23:59:59.000Z
accumulation of residual water in pendular structuresAfter drainage, the residual water remained as thick filmsdisplaced brine), the residual water was initially retained
Current balancing for battery strings
Galloway, James H. (New Baltimore, MI)
1985-01-01T23:59:59.000Z
A battery plant is described which features magnetic circuit means for balancing the electrical current flow through a pluraliircuitbattery strings which are connected electrically in parallel. The magnetic circuit means is associated with the battery strings such that the conductors carrying the electrical current flow through each of the battery strings pass through the magnetic circuit means in directions which cause the electromagnetic fields of at least one predetermined pair of the conductors to oppose each other. In an alternative embodiment, a low voltage converter is associated with each of the battery strings for balancing the electrical current flow through the battery strings.
Developing a process for commercial silica production from Salton Sea brines
Bourcier, W; McCutcheon, M; Leif, R; Bruton, C
2000-09-25T23:59:59.000Z
The goal of this joint LLNL-CalEnergy project is to develop a method for precipitating marketable silica from spent Salton Sea Geothermal Field (SSGF) brines. Many markets for silica exist. We have initially targeted production of silica as a rubber additive. Silica reinforced rubber gives tires less rolling resistance, greater tear strength, and better adhesion to steel belts. Previous silica precipitates produced by CalEnergy from Salton Sea brines were not suitable as rubber additives. They did not to disperse well in the rubber precursors and produced inferior rubber. CalEnergy currently minimizes silica scaling in some of their production facilities by acidifying the brine pH. The rate of silica precipitation slows down as the pH is lowered, so that energy extraction and brine reinfection are possible without unacceptable amounts of scaling even with more than 700 ppm SiO{sub 2} in solution. We are adding a step in which a small amount of base is added to the acidified brine to precipitate silica before reinfection. By carefully controlling the type, rate, and amount of base addition, we can optimize the properties of the precipitate to approach those of an ideal rubber additive.
Casalbuoni, Roberto; Gomis, Joaquim; Longhi, Giorgio [Department of Physics, University of Florence, INFN, Florence (Italy) and Galileo Galilei Institute for Theoretical Physics, Florence (Italy); PH-TH Division, CERN, CH -1211 Geneva 23 (Switzerland) and Departament d'Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Department of Physics, University of Florence and INFN, Florence (Italy)
2007-12-15T23:59:59.000Z
We construct a classical nonrelativistic string model in 3+1 dimensions. The model contains a spurion tensor field that is responsible for the noncommutative structure of the model. Under double-dimensional reduction the model reduces to the exotic nonrelativistic particle in 2+1 dimensions.
Modeling gas and brine migration for assessing compliance of the Waste Isolation Pilot Plant
Vaughn, P. [Applied Physics, Inc., Albuquerque, NM (United States); Butcher, B. [Sandia National Labs., Albuquerque, NM (United States); Helton, J. [Arizona State Univ., Tempe, AZ (United States); Swift, P. [Tech. Reps., Inc., Albuquerque, NM (United States)
1993-10-01T23:59:59.000Z
At the request of the WIPP Project Integration Office (WPIO) of the DOE, the WIPP Performance Assessment (PA) Department of Sandia National Laboratories (SNL) has completed preliminary uncertainty and sensitivity analyses of gas and brine migration away from the undisturbed repository. This paper contains descriptions of the numerical model and simulations, including model geometries and parameter values, and a summary of major conclusions from sensitivity analyses. Because significant transport of contaminants can only occur in a fluid (gas or brine) medium, two-phase flow modeling can provide an estimate of the distance to which contaminants can migrate. Migration of gas or brine beyond the RCRA ``disposal-unit boundary`` or the Standard`s accessible environment constitutes a potential, but not certain, violation and may require additional evaluations of contaminant concentrations.
Rattner, B.A.; Melancon, M.J. [National Biological Survey, Laurel, MD (United States); Capizzi, J.L. [Texas A& M Univ., College Station, TX (United States); King, K.A. [Fish and Wildlife Service, Phoenix, AZ (United States); LeCaptain, L.J. [Fish and Wildlife Service, Spokane, WA (United States)
1995-05-01T23:59:59.000Z
Discharge of oilfield brines into fresh and estuarine waters is a common disposal practice in Texas. Petroleum crude oil (PCO) extraction from underground stores includes the removal of a significant amount of water along with the oil. Several methods may be used to separate the oil and water fractions, including tank batteries, heat separation, and skimming ponds. Disposal of the resultant produced water (oilfield brine) may be accomplished by deep-well injection or discharge to surface waters. In Texas, an estimated 766,000 barrels of oilfield brine were discharged daily into tidal waters in 1979. The maximum concentration for oil and grease in these discharges permitted by the Texas Railroad Commission is 25 ppm. Several studies have shown that oilfield brines are toxic to a wide range of marine life, yet little is known about their effects on birds and mammals. Exposure to petroleum in oilfield wastes could evoke toxicological effects in some waterbird species. Avian responses to PCO exposure are highly variable, including cessation of growth, osmoregulatory impairment, endocrine dysfunction, hemolytic anemia, altered blood chemistry, cytochrome P450 induction, reduced reproductive success, and mortality. Oilfield brine discharges may soon be the largest and most pervasive source of contaminants entering Texas estuaries. Migratory and resident birds feeding in the vicinity of discharge sites may be ingesting food items contaminated with petroleum hydrocarbons, heavy metals and salts in sufficient quantities to evoke toxicity. The present study of wintering western sandpipers (Calidris mauri) that feed and roost near discharge sites sought to examine oilfield brine exposure and effects through quantification of contaminant burdens, morphological characteristics, and cytochrome P450-associated monooxygenase activities. 20 refs., 2 tabs.
Priscu, John C.
Formation and character of an ancient 19-m ice cover and underlying trapped brine in an ``ice bed year-round. New ice-core analysis and tempera- ture data show that beneath 19 m of ice is a water°C. The ice cover thickens at both its base and surface, sealing concentrated brine beneath. The ice
Repassivation of 13% Cr steel dependent on brine pH
Skogsberg, J.W.; Walker, M.L.
2000-02-01T23:59:59.000Z
A joint laboratory project, involving an oil production and oil well service company, investigated repassivation of martensitic 13% Cr steel. The rate at which this alloy is repassivated after losing its protective passive oxide layer to hydrochloric acid (HCI) depended on the pH of the spent acid returns. Test samples of 13% Cr cut from oilfield tubing were subjected to a fluid sequence of (1) initial brine, (2) HCI, (3) spent acid, and (4) final brine. In 9 days, the samples regained their passive oxide layers. When spent acid was taken out of the fluid sequence, the samples regained passive oxide layers in 3 days.
Brine transport studies in the bedded salt of the Waste Isolation Pilot Plant (WIPP)
McTigue, D.F.; Nowak, E.J.
1987-01-01T23:59:59.000Z
Brine flow has been measured to unheated boreholes for periods of a few days and to heated holes for two years in the WIPP facility. It is suggested that Darcy flow may dominate the observed influx of brine. Exact solutions to a linearized model for one-dimensional, radial flow are evaluated for conditions approximating the field experiments. Flow rates of the correct order of magnitude are calculated for permeabilities in the range 10/sup -21/ to 10/sup -20/ m/sup 2/ (1 to 10 nanodarcy) for both the unheated and heated cases. 20 refs., 3 figs., 1 tab.
Munson, D.E.; Jensen, A.L.; Webb, S.W. [Sandia National Labs., Albuquerque, NM (United States); DeVries, K.L. [RE/SPEC, Inc., Rapid City, SD (United States)
1996-02-01T23:59:59.000Z
In a large in situ experimntal circular room, brine inflow was measured over 5 years. After correcting for evaporation losses into mine ventilation air, the measurements gave data for a period of nearly 3 years. Predicted brine accumulation based on a mechanical ``snow plow`` model of the volume swept by creep-induced damage as calculated with the Multimechanism Deformation Coupled Fracture model was found to agree with experiment. Calculation suggests the damage zone at 5 years effectively exends only some 0.7 m into the salt around the room. Also, because the mecahnical model of brine release gives an adequate explanation of the measured data, the hydrological process of brine flow appears to be rapid compared to the mechanical process of brine release.
Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward; /Princeton, Inst. Advanced Study
2006-06-09T23:59:59.000Z
In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.
A. Gorsky; M. Shifman; A. Yung
2006-01-18T23:59:59.000Z
We address two distinct but related issues: (i) the impact of (two-dimensional) axions in a two-dimensional theory known to model confinement, the CP(N-1) model; (ii) bulk axions in four-dimensional Yang-Mills theory supporting non-Abelian strings. In the first case n, \\bar n kinks play the role of "quarks." They are known to be confined. We show that introduction of axions leads to deconfinement (at very large distances). This is akin to the phenomenon of wall liberation in four-dimensional Yang-Mills theory. In the second case we demonstrate that the bulk axion does not liberate confined (anti)monopoles, in contradistinction with the two-dimensional model. A novel physical effect which we observe is the axion radiation caused by monopole-antimonopole pairs attached to the non-Abelian strings.
Coulomb string tension, asymptotic string tension, and the gluon chain
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Greensite, Jeff; Szczepaniak, Adam P.
2015-02-01T23:59:59.000Z
We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.
Classical string in curved backgrounds
Vasilic, Milovan; Vojinovic, Marko [Institute of Physics, P. O. Box 57, 11001 Belgrade (Serbia and Montenegro)
2006-06-15T23:59:59.000Z
The Mathisson-Papapetrou method is originally used for derivation of the particle world line equation from the covariant conservation of its stress-energy tensor. We generalize this method to extended objects, such as a string. Without specifying the type of matter the string is made of, we obtain both the equations of motion and boundary conditions of the string. The world sheet equations turn out to be more general than the familiar minimal surface equations. In particular, they depend on the internal structure of the string. The relevant cases are classified by examining canonical forms of the effective 2-dimensional stress-energy tensor. The case of homogeneously distributed matter with the tension that equals its mass density is shown to define the familiar Nambu-Goto dynamics. The other three cases include physically relevant massive and massless strings, and unphysical tachyonic strings.
Yehoshua, Kolodny
PII S0016-7037(00)00369-0 Ra isotopes and Rn in brines and ground waters of the Jordan-Dead Sea Valley waters being mixtures of fresh water with saline brines. Ra is efficiently extracted from surrounding rocks into the brine end member. 228 Ra/226 Ra ratios are exceptionally low 0.07 to 0.9, mostly
Winckler, Gisela
PII S0016-7037(99)00441-X Sub sea floor boiling of Red Sea Brines: New indication from noble gas in revised form December 8, 1999) Abstract--Hydrothermal brines from the Atlantis II Deep, Red Sea, have been depressions filled by highly saline brines (Hartmann et al., 1998a). The Atlantis II Deep, located
Manning, Craig
Brine-assisted anatexis: Experimental melting in the system haplograniteH2ONaClKCl at deep2O ¼ 0:34 it is 0.55. This "brine trend" is similar to, but more pronounced than, the trend-rich granites. Minimum-melting curves in the presence of brines of constant XH2O have strongly positive d
Physics of String Flux Compactifications
Frederik Denef; Michael R. Douglas; Shamit Kachru
2007-01-06T23:59:59.000Z
We provide a qualitative review of flux compactifications of string theory, focusing on broad physical implications and statistical methods of analysis.
NOBOB-S: Salinity/Brine Exposure as a Biocide for Application to NOBOB Residuals
, eggs and spores of many taxa within the sediments and residual water of their ballast tanks (Niimi a voluntary "best management practices" approach for residual ballast water and sediment for NOBOB vesselsNOBOB-S: Salinity/Brine Exposure as a Biocide for Application to NOBOB Residuals Primary
Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice
Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice M.J. McGuinness \\Lambda , H a programme recently set up to directly measure the thermal conductivity of young sea ice. An array of thermistors frozen into firstyear Antarctic sea ice provides temperature against depth data, which is fitted
Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production Radomir Schmidt,, Prapakorn Tantoyotai, Sirine C. Fakra, Matthew A, Saskatchewan S7N 5E2, Canada United States Department of Agriculture, Agricultural Research Service, SJVASC
Analysis of hydrocarbon removal methods for the management of oilfield brines and produced waters
Furrow, Brendan Eugene
2005-11-01T23:59:59.000Z
and globally, the petroleum industries challenge has been to develop a high-tech and cost effective method to purify the large volumes of oilfield brines and produced water. Currently, most of the produced water requires several pre- and post- treatment methods...
Sulfate Removal from Reject Brined in Inland Desalination with Zero Liquid Discharge
Almasri, Dema A
2013-07-03T23:59:59.000Z
Sulfate is one of the most problematic ions present in reject brine in desalination systems due to its high potential of scale formation and membrane fouling; making it an obstacle in the application of zero liquid discharge. The ultra-high lime...
Salt Brine Blending to Optimize Deicing and Anti-icing Performance and Cost
Minnesota, University of
Salt Brine Blending to Optimize Deicing and Anti-icing Performance and Cost Effectiveness Stephen J in Method? #12;Deicing and Anti-icing Treatments ·Sodium Chloride (NaCl) ·Cargill, NA Salt ·Magnesium Chloride (MgCl2) w/additives ·Envirotech Serv., Scotwood Ind., NA Salt ·Calcium Chloride (CaCl2) ·Tiger
RHIC | String Theory Predicts an Experimental Result
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
that originally appeared in the online publication symmetry breaking. A first: String theory predicts an experimental result One of the biggest criticisms of string theory is that...
Castaneda, Jaime N.; Cote, Raymond O.; Torczynski, John Robert; O'Hern, Timothy John
2004-05-01T23:59:59.000Z
An experimental program was conducted to study a proposed approach for oil reintroduction in the Strategic Petroleum Reserve (SPR). The goal was to assess whether useful oil is rendered unusable through formation of a stable oil-brine emulsion during reintroduction of degassed oil into the brine layer in storage caverns. An earlier report (O'Hern et al., 2003) documented the first stage of the program, in which simulant liquids were used to characterize the buoyant plume that is produced when a jet of crude oil is injected downward into brine. This report documents the final two test series. In the first, the plume hydrodynamics experiments were completed using SPR oil, brine, and sludge. In the second, oil reinjection into brine was run for approximately 6 hours, and sampling of oil, sludge, and brine was performed over the next 3 months so that the long-term effects of oil-sludge mixing could be assessed. For both series, the experiment consisted of a large transparent vessel that is a scale model of the proposed oil-injection process at the SPR. For the plume hydrodynamics experiments, an oil layer was floated on top of a brine layer in the first test series and on top of a sludge layer residing above the brine in the second test series. The oil was injected downward through a tube into the brine at a prescribed depth below the oil-brine or sludge-brine interface. Flow rates were determined by scaling to match the ratio of buoyancy to momentum between the experiment and the SPR. Initially, the momentum of the flow produces a downward jet of oil below the tube end. Subsequently, the oil breaks up into droplets due to shear forces, buoyancy dominates the flow, and a plume of oil droplets rises to the interface. The interface was deflected upward by the impinging oil-brine plume. Videos of this flow were recorded for scaled flow rates that bracket the equivalent pumping rates in an SPR cavern during injection of degassed oil. Image-processing analyses were performed to quantify the penetration depth and width of the oil jet. The measured penetration depths were shallow, as predicted by penetration-depth models, in agreement with the assumption that the flow is buoyancy-dominated, rather than momentum-dominated. The turbulent penetration depth model overpredicted the measured values. Both the oil-brine and oil-sludge-brine systems produced plumes with hydrodynamic characteristics similar to the simulant liquids previously examined, except that the penetration depth was 5-10% longer for the crude oil. An unexpected observation was that centimeter-size oil 'bubbles' (thin oil shells completely filled with brine) were produced in large quantities during oil injection. The mixing experiments also used layers of oil, sludge, and brine from the SPR. Oil was injected at a scaled flow rate corresponding to the nominal SPR oil injection rates. Injection was performed for about 6 hours and was stopped when it was evident that brine was being ingested by the oil withdrawal pump. Sampling probes located throughout the oil, sludge, and brine layers were used to withdraw samples before, during, and after the run. The data show that strong mixing caused the water content in the oil layer to increase sharply during oil injection but that the water content in the oil dropped back to less than 0.5% within 16 hours after injection was terminated. On the other hand, the sediment content in the oil indicated that the sludge and oil appeared to be well mixed. The sediment settled slowly but the oil had not returned to the baseline, as-received, sediment values after approximately 2200 hours (3 months). Ash content analysis indicated that the sediment measured during oil analysis was primarily organic.
Twist Field as Three String Interaction Vertex in Light Cone String Field Theory
Isao Kishimoto; Sanefumi Moriyama; Shunsuke Teraguchi
2007-03-22T23:59:59.000Z
It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.
David J. Gross; Washington Taylor
2001-06-04T23:59:59.000Z
We describe projection operators in the matter sector of Witten's cubic string field theory using modes on the right and left halves of the string. These projection operators represent a step towards an analytic solution of the equations of motion of the full string field theory, and can be used to construct Dp-brane solutions of the string field theory when the BRST operator Q is taken to be pure ghost, as suggested in the recent conjecture by Rastelli, Sen and Zwiebach. We show that a family of solutions related to the sliver state are rank one projection operators on the appropriate space of half-string functionals, and we construct higher rank projection operators corresponding to configurations of multiple D-branes.
David J. Gross; Washington Taylor
2001-06-27T23:59:59.000Z
We describe the ghost sector of cubic string field theory in terms of degrees of freedom on the two halves of a split string. In particular, we represent a class of pure ghost BRST operators as operators on the space of half-string functionals. These BRST operators were postulated by Rastelli, Sen, and Zwiebach to give a description of cubic string field theory in the closed string vacuum arising from condensation of a D25-brane in the original tachyonic theory. We find a class of solutions for the ghost equations of motion using the pure ghost BRST operators. We find a vanishing action for these solutions, and discuss possible interpretations of this result. The form of the solutions we find in the pure ghost theory suggests an analogous class of solutions in the original theory on the D25-brane with BRST operator Q_B coupling the matter and ghost sectors.
Summing Planar Bosonic Open Strings
Bardakci, Korkut
2006-02-16T23:59:59.000Z
In earlier work, planar graphs of massless {phi}{sup 3} theory were summed with the help of the light cone world sheet picture and the mean field approximation. In the present article, the same methods are applied to the problem of summing planar bosonic open strings. They find that in the ground state of the system, string boundaries form a condensate on the world sheet, and a new string emerges from this summation. Its slope is always greater than the initial slope, and it remains non-zero even when the initial slope is set equal to zero. If they assume the initial string tends to a field a theory in the zero slope limit, this result provides evidence for string formation in field theory.
Strings, higher curvature corrections, and black holes
Thomas Mohaupt
2005-12-05T23:59:59.000Z
We review old and recent results on subleading contributions to black hole entropy in string theory.
String bit models for superstring
Bergman, O.; Thorn, C.B.
1995-12-31T23:59:59.000Z
The authors extend the model of string as a polymer of string bits to the case of superstring. They mainly concentrate on type II-B superstring, with some discussion of the obstacles presented by not II-B superstring, together with possible strategies for surmounting them. As with previous work on bosonic string work within the light-cone gauge. The bit model possesses a good deal less symmetry than the continuous string theory. For one thing, the bit model is formulated as a Galilei invariant theory in (D {minus} 2) + 1 dimensional space-time. This means that Poincare invariance is reduced to the Galilei subgroup in D {minus} 2 space dimensions. Naturally the supersymmetry present in the bit model is likewise dramatically reduced. Continuous string can arise in the bit models with the formation of infinitely long polymers of string bits. Under the right circumstances (at the critical dimension) these polymers can behave as string moving in D dimensional space-time enjoying the full N = 2 Poincare supersymmetric dynamics of type II-B superstring.
Radio bursts from superconducting strings
Yi-Fu Cai; Eray Sabancilar; Tanmay Vachaspati
2012-01-30T23:59:59.000Z
We show that radio bursts from cusps on superconducting strings are linearly polarized, thus, providing a signature that can be used to distinguish them from astrophysical sources. We write the event rate of string-generated radio transients in terms of observational variables, namely, the event duration and flux. Assuming a canonical set of observational parameters, we find that the burst event rate can be quite reasonable, e.g., order ten a year for Grand Unified strings with 100 TeV currents, and a lack of observed radio bursts can potentially place strong constraints on particle physics models.
Radio Broadcasts from Superconducting Strings
Yi-Fu Cai; Eray Sabancilar; Daniele A. Steer; Tanmay Vachaspati
2012-05-14T23:59:59.000Z
Superconducting cosmic strings can give transient electromagnetic signatures that we argue are most evident at radio frequencies. We investigate the three different kinds of radio bursts from cusps, kinks, and kink-kink collisions on superconducting strings. We find that the event rate is dominated by kink bursts in a range of parameters that are of observational interest, and can be quite high (several a day at 1 Jy flux) for a canonical set of parameters. In the absence of events, the search for radio transients can place stringent constraints on superconducting cosmic strings.
Geometry, topology, and string theory
Varadarajan, Uday
2003-07-10T23:59:59.000Z
A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.
C. S. Lam
1994-06-24T23:59:59.000Z
A low energy string theory should reduce to an ordinary quantum field theory, but in reality the structures of the two are so different as to make the equivalence obscure. The string formalism is more symmetrical between the spacetime and the internal degrees of freedom, thus resulting in considerable simplification in practical calculations and novel insights in theoretical understandings. We review here how tree or multiloop field-theoretical diagrams can be organized in a string-like manner to take advantage of this computational and conceptual simplicity.
M-strings, Elliptic Genera and N=4 String Amplitudes
Stefan Hohenegger; Amer Iqbal
2014-03-11T23:59:59.000Z
We study mass-deformed N=2 gauge theories from various points of view. Their partition functions can be computed via three dual approaches: firstly, (p,q)-brane webs in type II string theory using Nekrasov's instanton calculus, secondly, the (refined) topological string using the topological vertex formalism and thirdly, M theory via the elliptic genus of certain M-strings configurations. We argue for a large class of theories that these approaches yield the same gauge theory partition function which we study in detail. To make their modular properties more tangible, we consider a fourth approach by connecting the partition function to the equivariant elliptic genus of R^4 through a (singular) theta-transform. This form appears naturally as a specific class of one-loop scattering amplitudes in type II string theory on T^2, which we calculate explicitly.
Stein, C.L.; Krumhansl, J.L.
1986-03-01T23:59:59.000Z
We present here analyses of macro- and microscopic (intracrystalline) brines observed within the WIPP facility and in the surrounding halite, with interpretations regarding the origin and history of these fluids and their potential effect(s) on long-term waste storage. During excavation, several large fluid inclusions were recovered from an area of highly recrystallized halite in a thick salt bed at the repository horizon (2150 ft below ground level). In addition, 52 samples of brine ''weeps'' were collected from walls of recently excavated drifts at the same stratigraphic horizon from which the fluid inclusion samples are assumed to have been taken. Analyses of these fluids show that they differ substantially in composition from the inclusion fluids and cannot be explained by mixing of the fluid inclusion populations. Finally, holes in the facility floor that filled with brine were sampled but with no stratographic control; therefore it is not possible to interpret the compositions of these brines with any accuracy, except insofar as they resemble the weep compositions but with greater variation in both K/Mg and Na/Cl ratios. However, the Ca and SO/sub 4/ values for the floor holes are relatively close to the gypsum saturation curve, suggesting that brines filling floor holes have been modified by the presence of gypsum or anhydrite, possibly even originating in one or more of the laterally continuous anhydrite units referred to in the WIPP literature as marker beds. In conclusion, the wide compositional variety of fluids found in the WIPP workings suggest that (1) an interconnected hydrologic system which could effectively transport radonuclides away from the repository does not exist; (2) brine migration studies and experiments must consider the mobility of intergranular fluids as well as those in inclusions; and (3) near- and far-field radionuclide migration testing programs need to consider a wide range of brine compositions rather than a few reference brines.
West Hackberry Brine Disposal Project pre-discharge characterization. Final report
DeRouen, L.R.; Hann, R.W.; Casserly, D.M.; Giammona, C. (eds.) [eds.
1982-01-01T23:59:59.000Z
The physical, chemical and biological attributes are described for: (1) a coastal marine environment centered about a Department of Energy Strategic Petroleum Reserve (SPR) brine disposal site 11.4 km off the southwest coast of Louisiana; and (2) the lower Calcasieu and Sabine estuarine systems that provide leach waters for the SPR project. A three month sampling effort, February through April 1981, and previous investigations from the study area are integrated to establish baseline information for evaluation of impacts from brine disposal in the nearshore marine waters and from freshwater withdrawal from the coastal marsh of the Chenier Plain. January data are included for some tasks that sampled while testing and mobilizing their instruments prior to the February field effort. The study addresses the areas of physical oceanography, estuarine hydrology and hydrography, water and sediment quality, benthos, nekton, phytoplankton, zooplankton, and data management.
Goddard, William
2012-11-30T23:59:59.000Z
To further our understanding and develop the method for measuring the DICs under geological sequestration conditions, we studied the infrared spectra of DICs under high pressure and temperature conditions. First principles simulations of DICs in brine conditions were performed using a highly optimized ReaxFF-DIC forcefield. The thermodynamics stability of each species were determined using the 2PT method, and shown to be consistent with the Reax simulations. More importantly, we have presented the IR spectra of DIC in real brine conditions as a function of temperature and pressure. At near earth conditions, we find a breaking of the O-C-O bending modes into asymmetric and symmetric modes, separated by 100cm{sup -1} at 400K and 5 GPa. These results can now be used to calibrate FTIR laser measurements.
Aromatic hydrocarbons associated with brines from geopressured wells. Annual report, fiscal 1985
Keeley, D.F.; Meriwether, J.R.
1985-01-01T23:59:59.000Z
Samples of cryocondensates - materials condensed at - 78.5/sup 0/C were taken on a regular basis from the gas stream for the USDOE geopressured wells. Most of the data has been taken from the Gladys McCall well as it has flowed on a regular and almost continous basis. The cryocondensates, not the ''condensate'' from gas wells, are almost exclusively aromatic hydrocarbons, primarily benzene, toluene, ethylbenzene, and the xylenes, but contain over 95 compounds, characterized using gas chromatographic-mass spectroscopy. The solubility in water and brine of benezene, toluene, ethylbenzene and o-xylene, some of the components of the cryocondensate, as well as distribution coefficients between water or brine and a standard oil have been measured. 25 refs.
Biochemical solubilization of toxic salts from residual geothermal brines and waste waters
Premuzic, Eugene T. (East Moriches, NY); Lin, Mow S. (Rocky Point, NY)
1994-11-22T23:59:59.000Z
A method of solubilizing metal salts such as metal sulfides in a geothermal sludge using mutant Thiobacilli selected for their ability to metabolize metal salts at high temperature is disclosed, The method includes the introduction of mutated Thiobacillus ferrooxidans and Thiobacillus thiooxidans to a geothermal sludge or brine. The microorganisms catalyze the solubilization of metal salts, For instance, in the case of metal sulfides, the microorganisms catalyze the solubilization to form soluble metal sulfates.
Biochemical solubilization of toxic salts from residual geothermal brines and waste waters
Premuzic, E.T.; Lin, M.S.
1994-11-22T23:59:59.000Z
A method of solubilizing metal salts such as metal sulfides in a geothermal sludge using mutant Thiobacilli selected for their ability to metabolize metal salts at high temperature is disclosed. The method includes the introduction of mutated Thiobacillus ferrooxidans and Thiobacillus thiooxidans to a geothermal sludge or brine. The microorganisms catalyze the solubilization of metal salts. For instance, in the case of metal sulfides, the microorganisms catalyze the solubilization to form soluble metal sulfates. 54 figs.
Sulfate Removal from Reject Brined in Inland Desalination with Zero Liquid Discharge
Almasri, Dema A
2013-07-03T23:59:59.000Z
SULFATE REMOVAL FROM REJECT BRINED IN INLAND DESALINATION WITH ZERO LIQUID DISCHARGE A Thesis by DEMA ALMASRI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... and help. I am thankful for my colleagues for their inspiration and assistance throughout the years in Texas A&M at Qatar. I am also grateful to my exceptional friends that were always there during my ups and downs. I am thankful for my irreplaceable...
Andrea Ferrantelli; Paul Melóis; Miska Räikkönen; Martti Viljanen
2013-05-03T23:59:59.000Z
This work is the first in a series of articles addressing the energy optimization in ice hockey halls. Here we adopt an analytical method, called functional optimization, to find which design and operating conditions maximize the Coefficient Of Performance of the entire cooling system (brine pumps and cooling tower), which we call ${\\rm COP}_{sys}$. This is addressed as a function of several variables, like electric consumption and brine physical properties. By maximizing such function, the best configuration and brine choices for the system can thus be determined accurately and rigorously. We investigate the importance of pipe diameter, depth and brine type (ethylene glycol and ammonia) for average-sized ice rinks. An optimal brine density is found, and we compute the weight of the electric consumption of the brine pumps on ${\\rm COP}_{sys}$. Our formulas are validated with heat flow measurement data obtained at an ice hockey hall in Finland. They are also confronted with technical and cost-related constraints, and implemented by simulations with the program COMSOL Multiphysics. The multivariable approach here discussed is general, and can be applied to the rigorous preliminary study of diverse situations in building physics and in many other areas of interest.
Tolerance to cadmium and cadmium-binding ligands in Great Salt Lake brine shrimp (Artemia salina)
Jayasekara, S.; Drown, D.B.; Sharma, R.P.
1986-02-01T23:59:59.000Z
Information on the accumulation of cadmium in cytosolic proteins of Great Lake brine shrimp (Artemia salina) was obtained from animals collected directly from the lake and also from animal hatched and maintained in three sublethal concentrations of cadmium (0.5, 2.0, 5.0 ppm) in saltwater aquaria. Brine shrimp growth under these conditions was monitored by measuring body lengths during a 7-day exposure period. Heat-stable, cadmium-binding ligands were isolated and identified by Sephadex G-75 chromatography and atomic absorption spectrophotometry. Cadmium was found to be equally distributed between high and low molecular weight proteins in animals collected from the lake and the 0.5 ppm cadmium group. There was also a slight growth stimulation noted in the 0.5-pm group. Higher cadmium incorporation was noted in low molecular weight fractions with increasing cadmium concentration in the exposure media. Low molecular weight fractions were also found to have high uv absorption characteristics at 250 nm and low absorption at 280 nm. Molecular weight of the cadmium-binding ligands was found to be 11,000 as estimated by the gel filtration method. De novo synthesis of this protein was increased as a function of cadmium concentration in the media. However, slow accumulation of cadmium in other protein fractions was also noticed in higher cadmium exposure groups, suggesting the existence of possible tolerance mechanisms in brine shrimp exposed to suspected acute cadmium concentrations.
Utilizing rare earth elements as tracers in high TDS reservoir brines in CCS applications
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
McLing, Travis; Smith, William; Smith, Robert
2014-01-01T23:59:59.000Z
In this paper we report the result of research associated with the testing of a procedures necessary for utilizing natural occurring trace elements, specifically the Rare Earth Elements (REE) as geochemical tracers in Carbon Capture and Storage (CCS) applications. Trace elements, particularly REE may be well suited to serve as in situ tracers for monitoring geochemical conditions and the migration of CO?-charged waters within CCS storage systems. We have been conducting studies to determine the efficacy of using REE as a tracer and characterization tool in the laboratory, at a CCS analogue site in Soda Springs, Idaho, and at amore »proposed CCS reservoir at the Rock Springs Uplift, Wyoming. Results from field and laboratory studies have been encouraging and show that REE may be an effective tracer in CCS systems and overlying aquifers. In recent years, a series of studies using REE as a natural groundwater tracer have been conducted successfully at various locations around the globe. Additionally, REE and other trace elements have been successfully used as in situ tracers to describe the evolution of deep sedimentary Basins. Our goal has been to establish naturally occurring REE as a useful monitoring measuring and verification (MMV) tool in CCS research because formation brine chemistry will be particularly sensitive to changes in local equilibrium caused by the addition of large volumes of CO?. Because brine within CCS target formations will have been in chemical equilibrium with the host rocks for millions of years, the addition of large volumes of CO? will cause reactions in the formation that will drive changes to the brine chemistry due to the pH change caused by the formation of carbonic acid. This CO? driven change in formation fluid chemistry will have a major impact on water rock reaction equilibrium in the formation, which will impart a change in the REE fingerprint of the brine that can measured and be used to monitor in situ reservoir conditions. Our research has shown that the REE signature imparted to the formation fluid by the introduction of CO? to the formation, can be measured and tracked as part of an MMV program. Additionally, this REE fingerprint may serve as an ideal tracer for fluid migration, both within the CCS target formation, and should formation fluids migrate into overlying aquifers. However application of REE and other trace elements to CCS system is complicated by the high salt content of the brines contained within the target formations. In the United States by regulation, in order for a geologic reservoir to be considered suitable for carbon storage, it must contain formation brine with total dissolved solids (TDS) > 10,000 ppm, and in most cases formation brines have TDS well in excess of that threshold. The high salinity of these brines creates analytical problems for elemental analysis, including element interference with trace metals in Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) (i.e. element mass overlap due to oxide or plasma phenomenon). Additionally, instruments like the ICP-MS that are sensitive enough to measure trace elements down to the parts per trillion level are quickly oversaturated when water TDS exceeds much more than 1,000 ppm. Normally this problem is dealt with through dilution of the sample, bringing the water chemistry into the instruments working range. However, dilution is not an option when analyzing these formation brines for trace metals, because trace elements, specifically the REE, which occur in aqueous solutions at the parts per trillion levels. Any dilution of the sample would make REE detection impossible. Therefore, the ability to use trace metals as in situ natural tracers in high TDS brines environments requires the development of methods for pre-concentrating trace elements, while reducing the salinity and associated elemental interference such that the brines can be routinely analyzed by standard ICP-MS methods. As part of the Big Sky Carbon Sequestration Project the INL-CAES has developed a rapid, easy to use proces
Burnett, David
2012-12-31T23:59:59.000Z
The goal of the A&M DOE NETL Project No. DE-FE0000847 was to develop a mobile, multifunctional water treatment capability designed specifically for “pre-treatment” of field waste brine. The project consisted of constructing s mobile “field laboratory” incorporating new technology for treating high salinity produced water and using the lab to conduct a side-by-side comparison between this new technology and that already existing in field operations. A series of four field trials were performed utilizing the mobile unit to demonstrate the effectiveness of different technology suitable for use with high salinity flow back brines and produced water. The design of the mobile unit was based on previous and current work at the Texas A&M Separation Sciences Pilot Plant. The several treatment techniques which have been found to be successful in both pilot plant and field tests had been tested to incorporate into a single multifunctional process train. Eight different components were evaluated during the trials, two types of oil and grease removal, one BTEX removal step, three micro-filters, and two different nanofilters. The performance of each technique was measured by its separation efficiency, power consumption, and ability to withstand fouling. The field trials were a success. Four different field brines were evaluated in the first trial in New York. Over 16,000 gallons of brine were processed. Using a power cost of $.10 per kWh, media pretreatment power use averaged $0.004 per barrel, solids removal $.04 per barrel and brine “softening” $.84 per barrel. Total power cost was approximately $1.00 per barrel of fluid treated. In Pennsylvania, brines collected from frac ponds were tested in two additional trials. Each of the brines was converted to an oil-free, solids-free brine with no biological activity. Brines were stable over time and would be good candidates for use as a make-up fluid in a subsequent fracturing fluid design. Reports on all of the field trials and subcontractor research have been summarized in this Final Report. Individual field trial reports and research reports are contained in the companion volume titled “Appendices”
Acoustic data transmission through a drill string
Drumheller, D.S.
1988-04-21T23:59:59.000Z
Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. 5 figs.
Finite Temperature Gases of Fermionic Strings
Shyamoli Chaudhuri
2005-09-12T23:59:59.000Z
We show that in the absence of a Ramond-Ramond sector both the type IIA and type IIB free string gases have a thermal instability due to low temperature tachyon modes. The gas of free IIA strings undergoes a thermal duality transition into a gas of free IIB strings at the self-dual temperature. The free heterotic string gas is a tachyon-free ensemble with gauge symmetry SO(16)$\\times$SO(16) in the presence of a timelike Wilson line background. It exhibits a holographic duality relation undergoing a self-dual phase transition with positive free energy and positive specific heat. The type IB open and closed string ensemble is related by thermal duality to the type I' string ensemble. We identify the order parameter for the Kosterlitz-Thouless phase transition from a low temperature gas of short open strings to a high temperature long string phase at or below T_C. Note Added (Sep 2005).
Quadratic superconducting cosmic strings revisited
Mustapha Azreg-Aïnou
2008-02-22T23:59:59.000Z
It has been shown that 5-dimensional general relativity action extended by appropriate quadratic terms admits a singular superconducting cosmic string solution. We search for cosmic strings endowed with similar and extended physical properties by directly integrating the non-linear matrix field equations thus avoiding the perturbative approach by which we constructed the above-mentioned \\textsl{exact} solution. The most general superconducting cosmic string, subject to some constraints, will be derived and shown to be mathematically \\textsl{unique} up to linear coordinate transformations mixing its Killing vectors. The most general solution, however, is not globally equivalent to the old one due to the existence of Killing vectors with closed orbits.
Advanced biochemical processes for geothermal brines FY 1998 annual operating plan
NONE
1997-10-01T23:59:59.000Z
As part of the overall Geothermal Energy Research which is aimed at the development of economical geothermal resources production systems, the aim of the Advanced Biochemical Processes for Geothermal Brines (ABPGB) effort is the development of economic and environmentally acceptable methods for disposal of geothermal wastes and conversion of by-products to useful forms. Methods are being developed for dissolution, separation and immobilization of geothermal wastes suitable for disposal, usable in inert construction materials, suitable for reinjection into the reservoir formation, or used for recovery of valuable metals.
Introduction to the theory of strings
Peskin, M.E.
1985-10-01T23:59:59.000Z
These lectures present, from an introductory perspective, some basic aspects of the quantum theory of strings. They treat (1) the kinematics, spectrum, and scattering amplitude of the bosonic string, (2) the spectrum and supersymmetry of Green-Schwarz superstring, and (3) the identification of the underlying gauge invariances of the string theory. 43 refs.
p-Adic Strings and Their Applications
Freund, Peter G. O. [Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States); Department of Physics, University of Chicago, Chicago, IL 60637 (United States)
2006-03-29T23:59:59.000Z
The theory of p-adic strings is reviewed along with some of their applications, foremost among them to the tachyon condensation problem in string theory. Some open problems are discussed, in particular that of the superstring in 10 dimensions as the end-stage of the 26-dimensional closed bosonic string's tachyon condensation.
Non-Abelian Strings and Axions
Shifman, M. [William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN 55455 (United States)
2010-08-30T23:59:59.000Z
Axion-like fields can have a strong impact on non-Abelian strings. I discuss axion connection to such strings and its implications in two cases: (i) axion localized on the strings, and (ii) axions propagating in the four-dimensional bulk.
String Theory at Snowmass Michael Dine
California at Santa Cruz, University of
String Theory at Snowmass Michael Dine Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (Dated: September 23, 2002) This is the summary talk for the String Theory interested in string theory, quantum gravity, and related issues met to discuss the questions: which future
Ultraviolet Limit of Open String Theory
Shyamoli Chaudhuri
2005-01-21T23:59:59.000Z
We confirm the intuition that a string theory which is perturbatively infrared finite is automatically perturbatively ultraviolet finite. Our derivation based on the asymptotics of the Selberg trace formula for the Greens function on a Riemann surface holds for both open and closed string amplitudes and is independent of modular invariance and supersymmetry. The mass scale for the open strings stretched between Dbranes suggests a natural world-sheet ultraviolet regulator in the string path integral, preserving both T-duality and open-closed string world-sheet duality. Note added (Jan 2005): Comments and related references added.
Superconducting Hair on Charged Black String Background
Lukasz Nakonieczny; Marek Rogatko
2012-01-25T23:59:59.000Z
Behaviour of Dirac fermions in the background of a charged black string penetrated by an Abelian Higgs vortex is elaborated. One finds the evidence that the system under consideration can support fermion fields acting like a superconducting cosmic string in the sence that a nontrivial Dirac fermion field can be carried by the system in question. The case of nonextremal and extremal black string vortex systems were considered. The influence of electric and Higgs charge, the winding number and the fermion mass on the fermion localization near the black string event horizon was studied. It turned out that the extreme charged black string expelled fermion fields more violently comparing to the nonextremal one.
Taylor, K.C.; Burke, R.A.; Schramm, L.L. [Petroleum Recovery Inst., Calgary, Alberta (Canada); Nasr-El-Din, H.A. [Saudi Aramco, Dhahran (Saudi Arabia)
1995-11-01T23:59:59.000Z
An automated method for the determination of acrylamide polymers by flow injection analysis (FIA) has been developed and optimized for routine use. The method has been extensively tested for interferences common in oilfield brines. Potential interferences were examined from Na{sup +}, Ca{sup 2+}, Cr{sup 3+}, Al{sup 3+}, Zr{sup 3+}, NH{sub 4}{sup +}, Cl{sup {minus}}, OH{sup {minus}}, CO{sub 3}{sup 2{minus}}, sample coloration, and commonly used surfactants. The analysis is specific for amides, and the sensitivity to concentration of amide groups in the polymer was shown to be constant as the degree of polymer hydrolysis was varied. The range of the method is 0.1 to 100 mg/L. Sample throughput is 30 samples/h with triplicate analysis. Relative standard deviations of 0.2% are readily obtained from standard solutions and 0.5% from complex samples (at 50 mg/L). The method is applicable to the determination of aqueous, acrylamide-based polymers in process streams, surface waters and oilfield brines.
David B. Burnett
2004-09-29T23:59:59.000Z
Produced water is a major waste generated at the oil and natural gas wells in the state of Texas. This water could be a possible source of new fresh water to meet the growing demands of the state after treatment and purification. Treatment of brine generated in oil fields or produced water with an ultrafiltration membranes were the subject of this thesis. The characterization of ultrafiltration membranes for oil and suspended solids removal of produced water, coupled with the reverse osmosis (RO) desalination of brine were studied on lab size membrane testing equipment and a field size testing unit to test whether a viable membrane system could be used to treat produced water. Oil and suspended solids were evaluated using turbidity and oil in water measurements taken periodically. The research considered the effect of pressure and flow rate on membrane performance of produced water treatment of three commercially available membranes for oily water. The study also analyzed the flux through the membrane and any effect it had on membrane performance. The research showed that an ultrafiltration membrane provided turbidity removal of over 99% and oil removal of 78% for the produced water samples. The results indicated that the ultrafiltration membranes would be asset as one of the first steps in purifying the water. Further results on selected RO membranes showed that salt rejection of greater than 97% could be achieved with satisfactory flux and at reasonable operating cost.
Dudak, B.; Galbraith, R.; Hansen, L.; Sverjensky, D.; Weres, O.
1982-07-01T23:59:59.000Z
The development of a flowthrough sampler capable of obtaining fluid samples from geopressured wells at temperatures up to 400/sup 0/F and pressures up to 20,000 psi is described. The sampler has been designed, fabricated from MP35N alloy, laboratory tested, and used to obtain fluid samples from a geothermal well at The Geysers, California. However, it has not yet been used in a geopressured well. The design features, test results, and operation of this device are described. Alternative sampler designs are also discussed. Another activity was to review the chemistry and geochemistry of geopressured brines and reservoirs, and to evaluate the utility of available computer codes for modeling the chemistry of geopressured brines. The thermodynamic data bases for such codes are usually the limiting factor in their application to geopressured systems, but it was concluded that existing codes can be updated with reasonable effort and can usefully explain and predict the chemical characteristics of geopressured systems, given suitable input data.
Modeling Coupled THMC Processes and Brine Migration in Salt at High Temperatures
Rutqvist, Jonny; Blanco Martin, Laura; Mukhopadhyay, Sumit; Houseworth, Jim; Birkholzer, Jens
2014-08-14T23:59:59.000Z
In this report, we present FY2014 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. LBNL’s work on the modeling of coupled THMC processes in salt was initiated in FY2012, focusing on exploring and demonstrating the capabilities of an existing LBNL modeling tool (TOUGH-FLAC) for simulating temperature-driven coupled flow and geomechanical processes in salt. This work includes development related to, and implementation of, essential capabilities, as well as testing the model against relevant information and published experimental data related to the fate and transport of water. we provide more details on the FY2014 work, first presenting updated tools and improvements made to the TOUGH-FLAC simulator, and the use of this updated tool in a new model simulation of long-term THM behavior within a generic repository in a salt formation. This is followed by the description of current benchmarking and validations efforts, including the TSDE experiment. We then present the current status in the development of constitutive relationships and the dual-continuum model for brine migration. We conclude with an outlook for FY2015, which will be much focused on model validation against field experiments and on the use of the model for the design studies related to a proposed heater experiment.
Summary Results for Brine Migration Modeling Performed by LANL LBNL and SNL for the UFD Program
Kuhlman, Kristopher L
2014-09-01T23:59:59.000Z
This report summarizes laboratory and field observations and numerical modeling related to coupled processes involving brine and vapor migration in geologic salt, focusing on recent developments and studies conducted at Sandia, Los Alamos, and Berkeley National Laboratories. Interest into the disposal of heat-generating waste in salt has led to interest into water distribution and migration in both run-of-mine crushed and intact geologic salt. Ideally a fully coupled thermal-hydraulic-mechanical-chemical simulation is performed using numerical models with validated constitutive models and parameters. When mechanical coupling is not available, mechanical effects are prescribed in hydraulic models as source, boundary, or initial conditions. This report presents material associated with developing appropriate initial conditions for a non-mechanical hydrologic simulation of brine migration in salt. Due to the strong coupling between the mechanical and hydrologic problems, the initial saturation will be low for the excavation disturbed zone surrounding the excavation. Although most of the material in this report is not new, the author hopes it is presented in a format making it useful to other salt researchers.
String Universality in Six Dimensions
Vijay Kumar; Washington Taylor
2009-10-10T23:59:59.000Z
In six dimensions, cancellation of gauge, gravitational, and mixed anomalies strongly constrains the set of quantum field theories which can be coupled consistently to gravity. We show that for some classes of six-dimensional supersymmetric gauge theories coupled to gravity, the anomaly cancellation conditions are equivalent to tadpole cancellation and other constraints on the matter content of heterotic/type I compactifications on K3. In these cases, all consistent 6D supergravity theories have a realization in string theory. We find one example which may arise from a novel string compactification, and we identify a new infinite family of models satisfying anomaly factorization. We find, however, that this infinite family of models, as well as other infinite families of models previously identified by Schwarz are pathological. We suggest that it may be feasible to demonstrate that there is a string theoretic realization of all consistent six-dimensional supergravity theories which have Lagrangian descriptions with arbitrary gauge and matter content. We attempt to frame this hypothesis of string universality as a concrete conjecture.
Gordon Chalmers; Olaf Lechtenfeld; Bernd Niemeyer
2000-09-08T23:59:59.000Z
We calculate the genus-one three- and four-point amplitudes in the 2+2 dimensional closed N=(2,2) worldsheet supersymmetric string within the RNS formulation. Vertex operators are redefined with the incorporation of spinor helicity techniques, and the quantum scattering is shown to be manifestly gauge and Lorentz invariant after normalizing the string states. The continuous spin structure summation over the monodromies of the worldsheet fermions is carried out explicitly, and the field-theory limit is extracted. The amplitude in this limit is shown to be the maximally helicity violating amplitude in pure gravity evaluated in a two-dimensional setting, which vanishes, unlike the four-dimensional result. The vanishing of the genus-one N=2 closed string amplitude is related to the absence of one-loop divergences in dimensionally regulated IIB supergravity. Comparisons and contrasts between self-dual field theory and the N=2 string theory are made at the quantum level; they have different S-matrices. Finally, we point to further relations with self-dual field theory and two-dimensional models.
String universality in ten dimensions
Allan Adams; Oliver DeWolfe; Washington Taylor
2014-10-29T23:59:59.000Z
We show that the ${\\cal N}=1$ supergravity theories in ten dimensions with gauge groups $U(1)^{496}$ and $E_8 \\times U(1)^{248}$ are not consistent quantum theories. Cancellation of anomalies cannot be made compatible with supersymmetry and abelian gauge invariance. Thus, in ten dimensions all supersymmetric theories of gravity without known inconsistencies are realized in string theory.
Barton, Mark D.
Barton, M.D.and Johnson, D.A., 2000 -Alternative Brine Sources for Fe-Oxide (-Cu-Au) Systems-Gold &Related Deposits: AGlobal Perspective, Australian Mineral Foundation, Adelaide, pp 43-60 ALTERNATIVE BRINE, and the broader geologic setting(s). Geologic and geochemical evidence show that the ore-forming fluids are brines
Ferrantelli, Andrea; Räikkönen, Miska; Viljanen, Martti
2012-01-01T23:59:59.000Z
This work is the first of a series of articles addressing the energy optimization in ice hockey halls. Here we outline an analytic method to predict in which design and operating conditions the COP of the entire cooling system (refrigerator and cooling tower) ${\\rm COP}_{sys}$ is maximum. ${\\rm COP}_{sys}$ is investigated as a function of several variables, like electric consumption and brine physical properties. With this method, the best configuration and brine choices for the system can therefore be determined in advance. We estimate the optimal design of an average-sized ice rink, including pipe diameter, depth and brine type (ethylene glycol and ammonia). We also single out an optimal brine density and show the impact of the electric consumption of the pump on ${\\rm COP}_{sys}$. Our theoretical predictions are validated with heat flow measurement data obtained at an ice hockey hall in Finland. They are also confronted with technical and cost-related constraints, and implemented by simulations with the pr...
Predicting PVT data for CO2brine mixtures for black-oil simulation of CO2 geological storage
Santos, Juan
Predicting PVT data for CO2brine mixtures for black-oil simulation of CO2 geological storage efficiency of the black-oil approach promote application of black-oil simulation for large-scale geological into geological formations has been considered as a potential method to mitigate climate change. Accurate
Firoozabadi, Abbas
Macro- and Microscale Waterflooding Performances of Crudes which form w/o Emulsions upon Mixing with Brines N. Rezaei and A. Firoozabadi*,, Reservoir Engineering Research Institute, 595 Lytton Avenue, Palo ABSTRACT: We study the micro- and macroscale waterflooding performances of unusual crudes which naturally
Schechter, David S.
, followed by waterflooding, were performed at reservoir conditions to investigate rock wettability. A two Berea and Spraberry cores at reservoir conditions to illustrate the actual process of waterflooding- 31 - 2. INVESTIGATION OF CRUDE OIL/BRINE/ROCK INTERACTION 2.1 STUDY OF WATERFLOODING PROCESS
Hall, David R. (Provo, UT); Pixton, David S. (Lehi, UT); Briscoe, Michael (Lehi, UT); McPherson, James (Sandy, UT)
2007-12-04T23:59:59.000Z
A filter for a drill string comprises a perforated receptacle having an open end and a perforated end and first and second mounting surfaces are adjacent the open end. A transmission element is disposed within each of the first and second mounting surfaces. A capacitor may modify electrical characteristics of an LC circuit that comprises the transmission elements. The respective transmission elements are in communication with each other and with a transmission network integrated into the drill string. The transmission elements may be inductive couplers, direct electrical contacts, or optical couplers. In some embodiments of the present invention, the filter comprises an electronic component. The electronic component may be selected from the group consisting of a sensor, a router, a power source, a clock source, a repeater, and an amplifier.
Not Available
1980-12-01T23:59:59.000Z
The long lead time required for conversion from oil or gas to coal and for development of a synthetic fuel industry dictates that oil and gas must continue to supply the United States with the majority of its energy requirements over the near term. In the interim period, the nation must seek a resource that can be developed quickly, incrementally, and with as few environmental concerns as possible. One option which could potentially fit these requirements is to explore for, drill, and produce unconventional gas: Devonian Shale gas, coal seam gas, gas dissolved in geopressured brines, and gas from tight reservoirs. This report addresses the significance of these sources and the economic and technical conditions under which they could be developed.
Unnatural landscapes in ecology: Generating the spatial distribution of brine spills
Jager, Yetta [ORNL; Efroymson, Rebecca Ann [ORNL; Sublette, K. [University of Tulsa; Ashwood, Tom L [ORNL
2005-01-01T23:59:59.000Z
Quantitative tools are needed to evaluate the ecological effects of increasing petroleum production. In this article, we describe two stochastic models for simulating the spatial distribution of brine spills on a landscape. One model uses general assumptions about the spatial arrangement of spills and their sizes; the second model distributes spills by siting rectangular well complexes and conditioning spill probabilities on the configuration of pipes. We present maps of landscapes with spills produced by the two methods and compare the ability of the models to reproduce a specified spill area. A strength of the models presented here is their ability to extrapolate from the existing landscape to simulate landscapes with a higher (or lower) density of oil wells.
Cosmological consequences of string axions
Kain, Ben [Department of Physics, University of California and Theoretical Physics Group, Bldg. 50A5104, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2006-06-15T23:59:59.000Z
Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the consequences of a measurement of these fluctuations for two additional string axions. We do so independent of any cosmological assumptions. The first axion has been shown to solve the strong CP problem for most compactifications of the heterotic string while the second axion, which does not solve the strong CP problem, obeys a mass formula which is independent of the axion scale. We find that if gravitational waves interpreted as arising from inflation are observed by the PLANCK polarimetry experiment with a Hubble constant during inflation of H{sub inf} > or approx. 10{sup 13} GeV the existence of the first axion is ruled out and the second axion cannot obey the scale independent mass formula. In an appendix we quantitatively justify the often held assumption that temperature corrections to the zero temperature QCD axion mass may be ignored for temperatures T < or approx. {lambda}{sub QCD}.
Cosmological Consequences of String Axions
Kain, Ben
2005-12-15T23:59:59.000Z
Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the consequences of a measurement of these fluctuations for two additional string axions. We do so independent of any cosmological assumptions except for the axions being massless during inflation. The first axion has been shown to solve the strong CP problem for most compactifications of the heterotic string while the second axion, which does not solve the strong CP problem, obeys a mass formula which is independent of the axion scale. We find that if gravitational waves interpreted as arising from inflation are observed by the PLANCK polarimetry experiment with a Hubble constant during inflation of H{sub inf} {approx}> 10{sup 13} GeV the existence of the first axion is ruled out and the second axion cannot obey the scale independent mass formula. In an appendix we quantitatively justify the often held assumption that temperature corrections to the zero temperature QCD axion mass may be ignored for temperatures T {approx}< {Lambda}{sub QCD}.
Energy radiated from a fluctuating selfdual string
Andreas Gustavsson
2005-06-06T23:59:59.000Z
We compute the energy that is radiated from a fluctuating selfdual string in the large $N$ limit of $A_{N-1}$ theory using the AdS-CFT correspondence. We find that the radiated energy is given by a non-local expression integrated over the string world-sheet. We also make the corresponding computation for a charged string in six-dimensional classical electrodynamics, thereby generalizing the Larmor formula for the radiated energy from an accelerated point particle.
Gamma Ray Bursts from Ordinary Cosmic Strings
R. H. Brandenberger; A. T. Sornborger; M. Trodden
1993-02-12T23:59:59.000Z
We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.
String theory: big problem for small size
S. Sahoo
2012-09-25T23:59:59.000Z
String theory is the most promising candidate theory for a unified description of all fundamental forces exist in the nature. It provides a mathematical framework that combine quantum theory with Einstein's general theory of relativity. But due to the extremely small size of strings, nobody has been able to detect it directly in the laboratory till today. In this article, we have presented a general introduction to string theory.
Brane World Models Need Low String Scale
Antoniadis, Ignatios; Calmet, Xavier
2011-01-01T23:59:59.000Z
Models with large extra dimensions offer the possibility of the Planck scale being of order the electroweak scale, thus alleviating the gauge hierarchy problem. We show that these models suffer from a breakdown of unitarity at around three quarters of the low effective Planck scale. An obvious candidate to fix the unitarity problem is string theory. We therefore argue that it is necessary for the string scale to appear below the effective Planck scale and that the first signature of such models would be string resonances. We further translate experimental bounds on the string scale into bounds on the effective Planck scale.
Singularities and Closed String Tachyons
Silverstein, Eva; /SLAC /Stanford U., Phys. Dept.
2006-03-17T23:59:59.000Z
A basic problem in gravitational physics is the resolution of spacetime singularities where general relativity breaks down. The simplest such singularities are conical singularities arising from orbifold identifications of flat space, and the most challenging are spacelike singularities inside black holes (and in cosmology). Topology changing processes also require evolution through classically singular spacetimes. I briefly review how a phase of closed string tachyon condensate replaces, and helps to resolve, basic singularities of each of these types. Finally I discuss some interesting features of singularities arising in the small volume limit of compact negatively curved spaces and the emerging zoology of spacelike singularities.
) is capable of reducing atmospheric emissions of greenhouse gases from coal or gas fired power plants or supercritical phase, as water-alternating gas cycles, or as carbonated brine. These result in different
Woods, Edward Andrew
1982-01-01T23:59:59.000Z
30%. Videophotography and doppler-based rangefinder measurements were used to map the seep area. Current measurements of the brine stream were made using a Savonius rotor attached to the manipulator Analysis of data was carried out using...
Wiggly cosmic strings accrete dark energy
Pedro F. Gonzalez-Diaz; Jose A. Jimenez Madrid
2005-06-29T23:59:59.000Z
This paper deals with a study of the cylindrically symmetric accretion of dark energy with equation of state $p=w\\rho$ onto wiggly straight cosmic strings. We have obtained that when $w>-1$ the linear energy density in the string core gradually increases tending to a finite maximum value as time increases for all considered dark energy models. On the regime where the dominant energy condition is violated all such models predict a steady decreasing of the linear energy density of the cosmic strings as phantom energy is being accreted. The final state of the string after such an accretion process is a wiggleless defect. It is argued however that if accreation of phantom energy would proceed by successive quantum steps then the defect would continue losing linear energy density until a minimum nonzero value which can be quite smaller than that corresponding to the unperturbed string.
Vibration monitoring system for drill string
Wassell, M.E.
1993-07-13T23:59:59.000Z
A vibration monitoring system is described for use in monitoring lateral and torsional vibrations in a drill string comprising: a drill string component having an outer surface; first accelerometer means A[sub 1] for measuring tangential acceleration; second accelerometer means A[sub 2] for measuring tangential acceleration; third accelerometer means A[sub 3] for measuring tangential acceleration; said first, second and third accelerometer means A[sub 1], A[sub 2] and A[sub 3] being mounted in said drill string component and being spaced from one another to measure acceleration forces on said drill string component tangentially with respect to the outer surface of said component wherein said first, second and third accelerometer means are adapted to measure and distinguish between lateral and torsional vibrations exerted on said drill string component.
Davidson, Casie L.; Watson, David J.; Dooley, James J.; Dahowski, Robert T.
2014-01-01T23:59:59.000Z
Pressure increases attendant with CO2 injection into the subsurface drive many of the risk factors associated with commercial-scale CCS projects, impacting project costs and liabilities in a number of ways. The area of elevated pressure defines the area that must be characterized and monitored; pressure drives fluid flow out of the storage reservoir along higher-permeability pathways that might exist through the caprock into overlying aquifers or hydrocarbon reservoirs; and pressure drives geomechanical changes that could potentially impact subsurface infrastructure or the integrity of the storage system itself. Pressure also limits injectivity, which can increase capital costs associated with installing additional wells to meet a given target injection rate. The ability to mitigate pressure increases in storage reservoirs could have significant value to a CCS project, but these benefits are offset by the costs of the pressure mitigation technique itself. Of particular interest for CO2 storage operators is the lifetime cost of implementing brine extraction at a CCS project site, and the relative value of benefits derived from the extraction process. This is expected to vary from site to site and from one implementation scenario to the next. Indeed, quantifying benefits against costs could allow operators to optimize their return on project investment by calculating the most effective scenario for pressure mitigation. This work builds on research recently submitted for publication by the authors examining the costs and benefits of brine extraction across operational scenarios to evaluate the effects of fluid extraction on injection rate to assess the cost effectiveness of several options for reducing the number of injection wells required. Modeling suggests that extracting at 90% of the volumetric equivalent of injection rate resulted in a 1.8% improvement in rate over a non-extraction base case; a four-fold increase in extraction rate results in a 7.6% increase in injection rate over the no-extraction base case. However, the practical impacts on capital costs suggest that this strategy is fiscally ineffective when evaluated solely on this metric, with extraction reducing injection well needs by only one per 56 (1x case) or one per 13 (4x case).
Bose-Einstein condensate strings
Tiberiu Harko; Matthew J. Lake
2015-01-17T23:59:59.000Z
We consider the possible existence of gravitationally bound general relativistic strings consisting of Bose-Einstein condensate (BEC) matter which is described, in the Newtonian limit, by the zero temperature time-dependent nonlinear Schr\\"odinger equation (the Gross-Pitaevskii equation), with repulsive interparticle interactions. In the Madelung representation of the wave function, the quantum dynamics of the condensate can be formulated in terms of the classical continuity equation and the hydrodynamic Euler equations. In the case of a condensate with quartic nonlinearity, the condensates can be described as a gas with two pressure terms, the interaction pressure, which is proportional to the square of the matter density, and the quantum pressure, which is without any classical analogue though, when the number of particles in the system is high enough, the latter may be neglected. By assuming cylindrical symmetry, we analyze the physical properties of the BEC strings in both the interaction pressure and quantum pressure dominated limits, by numerically integrating the gravitational field equations. In this way we obtain a large class of stable stringlike astrophysical objects, whose basic parameters (mass density and radius) depend sensitively on the mass and scattering length of the condensate particle, as well as on the quantum pressure of the Bose-Einstein gas.
Matherly, R.M.; Jiao, J. [Baker Performance Chemicals, Houston, TX (United States); Blumer, D.J. [ARCO Alaska Inc., Anchorage, AK (United States); Ryman, J.S. [Baker Performance Chemicals, Anchorage, AK (United States)
1995-12-01T23:59:59.000Z
The classical method for the determination of corrosion inhibitors in oilfield brines is the dye transfer method. Within this method are many variations which the analyst may use to determine the amount of corrosion inhibitor in either water or crude oil. These methods, however, suffer from many interferences which result in both false positive and negatives for corrosion inhibitor content. These methods essentially detect all amines as corrosion inhibitors. Improved high pressure liquid chromatography (HPLC) methods have been developed for the analysis of quaternary salt type corrosion inhibitors in brine waters, however, these methods do not appear to work in crude oil or for other forms of corrosion inhibitors such as the imidazolines, and amido-amines. This paper presents a method for the quantitative analysis of the imidazoline and amido-amine type corrosion inhibitors in both oilfield water and crude oil samples by HPLC. The corrosion inhibitor of interest is first separated from the matrix on a small column, then derivatized to form a product which is both sensitive and selective on a fluorescence detector. Detection limits for imidazolines are around 0.2 mg/L, amides and amines are similar. The advantage of this procedure is it can be used to determine the amount of corrosion inhibitor in both oil and brine water phases as well as on solid surfaces.
QFT, String Temperature and the String Phase of de Sitter Space-time
Medrano, M R
1999-01-01T23:59:59.000Z
The density of mass levels \\rho(m) and the critical temperature for strings in de Sitter space-time are found. QFT and string theory in de Sitter space are compared. A `Dual'-transform is introduced which relates classical to quantum string lengths, and more generally, QFT and string domains. Interestingly, the string temperature in De Sitter space turns out to be the Dual transform of the QFT-Hawking-Gibbons temperature. The back reaction problem for strings in de Sitter space is addressed selfconsistently in the framework of the `string analogue' model (or thermodynamical approach), which is well suited to combine QFT and string study.We find de Sitter space-time is a self-consistent solution of the semiclassical Einstein equations in this framework. Two branches for the scalar curvature R(\\pm) show up: a classical, low curvature solution (-), and a quantum high curvature solution (+), enterely sustained by the strings. There is a maximal value for the curvature R_{\\max} due to the string back reaction. Int...
Effects of overlapping strings in pp collisions
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bierlich, Christian; Gustafson, Gösta; Lönnblad, Leif; Tarasov, Andrey
2015-03-01T23:59:59.000Z
In models for hadron collisions based on string hadronization, the strings are usually treated as independent, allowing no interaction between the confined colour fields. In studies of nucleus collisions it has been suggested that strings close in space can fuse to form "colour ropes." Such ropes are expected to give more strange particles and baryons, which also has been suggested as a signal for plasma formation. Overlapping strings can also be expected in pp collisions, where usually no phase transition is expected. In particular at the high LHC energies the expected density of strings is quite high. To investigate possiblemore »effects of rope formation, we present a model in which strings are allowed to combine into higher multiplets, giving rise to increased production of baryons and strangeness, or recombine into singlet structures and vanish. Also a crude model for strings recombining into junction structures is considered, again giving rise to increased baryon production. The models are implemented in the DIPSY MC event generator, using PYTHIA8 for hadronization, and comparison to pp minimum bias data, reveals improvement in the description of identified particle spectra.« less
Effects of Overlapping Strings in pp Collisions
Christian Bierlich; Gösta Gustafson; Leif Lönnblad; Andrey Tarasov
2015-02-13T23:59:59.000Z
In models for hadron collisions based on string hadronization, the strings are usually treated as independent, allowing no interaction between the confined colour fields. In studies of nucleus collisions it has been suggested that strings close in space can fuse to form "colour ropes". Such ropes are expected to give more strange particles and baryons, which also has been suggested as a signal for plasma formation. Overlapping strings can also be expected in pp collisions, where usually no phase transition is expected. In particular at the high LHC energies the expected density of strings is quite high. To investigate possible effects of rope formation, we present a model in which strings are allowed to combine into higher multiplets, giving rise to increased production of baryons and strangeness, or recombine into singlet structures and vanish. Also a crude model for strings recombining into junction structures is considered, again giving rise to increased baryon production. The models are implemented in the DIPSY MC event generator, using PYTHIA 8 for hadronization, and comparison to pp minimum bias data, reveals improvement in the description of identified particle spectra.
Effects of overlapping strings in pp collisions
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bierlich, Christian [Lund University; Gustafson, Gösta [Lund University; Lönnblad, Leif [Lund University; Tarasov, Andrey [JLAB
2015-03-01T23:59:59.000Z
In models for hadron collisions based on string hadronization, the strings are usually treated as independent, allowing no interaction between the confined colour fields. In studies of nucleus collisions it has been suggested that strings close in space can fuse to form "colour ropes." Such ropes are expected to give more strange particles and baryons, which also has been suggested as a signal for plasma formation. Overlapping strings can also be expected in pp collisions, where usually no phase transition is expected. In particular at the high LHC energies the expected density of strings is quite high. To investigate possible effects of rope formation, we present a model in which strings are allowed to combine into higher multiplets, giving rise to increased production of baryons and strangeness, or recombine into singlet structures and vanish. Also a crude model for strings recombining into junction structures is considered, again giving rise to increased baryon production. The models are implemented in the DIPSY MC event generator, using PYTHIA8 for hadronization, and comparison to pp minimum bias data, reveals improvement in the description of identified particle spectra.
Strings and their compactification from the particle viewpoint
Slansky, R.
1986-01-01T23:59:59.000Z
A series of four lectures is given which deals with the particle formulation of string theory. An introductory lecture is given on where the idea of strings comes from and what strings are. An introduction is given to simple Lie algebras and their representations. Compactified strings and the heterotic theories are discussed, showing how infinite-dimensional Kac-Moody affine algebras can be spectrum generating algebras in (open) string theories. The spectrum of excited states of the heterotic string is examined, and comments are made on representations of affine algebras. Some aspects are shown of the algebraic structure of compactified closed bosonic strings. (LEW)
Semiclassical analysis of string-gauge duality on noncommutative space
Rashkov, R.C.; Viswanathan, K.S.; Yang Yi [Department of Physics, Sofia University, 1164 Sofia (Bulgaria); Department of Physics, Simon Fraser University, Burnaby, British Columbia (Canada); Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China)
2004-10-15T23:59:59.000Z
We use semiclassical methods to study closed strings in the modified AdS{sub 5}xS{sup 5} background with constant B fields. The pointlike closed strings and the stretched closed strings rotating around the big circle of S{sup 5} are considered. Quantization of these closed string leads to a time-dependent string spectrum, which we argue corresponds to the renormalization-group flow of the dual noncommutative Yang-Mills theory.
A Proposal for Altering the Unification Scale in String Theory
Shyamoli Chaudhuri
2005-02-18T23:59:59.000Z
An ensemble of short open strings in equilibrium with the heat bath provided by the Euclidean worldvolume of a stack of Dbranes undergoes a thermal phase transition to a long string phase. The transition temperature is just below the string scale. We point out that this phenomenon provides a simple mechanism within open and closed string theories for altering the strong-electro-weak coupling unification scale relative to the fundamental closed string mass scale in spacetimes with external electromagnetic background.
Mining Energy from a Black Hole by Strings
V. Frolov; D. Fursaev
2001-05-10T23:59:59.000Z
We discuss how cosmic strings can be used to mine energy from black holes. A string attached to the black hole gives rise to an additional channel for the energy release. It is demonstrated that when a string crosses the event horizon, its transverse degrees of freedom are thermally excited and thermal string perturbations propagate along the string to infinity. The internal metric induced on the 2D worldsheet of the static string crossing the horizon describes a 2D black hole. For this reason thermal radiation of string excitations propagating along the string can be interpreted as Hawking radiation of the 2D black hole. It is shown that the rate of energy emission through the string channel is of the same order of magnitude as the bulk radiation of the black hole. Thus, for N strings attached to the black hole the efficiency of string channels is increased by factor N. We discuss restrictions on N which exist because of the finite thickness of strings, the gravitational backreaction and quantum fluctuations. Our conclusion is that the energy emission rate by strings can be increased as compared to the standard emission in the bulk by the factor 10^3 for GUT strings and up to the factor 10^{31} for electroweak strings.
Bohner, Martin
of water in which two pounds of salt has been dissolved. Brine with 1.5 pound of salt per gallon enters
Effect of cosmic string on spin dynamics
Debashree Chowdhury; B. Basu
2014-11-07T23:59:59.000Z
In the present paper, we have investigated the role of cosmic string on spin current and Hall electric field. Due to the background cosmic string, the modified electric field of the system generates renormalized spin orbit coupling, which induces a modified non-Abelian gauge field. The defect causes a change in the AB and AC phases appearing due to the modified electromagnetic field. In addition, for a time varying electric field we perform explicit analytic calculations to derive the exact form of spin electric field and spin current, which is defect parameter dependent and of oscillating type. Furthermore, in an asymmetric crystal within the Drude model approach we investigate the dependence of the cosmic string parameters on cosmic string induced Hall electric field.
Fractal Strings and Multifractal Zeta Functions
Lapidus, Michel L.; Lévy-Véhel, Jacques; Rock, John A.
2009-01-01T23:59:59.000Z
decompositions of Moran fractals. Adv. Math. 92, 196–236 (Probab. 12, 8. Falconer, K. : Fractal Geometry—MathematicalB.M. , Lapidus, M.L. : Random fractal strings: their zeta
Two-dimensional QCD and strings
D. J. Gross; W. Taylor
1993-11-12T23:59:59.000Z
A review is given of recent research on two-dimensional gauge theories, with particular emphasis on the equivalence between these theories and certain string theories with a two-dimensional target space. Some related open problems are discussed.
Introduction to string and superstring theory II
Peskin, M.E.
1987-03-01T23:59:59.000Z
Conformal field theory is reviewed, then conformal invariance is used to rederive the basic results on the embedding dimensionality for bosonic and fermionic strings. The spectrum of the bosonic and the computation of scattering amplitudes are discussed. The formalism used is extended to clarify the origin of Yang-Mills gauge invariance in the open bosonic string theory. The question of the general-coordinate gauge invariance of string theory is addressed, presenting two disparate viewpoints on this question. A brief introduction is then given of the reduction from the idealized string theory in 10 extended dimensions to more realistic solutions in which all but 4 of these dimensions are compactified. The state of knowledge about the space-time supersymmetry of the superstring from the covariant viewpoint is outlined. An approach for identifying possible 6-dimensional spaces which might represent the form of the compact dimensions is discussed, and the orbifold scheme of compactification is presented. 77 refs., 18 figs. (LEW)
Exact sum rules for inhomogeneous strings
Amore, Paolo, E-mail: paolo.amore@gmail.com
2013-11-15T23:59:59.000Z
We derive explicit expressions for the sum rules of the eigenvalues of inhomogeneous strings with arbitrary density and with different boundary conditions. We show that the sum rule of order N may be obtained in terms of a diagrammatic expansion, with (N?1)!/2 independent diagrams. These sum rules are used to derive upper and lower bounds to the energy of the fundamental mode of an inhomogeneous string; we also show that it is possible to improve these approximations taking into account the asymptotic behavior of the spectrum and applying the Shanks transformation to the sequence of approximations obtained to the different orders. We discuss three applications of these results. -- Highlights: •We derive an explicit expression for the sum rules of an inhomogeneous string. •We obtain a diagrammatic representation for the sum rules of a given order. •We obtain precise bounds on the lowest eigenvalue of the string.
Axions from cosmic string and wall decay
Hagmann, C A
2010-03-10T23:59:59.000Z
If inflation occurred with a reheat temperature > T{sub PQ}, axions from the decay of global axion strings and domain walls would make an important contribution to the cosmological energy density, comparable to that from vacuum misalignment. Several groups have numerically studied the evolution of axion strings and walls in the past, however substantial uncertainties remain in their contribution to the present density {Omega}{sub a,string+wall} {approx} 1-100 (f{sub a}/10{sup 12} GeV){sup 7/6}, where f{sub a} is the axion decay constant. I will describe the numerical methods used in our simulations and show results for several string and wall configurations.
Axions from cosmic string and wall decay
Hagmann, Chris [Lawrence Livermore National Laboratory, L-59, 7000 East Ave, Livermore, CA (United States)
2010-08-30T23:59:59.000Z
If inflation occurred with a reheat temperature > T{sub PQ}, axions from the decay of global axion strings and domain walls would make an important contribution to the cosmological energy density, comparable to that from vacuum misalignment. Several groups have numerically studied the evolution of axion strings and walls in the past, however substantial uncertainties remain in their contribution to the present density {Omega}{sub a,string+wall{approx}}1-100(f{sub a}/10{sup 12} GeV){sup 7/6}, where f{sub a} is the axion decay constant. I will describe the numerical methods used in our simulations and show results for several string and wall configurations.
String field theory and tachyon dynamics
Yang, Haitang, Ph. D. Massachusetts Institute of Technology
2006-01-01T23:59:59.000Z
In this thesis we present some works done during my doctoral studies. These results focus on two directions. The first one is motivated by tachyon dynamics in open string theory. We calculate the stress tensors for the ...
David B. Burnett; Mustafa Siddiqui
2006-12-29T23:59:59.000Z
Management and disposal of produced water is one of the most important problems associated with oil and gas (O&G) production. O&G production operations generate large volumes of brine water along with the petroleum resource. Currently, produced water is treated as a waste and is not available for any beneficial purposes for the communities where oil and gas is produced. Produced water contains different contaminants that must be removed before it can be used for any beneficial surface applications. Arid areas like west Texas produce large amount of oil, but, at the same time, have a shortage of potable water. A multidisciplinary team headed by researchers from Texas A&M University has spent more than six years is developing advanced membrane filtration processes for treating oil field produced brines The government-industry cooperative joint venture has been managed by the Global Petroleum Research Institute (GPRI). The goal of the project has been to demonstrate that treatment of oil field waste water for re-use will reduce water handling costs by 50% or greater. Our work has included (1) integrating advanced materials into existing prototype units and (2) operating short and long-term field testing with full size process trains. Testing at A&M has allowed us to upgrade our existing units with improved pre-treatment oil removal techniques and new oil tolerant RO membranes. We have also been able to perform extended testing in 'field laboratories' to gather much needed extended run time data on filter salt rejection efficiency and plugging characteristics of the process train. The Program Report describes work to evaluate the technical and economical feasibility of treating produced water with a combination of different separation processes to obtain water of agricultural water quality standards. Experiments were done for the pretreatment of produced water using a new liquid-liquid centrifuge, organoclay and microfiltration and ultrafiltration membranes for the removal of hydrocarbons from produced water. The results of these experiments show that hydrocarbons from produced water can be reduced from 200 ppm to below 29 ppm level. Experiments were also done to remove the dissolved solids (salts) from the pretreated produced water using desalination membranes. Produced water with up to 45,000 ppm total dissolved solids (TDS) can be treated to agricultural water quality water standards having less than 500 ppm TDS. The Report also discusses the results of field testing of various process trains to measure performance of the desalination process. Economic analysis based on field testing, including capital and operational costs, was done to predict the water treatment costs. Cost of treating produced water containing 15,000 ppm total dissolved solids and 200 ppm hydrocarbons to obtain agricultural water quality with less than 200 ppm TDS and 2 ppm hydrocarbons range between $0.5-1.5 /bbl. The contribution of fresh water resource from produced water will contribute enormously to the sustainable development of the communities where oil and gas is produced and fresh water is a scarce resource. This water can be used for many beneficial purposes such as agriculture, horticulture, rangeland and ecological restorations, and other environmental and industrial application.
John, Han [Los Alamos National Laboratory; Carey, James W [Los Alamos National Laboratory; Zhang, Jinsuo [Los Alamos National Laboratory
2010-10-07T23:59:59.000Z
The geologic sequestration of CO{sub 2} is a proposed method to limit greenhouse gas emissions and has been the subject of many studies in the last decade. Wellbore systems achieve isolation of the storage reservoir through a combination of steel (generally carbon steel) and Portland cement. CO{sub 2} leakage along the steel-cement interface has the potential to accelerate corrosion. We conduct experiments to assess the corrosion risk at cement-steel interface under in situ wellbore conditions. Wellbore interfaces were simulated by assemblies constructed of J55 mild steel and Portland class G (Epoxy was used in this study to separate) cement and corrosion was investigated in supercritical CO{sub 2} saturated brines, (NaCl = 1 wt%) at T = 50 C, pCO{sub 2} = 1200 psi with interface gap size = 100 {micro}m and {infinity} (open surface). The experiments were carried out in a high-pressure, 1.8 L autoclave. The corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance and electrochemical impedance spectroscopy techniques. The corrosion scales were analyzed using secondary electron microscopy, back scattering electron microscopy, energy dispersive spectroscopy and x-ray diffraction. Corrosion rates decreased as time with or without interface gap. In this case corrosion rates are controlled by scale protectivity through the interface gap. Scaled steel corrosion rates were two orders of magnitude less compared with fresh steel. The corrosion scale is pseudo crystalline at the open interface. Well-crystallized scale was observed at interface gap sizes 100 {micro}m. All corrosion scales were composed of iron carbonates.
Compressed Indexes for Approximate String Matching
Sung, Wing-Kin Ken"
Compressed Indexes for Approximate String Matching Ho-Leung Chan1 Tak-Wah Lam1, Wing-Kin Sung2 Siu the index space to O(n log n). Huynh et al. [10] and Lam et al. [11] further compressed the index to O,wongss}@comp.nus.edu.sg Abstract. We revisit the problem of indexing a string S[1..n] to support searching all substrings
Cosmological Constant and Axions in String Theory
Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC
2006-08-18T23:59:59.000Z
String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.
Thermal Duality and the String Canonical Ensemble
Shyamoli Chaudhuri
2005-10-21T23:59:59.000Z
We derive the free energies of both the closed heterotic, and the unoriented, open and closed, type I string ensembles, consistent with the thermal (Euclidean T-duality) transformations on the String/M Duality Web. A crucial role is played by a temperature dependent Wilson line wrapping Euclidean time, responsible for the spontaneous breaking of supersymmetry at finite temperature while eliminating thermal tachyons, and determined uniquely by thermal duality. Conversely, we can show that the absence of a Yang-Mills gauge sector precludes the possibility of an equilibrium type II canonical ensemble prior to the introduction of background Dbranes or fluxes. As a consistency check, we verify that our results for the string free energy always reproduce the T^{10} growth expected in the low energy field theory limits while displaying a dramatically slower T^2 growth at temperatures above the string scale. We present both the low and high temperature expansions for the one-loop heterotic and type I string free energies, results which follow from an explicit term-by-term evaluation of the modular integrals in the string mass level expansion.
BookProcessing public Book(string tit, string au, double pr, bool av)
Krupski, Vladimir Nickolayevich
Methods BookDB ProcessAllAvail BookProcessing Delegate b private List list; public BookDB() { list } public void ProcessAllAvail(BookProcessing Action) { foreach (Book b in list) { if (b.avail) { Action Author { get { return author;} } private string author; public class Book { private string title; private
Accidental inflation in string theory
Linde, Andrei; Westphal, Alexander, E-mail: alinde@stanford.edu, E-mail: awestpha@stanford.edu [Department of Physics, Stanford University, Stanford, CA 94305-4060 (United States)
2008-03-15T23:59:59.000Z
We show that inflation in type IIB string theory driven by the volume modulus can be realized in the context of the racetrack-based Kallosh-Linde model (KL) of moduli stabilization. Inflation here arises through the volume modulus slow-rolling down from a flat hilltop or inflection point of the scalar potential. This situation can be quite generic in the landscape, where by uplifting one of the two adjacent minima one can turn the barrier either into a flat saddle point or into an inflection point supporting eternal inflation. The resulting spectral index is tunable in the range of 0.93{approx}
Low energy 2+1 string gravity; black hole solutions
A. A. Garcia Diaz; G. Gutierrez Cano
2014-12-17T23:59:59.000Z
In this report a detailed derivation of the dynamical equations for an n dimensional heterotic string theory of the Horowitz type is carried out in the string frame and in the Einstein frame too. In particular, the dynamical equations of the three dimensional string theory are explicitly given. The relation of the Horowitz Welch and Horne Horowitz string black hole solution is exhibited. The Chan Mann charged dilaton solution is derived and the subclass of string solutions field is explicitly identified. The stationary generalization, via SL(2;R) transformations, of the static (2+1) Horne Horowitz string black hole solution is given.
DeRouen, L.R.; Hann, R.W.; Casserly, D.M.; Giammona, C.; Lascara, V.J. (eds.)
1983-02-01T23:59:59.000Z
This project centers around the Strategic Petroleum Site (SPR) known as the West Hackberry salt dome which is located in southwestern Louisiana, and which is designed to store 241 million barrels of crude oil. Oil storage caverns are formed by injecting water into salt deposits, and pumping out the resulting brine. Studies described in this report were designed as follow-on studies to three months of pre-discharge characterization work, and include data collected during the first year of brine leaching operations. The objectives were to: (1) characterize the environment in terms of physical, chemical and biological attributes; (2) determine if significant adverse changes in ecosystem productivity and stability of the biological community are occurring as a result of brine discharge; and (3) determine the magnitude of any change observed. Contents of Volume II include: introduction; physical oceanography; estuarine hydrology and hydrography; analysis of discharge plume; and water and sediment quality.
STOELZEL,D.M.; O'BRIEN,D.G.; GARNER,J.W.; HELTON,JON CRAIG; JOHNSON,J.D.; SCOTT,L.N.
2000-05-19T23:59:59.000Z
The following topics related to the treatment of direct brine releases to the surface environment in the 1996 performance assessment for the Waste Isolation Pilot Plant (WIPP) are presented (1) mathematical description of models, (2) uncertainty and sensitivity analysis results arising from subjective (i.e., epistemic) uncertainty for individual releases, (3) construction of complementary cumulative distribution functions (CCDFs) arising from stochastic (i.e., aleatory) uncertainty, and (4) uncertainty and sensitivity analysis results for CCDFs. The presented analyses indicate that direct brine releases do not constitute a serious threat to the effectiveness of the WIPP as a disposal facility for transuranic waste. Even when the effects of uncertain analysis inputs are taken into account, the CCDFs for direct brine releases fall substantially to the left of the boundary line specified in the US Environmental Protection Agency's standard for the geologic disposal of radioactive waste (4O CFR 191.40 CFR 194).
Modifications of Carbonate Fracture Hydrodynamic Properties by CO{sub 2}-Acidified Brine Flow
Deng, Hang; Ellis, Brian R.; Peters, Catherine A.; Fitts, Jeffrey P.; Crandall, Dustin; Bromhal, Grant S.
2013-08-01T23:59:59.000Z
Acidic reactive flow in fractures is relevant in subsurface activities such as CO{sub 2} geological storage and hydraulic fracturing. Understanding reaction-induced changes in fracture hydrodynamic properties is essential for predicting subsurface flows such as leakage, injectability, and fluid production. In this study, x-ray computed tomography scans of a fractured carbonate caprock were used to create three dimensional reconstructions of the fracture before and after reaction with CO{sub 2}-acidified brine (Ellis et al., 2011, Greenhouse Gases: Sci. Technol., 1:248-260). As expected, mechanical apertures were found to increase substantially, doubling and even tripling in some places. However, the surface geometry evolved in complex ways including ‘comb-tooth’ structures created from preferential dissolution of calcite in transverse sedimentary bands, and the creation of degraded zones, i.e. porous calcite-depleted areas on reacted fracture surfaces. These geometric alterations resulted in increased fracture roughness, as measured by surface Z{sub 2} parameters and fractal dimensions D{sub f}. Computational fluid dynamics (CFD) simulations were conducted to quantify the changes in hydraulic aperture, fracture transmissivity and permeability. The results show that the effective hydraulic apertures are smaller than the mechanical apertures, and the changes in hydraulic apertures are nonlinear. Overestimation of flow rate by a factor of two or more would be introduced if fracture hydrodynamic properties were based on mechanical apertures, or if hydraulic aperture is assumed to change proportionally with mechanical aperture. The differences can be attributed, in part, to the increase in roughness after reaction, and is likely affected by contiguous transverse sedimentary features. Hydraulic apertures estimated by the 1D statistical model and 2D local cubic law (LCL) model are consistently larger than those calculated from the CFD simulations. In addition, a novel ternary segmentation method was devised to handle the degraded zones, allowing for a bounding analysis of the effects on hydraulic properties. We found that the degraded zones account for less than 15% of the fracture volume, but cover 70% to 80% of the fracture surface. When the degraded zones are treated as part of the fracture, the fracture transmissivities are two to four times larger because the fracture surfaces after reaction are not as rough as they would be if one considers the degraded zone as part of the rock. Therefore, while degraded zones created during geochemical reactions may not significantly increase mechanical aperture, this type of feature cannot be ignored and should be treated with prudence when predicting fracture hydrodynamic properties.
Perturbative String Thermodynamics near Black Hole Horizons
Thomas G. Mertens; Henri Verschelde; Valentin I. Zakharov
2014-10-29T23:59:59.000Z
We provide further computations and ideas to the problem of near-Hagedorn string thermodynamics near (uncharged) black hole horizons, building upon our earlier work JHEP 1403 (2014) 086. The relevance of long strings to one-loop black hole thermodynamics is emphasized. We then provide an argument in favor of the absence of $\\alpha'$-corrections for the (quadratic) heterotic thermal scalar action in Rindler space. We also compute the large $k$ limit of the cigar orbifold partition functions (for both bosonic and type II superstrings) which allows a better comparison between the flat cones and the cigar cones. A discussion is made on the general McClain-Roth-O'Brien-Tan theorem and on the fact that different torus embeddings lead to different aspects of string thermodynamics. The black hole/string correspondence principle for the 2d black hole is discussed in terms of the thermal scalar. Finally, we present an argument to deal with arbitrary higher genus partition functions, suggesting the breakdown of string perturbation theory (in $g_s$) to compute thermodynamical quantities in black hole spacetimes.
Nonperturbative Type I-I' String Theory
Shyamoli Chaudhuri
2005-07-24T23:59:59.000Z
We propose a nonperturbative framework for the O(32) type I open and closed string theory. The short distance degrees of freedom are bosonic and fermionic hermitian matrices belonging respectively to the adjoint and fundamental representations of the special unitary group SU(N). We identify a closed matrix algebra at finite N which corresponds to the Lorentz, gauge, and supersymmetry algebras of the large N continuum limit. The planar reduction of our matrix theory coincides with the low energy spacetime effective action of the d=10 type I O(32) unoriented open and closed string theory. We show that matrix T-duality transformations can yield a nonperturbative framework for the T-dual type I' closed string theory with 32 D8branes. We show further that under a strong-weak coupling duality transformation the large N reduced action coincides with the low energy spacetime effective action of the d=10 heterotic string, an equivalence at leading order in the inverse string tension and with either gauge group Spin(32)/Z2 or E8xE8. Our matrix formalism has the potential of providing a nonperturbative framework encapsulating all of the weak coupling limits of M theory.
Gledhill, Dwight Kuehl
2006-08-16T23:59:59.000Z
injection of CO2. This study measured calcite solubility and dissolution rates in geologically relevant Na-Ca-Mg-Cl synthetic brines (35 to 200 g L-1 TDS). In brines < 50 g L-1 TDS, the EQPITZER calculated calcium carbonate ion activity product (IAP...
Charles Swann; John Matthews; Rick Ericksen; Joel Kuszmaul
2004-03-01T23:59:59.000Z
Naturally occurring radioactive materials (NORM) are known to be produced as a byproduct of hydrocarbon production in Mississippi. The presence of NORM has resulted in financial losses to the industry and continues to be a liability as the NORM-enriched scales and scale encrusted equipment is typically stored rather than disposed of. Although the NORM problem is well known, there is little publically available data characterizing the hazard. This investigation has produced base line data to fill this informational gap. A total of 329 NORM-related samples were collected with 275 of these samples consisting of brine samples. The samples were derived from 37 oil and gas reservoirs from all major producing areas of the state. The analyses of these data indicate that two isotopes of radium ({sup 226}Ra and {sup 228}Ra) are the ultimate source of the radiation. The radium contained in these co-produced brines is low and so the radiation hazard posed by the brines is also low. Existing regulations dictate the manner in which these salt-enriched brines may be disposed of and proper implementation of the rules will also protect the environment from the brine radiation hazard. Geostatistical analyses of the brine components suggest relationships between the concentrations of {sup 226}Ra and {sup 228}Ra, between the Cl concentration and {sup 226}Ra content, and relationships exist between total dissolved solids, BaSO{sub 4} saturation and concentration of the Cl ion. Principal component analysis points to geological controls on brine chemistry, but the nature of the geologic controls could not be determined. The NORM-enriched barite (BaSO{sub 4}) scales are significantly more radioactive than the brines. Leaching studies suggest that the barite scales, which were thought to be nearly insoluble in the natural environment, can be acted on by soil microorganisms and the enclosed radium can become bioavailable. This result suggests that the landspreading means of scale disposal should be reviewed. This investigation also suggests 23 specific components of best practice which are designed to provide a guide to safe handling of NORM in the hydrocarbon industry. The components of best practice include both worker safety and suggestions to maintain waste isolation from the environment.
Zhou, X.; Morrow, N.R.; Ma, S.
1996-12-31T23:59:59.000Z
Previous studies of crude oil/brine/rock (COBR) and related ensembles showed that wettability and its effect on oil recovery depend on numerous complex interactions. In the present work, the wettability of COBR ensembles prepared using Prudhoe Bay crude oil, a synthetic formation brine, and Berea Sandstone was varied by systematic change in initial water saturation and length of aging time at reservoir temperature (88 C). All displacement tests were run at ambient temperature. Various degrees of water wetness were achieved and quantified by a modified Amott wettability index to water, the relative pseudo work of imbibition, and a newly defined apparent advancing dynamic contact angle. Pairs of spontaneous imbibition (oil recovery by spontaneous imbibition of water) and waterflood (oil recovery vs. pore volumes of water injected) curves were measured for each of the induced wetting states. Several trends were observed. Imbibition rate, and hence water wetness, decreased with increase in aging time and with decrease in initial water saturation. Breakthrough recoveries and final oil recovery by waterflooding increased with decrease in water wetness. Correlations between water wetness and oil recovery by waterflooding and spontaneous imbibition are presented.
Not Available
1993-09-01T23:59:59.000Z
The Department of Energy (DOE) has prepared an environmental assessment (EA), DOE/EA-0804, for the proposed replacement of a deteriorated brine disposal pipeline from the Strategic Petroleum Reserve (SPR) Bryan Mound storage facility in Brazoria County, Texas, into the Gulf of Mexico. In addition, the ocean discharge outfall would be moved shoreward by locating the brine diffuser at the end of the pipeline 3.5 miles offshore at a minimum depth of 30 feet. The action would occur in a floodplain and wetlands; therefore, a floodplain/wetlands assessment has been prepared in conjunction with this EA. Based on the analyses in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969 (42 USC. 4321, et seg.). Therefore, the preparation of an Environmental Impact Statement (EIS) is not required, and the Department is issuing this Finding of No Significant Impact (FONSI). This FONSI also includes a Floodplain Statement of Findings in accordance with 10 CFR Part 1022.
Fractal Strings and Multifractal Zeta Functions
Michel L. Lapidus; Jacques Levy Vehel; John A. Rock
2009-02-09T23:59:59.000Z
For a Borel measure on the unit interval and a sequence of scales that tend to zero, we define a one-parameter family of zeta functions called multifractal zeta functions. These functions are a first attempt to associate a zeta function to certain multifractal measures. However, we primarily show that they associate a new zeta function, the topological zeta function, to a fractal string in order to take into account the topology of its fractal boundary. This expands upon the geometric information garnered by the traditional geometric zeta function of a fractal string in the theory of complex dimensions. In particular, one can distinguish between a fractal string whose boundary is the classical Cantor set, and one whose boundary has a single limit point but has the same sequence of lengths as the complement of the Cantor set. Later work will address related, but somewhat different, approaches to multifractals themselves, via zeta functions, partly motivated by the present paper.
Relativistic elasticity of rigid rods and strings
Jose Natario
2014-09-30T23:59:59.000Z
We show that the equation of motion for a rigid one-dimensional elastic body (i.e. a rod or string whose speed of sound is equal to the speed of light) in a two-dimensional spacetime is simply the wave equation. We then solve this equation in a few simple examples: a rigid rod colliding with an unmovable wall, a rigid rod being pushed by a constant force, a rigid string whose endpoints are simultaneously set in motion (seen as a special case of Bell's spaceships paradox), and a radial rigid string that has partially crossed the event horizon of a Schwarzschild black hole while still being held from the outside.
Low Tension Strings on a Cosmological Singularity
Ben Craps; Chethan Krishnan; Ayush Saurabh
2014-09-21T23:59:59.000Z
It has recently been argued that the singularity of the Milne orbifold can be resolved in higher spin theories. In string theory scattering amplitudes, however, the Milne singularity gives rise to ultraviolet divergences that signal uncontrolled backreaction. Since string theory in the low tension limit is expected to be a higher spin theory (although precise proposals only exist in special cases), we investigate what happens to these scattering amplitudes in the low tension limit. We point out that the known problematic ultraviolet divergences disappear in this limit. In addition we systematically identify all divergences of the simplest 2-to-2 string scattering amplitude on the Milne orbifold, and argue that the divergences that survive in the low tension limit have sensible infrared interpretations.
Closed string field theory in a-gauge
Masako Asano; Mitsuhiro Kato
2012-09-09T23:59:59.000Z
We show that a-gauge, a class of covariant gauges developed for bosonic open string field theory, is consistently applied to the closed string field theory. A covariantly gauge-fixed action of massless fields can be systematically derived from a-gauge-fixed action of string field theory.
Perturbative diagrams in string field theory
Washington Taylor
2002-07-13T23:59:59.000Z
A general algorithm is presented which gives a closed-form expression for an arbitrary perturbative diagram of cubic string field theory at any loop order. For any diagram, the resulting expression is given by an integral of a function of several infinite matrices, each built from a finite number of blocks containing the Neumann coefficients of Witten's 3-string vertex. The closed-form expression for any diagram can be approximated by level truncation on oscillator level, giving a computation involving finite size matrices. Some simple tree and loop diagrams are worked out as examples of this approach.
Perturbative computations in string field theory
Washington Taylor
2004-04-15T23:59:59.000Z
These notes describe how perturbative on-shell and off-shell string amplitudes can be computed using string field theory. Computational methods for approximating arbitrary amplitudes are discussed, and compared with standard world-sheet methods for computing on-shell amplitudes. These lecture notes are not self-contained; they contain the material from W. Taylor's TASI 2003 lectures not covered in the recently published ``TASI 2001'' notes {\\tt hep-th/0311017} by Taylor and Zwiebach, and should be read as a supplement to those notes.
Parallel ion strings in linear multipole traps
Mathieu Marciante; Caroline Champenois; J. Pedregosa-Gutierrez; Annette Calisti; Martina Knoop
2011-03-13T23:59:59.000Z
Additional radio-frequency (rf) potentials applied to linear multipole traps create extra field nodes in the radial plane which allow one to confine single ions, or strings of ions, in totally rf field-free regions. The number of nodes depends on the order of the applied multipole potentials and their relative distance can be easily tuned by the amplitude variation of the applied voltages. Simulations using molecular dynamics show that strings of ions can be laser cooled down to the Doppler limit in all directions of space. Once cooled, organized systems can be moved with very limited heating, even if the cooling process is turned off.
Cosmic strings: A problem or a solution
Bennett, D.P.; Bouchet, F.R.
1987-10-01T23:59:59.000Z
The most fundamental issue in the theory of cosmic strings is addressed by means of Numerical Simulations: the existence of a scaling solution. The resolution of this question will determine whether cosmic strings can form the basis of an attractive theory of galaxy formation or prove to be a cosmological disaster like magnetic monopoles or domain walls. After a brief discussion of our numerical technique, results are presented which, though still preliminary, offer the best support to date of this scaling hypothesis. 6 refs., 2 figs.
Closed strings from decaying D-branes
Neil Lambert; Hong Liu; Juan Maldacena
2007-02-05T23:59:59.000Z
We compute the emission of closed string radiation from homogeneous rolling tachyons. For an unstable decaying D$p$-brane the radiated energy is infinite to leading order for $p\\leq 2$ and finite for $p>2$. The closed string state produced by a decaying brane is closely related to the state produced by D-instantons at a critical Euclidean distance from $t=0$. In the case of a D0 brane one can cutoff this divergence so that we get a finite energy final state which would be the state that the brane decays into.
Non-Abelian String-Net Ladders
M. D. Schulz; S. Dusuel; J. Vidal
2014-10-15T23:59:59.000Z
We study the string-net model with a string tension for non-Abelian particles in the ladder geometry. Focusing on the simplest non-Abelian theory with a total quantum dimension larger than two, we find evidence for a "russian doll" spectrum featuring size-independent energy levels. Contrary to Fibonacci and Ising ladders, the spectrum is found to be gapped at the self-dual points and low-energy excitations in the ground-state sector consist in two-quasiparticle bound states that are discussed in the weak-tension limit. We argue that such properties are prototypical of theories containing more than one non-Abelian particle.
Paris-Sud XI, Université de
Semi-analytical model of brine and CO2 leakage through an abandoned plugged well. Applications for determining an Area of Review and CO2 leakage rate Arnaud Réveillère, Jérémy Rohmer, Frédéric Wertz / contact the leak, and of CO2,g as a first approach. Compared to the state of the art, it adds the possibility
Girguis, Peter R.
, likely exceeding reserves of conventional oil and gas (Collett and Kuuskraa, 1998). In deep-ocean regionsNew constraints on methane fluxes and rates of anaerobic methane oxidation in a Gulf of Mexico Keywords: Methane flux Mass spectrometer Brine pool Methane oxidation Gulf of Mexico a b s t r a c t Deep
94 LITHIUM (Data in metric tons of lithium content unless otherwise noted) Domestic Production and Use: The only commercially active lithium mine in the United States was a brine operation in Nevada. The mine's production capacity was expanded in 2012, and a new lithium hydroxide plant opened in North
Abelian-Higgs strings in Rastall gravity
Eugenio R. Bezerra de Mello; Julio C. Fabris; Betti Hartmann
2015-04-02T23:59:59.000Z
In this paper we analyze Abelian-Higgs strings in a phenomenological model that takes quantum effects in curved space-time into account. This model, first introduced by Rastall, cannot be derived from an action principle. We formulate phenomenological equations of motion under the guiding principle of minimal possible deformation of the standard equations. We construct string solutions that asymptote to a flat space-time with a deficit angle by solving the set of coupled non-linear ordinary differential equations numerically. Decreasing the Rastall parameter from its Einstein gravity value we find that the deficit angle of the space-time increases and becomes equal to $2\\pi$ at some critical value of this parameter that depends on the remaining couplings in the model. For smaller values the resulting solutions are supermassive string solutions possessing a singularity at a finite distance from the string core. Assuming the Higgs boson mass to be on the order of the gauge boson mass we find that also in Rastall gravity this happens only when the symmetry breaking scale is on the order of the Planck mass. We also observe that for specific values of the parameters in the model the energy per unit length becomes proportional to the winding number, i.e. the degree of the map $S^1 \\rightarrow S^1$. Unlike in the BPS limit in Einstein gravity, this is, however, not connect to an underlying mathematical structure, but rather constitutes a would-be-BPS bound.
D-branes and string field theory
Sigalov, Ilya
2006-01-01T23:59:59.000Z
In this thesis we study the D-brane physics in the context of Witten's cubic string field theory. We compute first few terms the low energy effective action for the non-abelian gauge field A, from Witten's action. We show ...
Thin Shell Wormhole in Heterotic String Theory
F. Rahaman; M. Kalam; S. Chakraborti
2006-11-25T23:59:59.000Z
Using 'Cut and Paste' technique, we develop a thin shell wormhole in heterotic string theory. We determine the surface stresses, which are localized in the shell, by using Darmois-Israel formalism. The linearized stability of this thin wormhole is also analyzed.
String inspired effective Lagrangian and Inflationary Universe
E. Abdalla; A. C. V. V. de Siqueira
1993-01-26T23:59:59.000Z
We consider a string inspired effective Lagrangian for the graviton and dilaton, containing Einstein gravity at the zero slope limit. The numerical solution of the problem shows asymptotically an inflationary universe. The time is measured by the dilaton, as one expects. The result is independent of the introduction of ad-hoc self interactions for the dilaton field.
P. S. Howe; N. D. Lambert; P. C. West
1997-09-09T23:59:59.000Z
We obtain a BPS soliton of the M theory fivebrane's equations of motion representing a supersymmetric self-dual string. The resulting solution is then dimensionally reduced and used to obtain 0-brane and (p-2)-brane solitons on D-p-branes.
Ali, Mir; Ruiz, Frenny; Saint-Victor, Carlos [Physics Department, New York City College of Technology, City University of New York 300 Jay Street, Brooklyn, New York 11201 (United States); Vazquez-Poritz, Justin F. [Physics Department, New York City College of Technology, City University of New York 300 Jay Street, Brooklyn, New York 11201 (United States); Graduate School and University Center, City University of New York 365 Fifth Avenue, New York, New York 10016 (United States)
2009-08-15T23:59:59.000Z
We consider the behavior of open strings on anti-de Sitter wormholes in Gauss-Bonnet theory, which are the Gauss-Bonnet gravity duals of a pair of field theories. A string with both endpoints on the same side of the wormhole describes two charges within the same field theory, which exhibit Coulomb interaction for small separation. On the other hand, a string extending through the wormhole describes two charges which live in different field theories, and they exhibit a springlike confining potential. A transition occurs when there is a pair of charges present within each field theory: for small separation each pair of charges exhibits Coulomb interaction, while for large separation the charges in the different field theories pair up and exhibit confinement. Two steadily-moving charges in different field theories can occupy the same location provided that their speed is less than a critical speed, which also plays the role of a subluminal speed limit. However, for some wormhole backgrounds, charges moving at the critical speed cannot occupy the same location and energy is transferred from the leading charge to the lagging one. We also show that strings on anti-de Sitter wormholes in supergravity theories without higher-derivative curvature terms can exhibit these properties as well.
Towards Dark Energy from String-Theory
Axel Krause
2008-03-12T23:59:59.000Z
We discuss vacuum energy in string and M-theory with a focus on heterotic M-theory. In the latter theory a mechanism is described for maintaining zero vacuum energy after supersymmetry breaking. Higher-order corrections can be expected to give a sufficiently small amount of vacuum energy to possibly account for dark energy.
Kink in superconducting cosmic string: exact solution
Ernst Trojan
2014-12-24T23:59:59.000Z
We solve the equations of motion and find the Lorentz transformation associated with a kink in superconducting cosmic string. The kink velocity does not depend on its amplitude. The kink amplitude cannot be arbitrary but it varies within definite range and determines the explicit form of the relevant Lorentz transformation.
Kharaka, Y.K; Doughty, C.; Freifeld, B.M.; Daley, T.M.; Xu, T.
2009-11-01T23:59:59.000Z
To demonstrate the potential for geologic storage of CO{sub 2} in saline aquifers, the Frio-I Brine Pilot was conducted, during which 1600 tons of CO{sub 2} were injected into a high-permeability sandstone and the resulting subsurface plume of CO{sub 2} was monitored using a variety of hydrogeological, geophysical, and geochemical techniques. Fluid samples were obtained before CO{sub 2} injection for baseline geochemical characterization, during the CO{sub 2} injection to track its breakthrough at a nearby observation well, and after injection to investigate changes in fluid composition and potential leakage into an overlying zone. Following CO{sub 2} breakthrough at the observation well, brine samples showed sharp drops in pH, pronounced increases in HCO{sub 3}{sup -} and aqueous Fe, and significant shifts in the isotopic compositions of H{sub 2}O and dissolved inorganic carbon. Based on a calibrated 1-D radial flow model, reactive transport modeling was performed for the Frio-I Brine Pilot. A simple kinetic model of Fe release from the solid to aqueous phase was developed, which can reproduce the observed increases in aqueous Fe concentration. Brine samples collected after half a year had lower Fe concentrations due to carbonate precipitation, and this trend can be also captured by our modeling. The paper provides a method for estimating potential mobile Fe inventory, and its bounding concentration in the storage formation from limited observation data. Long-term simulations show that the CO{sub 2} plume gradually spreads outward due to capillary forces, and the gas saturation gradually decreases due to its dissolution and precipitation of carbonates. The gas phase is predicted to disappear after 500 years. Elevated aqueous CO{sub 2} concentrations remain for a longer time, but eventually decrease due to carbonate precipitation. For the Frio-I Brine Pilot, all injected CO{sub 2} could ultimately be sequestered as carbonate minerals.
Strings, vortex rings, and modes of instability
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gubser, Steven S.; Nayar, Revant; Parikh, Sarthak
2015-03-01T23:59:59.000Z
We treat string propagation and interaction in the presence of a background Neveu–Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scalemore »which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross–Pitaevskii Lagrangian, and also how it compares to the action for giant gravitons.« less
Open string amplitudes of closed topological vertex
Kanehisa Takasaki; Toshio Nakatsu
2015-07-25T23:59:59.000Z
The closed topological vertex is the simplest "off-strip" case of non-compact toric Calabi-Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an "on-strip" subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive $q$-difference equations for generating functions of special subsets of the amplitudes. These $q$-difference equations may be interpreted as the defining equation of a quantum mirror curve.
Vacuum selection on the string landscape
Tetteh-Lartey, Edward [Department of Physics, Texas A and M University, College Station, Texas 77845 (United States)
2007-05-15T23:59:59.000Z
I examine some nonanthropic approaches to the string landscape. These approaches are based on finding the initial conditions of the universe using the wave function of the multiverse to select the most probable vacuum out of this landscape. All approaches tackled so far seem to have their own problems and there is no clear-cut alternative to anthropic reasoning. I suggest that finding the initial conditions may be irrelevant since all possible vacua on the landscape are possible initial state conditions and eternal inflation could generate all the other vacua. We are now left to reason out why we are observing the small value of the cosmological constant. I address this issue in the context of noncritical string theory in which all values of the cosmological constant on the landscape are departures from the critical equilibrium state.
Signal connection for a downhole tool string
Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Bradford, Kline; Fox, Joe; Briscoe, Michael
2006-08-29T23:59:59.000Z
A signal transmission connection for a tool string used in exploration and production of natural resources, namely: oil, gas, and geothermal energy resources. The connection comprises first and second annular elements deployed in cooperative association with each other. The respective elements comprise inductive transducers that are capable of two-way signal transmission between each other, with downhole components of the tool string, and with ground-level equipment. The respective inductive transducers comprise one or more conductive loops housed within ferrite troughs, or within ferrite trough segments. When energized, the conductive loops produce a magnetic field suitable for transmitting the signal. The second element may be rotational in drilling applications. The respective elements may be fitted with electronic equipment to aid and manipulate the transmission of the signal. The first element may also be in communication with the World Wide Web.
Jung, Hun Bok; Um, Wooyong; Cantrell, Kirk J.
2013-09-16T23:59:59.000Z
Co-injection of oxygen, a significant component in CO2 streams produced by the oxyfuel combustion process, can cause a significant alteration of the redox state in deep geologic formations during geologic carbon sequestration. The potential impact of co-injected oxygen on the interaction between synthetic CO2-brine (0.1 M NaCl) and shale caprock (Gothic shale from the Aneth Unit in Utah) and mobilization of trace metals was investigated at ~10 MPa and ~75 °C. A range of relative volume percentages of O2 to CO2 (0, 1, 4 and 8%) were used in these experiments to address the effect of oxygen on shale-CO2-brine interaction under various conditions. Major mineral phases in Gothic shale are quartz, calcite, dolomite, montmorillonite, and pyrite. During Gothic shale-CO2-brine interaction in the presence of oxygen, pyrite oxidation occurred extensively and caused enhanced dissolution of calcite and dolomite. Pyrite oxidation and calcite dissolution subsequently resulted in the precipitation of Fe(III) oxides and gypsum (CaSO4•2H2O). In the presence of oxygen, dissolved Mn and Ni were elevated because of oxidative dissolution of pyrite. The mobility of dissolved Ba was controlled by barite (BaSO4) precipitation in the presence of oxygen. Dissolved U in the experimental brines increased to ~8–14 ?g/L, with concentrations being slightly higher in the absence of oxygen than in the presence of oxygen. Experimental and modeling results indicate the interaction between shale caprock and oxygen co-injected with CO2 during geologic carbon sequestration can exert significant impacts on brine pH, solubility of carbonate minerals, stability of sulfide minerals, and mobility of trace metals. The major impact of oxygen is most likely to occur in the zone near CO2 injection wells where impurity gases can accumulate. Oxygen in CO2-brine migrating away from the injection well will be continually consumed through the reactions with sulfide minerals in deep geologic formations.
Two Dimensional QCD is a String Theory
David J. Gross; Washington Taylor
1993-01-18T23:59:59.000Z
The partition function of two dimensional QCD on a Riemann surface of area $A$ is expanded as a power series in $1/N$ and $A$. It is shown that the coefficients of this expansion are precisely determined by a sum over maps from a two dimensional surface onto the two dimensional target space. Thus two dimensional QCD has a simple interpretation as a closed string theory.
Jet fragmentation and gauge/string duality
Yoshitaka Hatta; Toshihiro Matsuo
2008-05-27T23:59:59.000Z
We consider an analog of e^+e^- annihilation in gauge theories which have a dual string description in asymptotically AdS_5 space and discuss the nature of jet fragmentation. We construct the timelike anomalous dimension which governs the scale dependence of the fragmentation function. In the limit of infinite 't Hooft coupling, the average multiplicity rises linearly with the energy and the inclusive spectrum is peaked at the kinematical boundary.
Traversable wormholes in a string cloud
Martin Richarte; Claudio Simeone
2007-11-14T23:59:59.000Z
We study spherically symmetric thin-shell wormholes in a string cloud background in (3+1)-dimensional spacetime. The amount of exotic matter required for the construction, the traversability and the stability under radial perturbations, are analyzed as functions of the parameters of the model. Besides, in the Appendices a non perturbative approach to the dynamics and a possible extension of the analysis to a related model are briefly discussed.
Topological insulators and superconductors from string theory
Ryu, Shinsei; Takayanagi, Tadashi [Department of Physics, University of California, Berkeley, California 94720 (United States); Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwa, Chiba 277-8582 (Japan)
2010-10-15T23:59:59.000Z
Topological insulators and superconductors in different spatial dimensions and with different discrete symmetries have been fully classified recently, revealing a periodic structure for the pattern of possible types of topological insulators and superconductors, both in terms of spatial dimensions and in terms of symmetry classes. It was proposed that K theory is behind the periodicity. On the other hand, D-branes, a solitonic object in string theory, are also known to be classified by K theory. In this paper, by inspecting low-energy effective field theories realized by two parallel D-branes, we establish a one-to-one correspondence between the K-theory classification of topological insulators/superconductors and D-brane charges. In addition, the string theory realization of topological insulators and superconductors comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature, such as ones with the Chern-Simons term or the {theta} term in various dimensions. This sheds light on topological insulators and superconductors beyond noninteracting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions. Increasing the number of D-branes naturally leads to a realization of topological insulators and superconductors in terms of holography (AdS/CFT).
Topological Insulators and Superconductors from String Theory
Shinsei Ryu; Tadashi Takayanagi
2010-08-01T23:59:59.000Z
Topological insulators and superconductors in different spatial dimensions and with different discrete symmetries have been fully classified recently, revealing a periodic structure for the pattern of possible types of topological insulators and supercondutors, both in terms of spatial dimensions and in terms of symmetry classes. It was proposed that K-theory is behind the periodicity. On the other hand, D-branes, a solitonic object in string theory, are also known to be classified by K-theory. In this paper, by inspecting low-energy effective field theories realized by two parallel D-branes, we establish a one-to-one correspondence between the K-theory classification of topological insulators/superconductors and D-brane charges. In addition, the string theory realization of topological insulators and superconductors comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature, such as ones with the Chern-Simons term or the $\\theta$-term in various dimensions. This sheds light on topological insulators and superconductors beyond non-interacting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions. Increasing the number of D-branes naturally leads to a realization of topological insulators and superconductors in terms of holography (AdS/CFT).
String melting in a photon bath
Karouby, Johanna, E-mail: karoubyj@mit.edu [Center for Theoretical Physics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachussetts 02139 (United States)
2013-10-01T23:59:59.000Z
We compute the decay rate of a metastable cosmic string in contact with a thermal bath by finding the instanton solution. The new feature is that this decay rate is found in the context of non thermal scalar fields in contact with a thermal bath of photons. In general, to make topologically unstable strings stable, one can couple them to such a bath. The resulting plasma effect creates metastable configurations which can decay from the false vacuum to the true vacuum. In our specific set-up, the instanton computation is realized for the case of two out-of-equilibrium complex scalar fields: one is charged and coupled to the photon field, and the other is neutral. New effects coming from the thermal bath of photons make the radius of the nucleated bubble and most of the relevant physical quantities temperature-dependent. However, the temperature appears in a different way than in the purely thermal case, where all scalar fields are in thermal equilibrium. As a result of the tunneling, the core of the initial string melts while bubbles of true vacuum expand at the speed of light.
Local cosmic string in generalised scalar tensor theory
A. A. Sen; N. Banerjee
1998-02-25T23:59:59.000Z
A recent investigation shows that a local gauge string with a phenomenological energy momentum tensor, as prescribed by Vilenkin, is inconsistent in Brans-Dicke theory. In this work it has been shown that such a string is consistent in a more general scalar tensor theory where $\\omega$ is function of the scalar field.A set of solutions of full nonlinear Einstein's equations for interior region of such a string are presented.
N. Seiberg; L. Susskind; N. Toumbas
2000-05-04T23:59:59.000Z
Searching for space/time noncommutativity we reconsider open strings in a constant background electric field. The main difference between this situation and its magnetic counterpart is that here there is a critical electric field beyond which the theory does not make sense. We show that this critical field prevents us from finding a limit in which the theory becomes a field theory on a noncommutative spacetime. However, an appropriate limit toward the critical field leads to a novel noncritical string theory on a noncommutative spacetime.
Non-linear sigma-models and string theories
Sen, A.
1986-10-01T23:59:59.000Z
The connection between sigma-models and string theories is discussed, as well as how the sigma-models can be used as tools to prove various results in string theories. Closed bosonic string theory in the light cone gauge is very briefly introduced. Then, closed bosonic string theory in the presence of massless background fields is discussed. The light cone gauge is used, and it is shown that in order to obtain a Lorentz invariant theory, the string theory in the presence of background fields must be described by a two-dimensional conformally invariant theory. The resulting constraints on the background fields are found to be the equations of motion of the string theory. The analysis is extended to the case of the heterotic string theory and the superstring theory in the presence of the massless background fields. It is then shown how to use these results to obtain nontrivial solutions to the string field equations. Another application of these results is shown, namely to prove that the effective cosmological constant after compactification vanishes as a consequence of the classical equations of motion of the string theory. 34 refs. (LEW)
String Loop Corrections to Stable Non-BPS Branes
N. D. Lambert; I. Sachs
2000-10-31T23:59:59.000Z
We calculate the string loop corrections to the tachyon potential for stable non-BPS Dp-branes on the orbifold T^4/Z_2. We find a non-trivial phase structure and we show that, after tachyon condensation, the non-BPS Dp-branes are attracted to each other for p=0,1,2. We then identify the corresponding closed string boundary states together with the massless long range fields they excite. For p=3,4 the string loop correction diverge. We identify the massless closed string fields responsible for these divergencies and regularise the partition function using a Fischler-Susskind mechanism.
Efficient solutions for the Far From Most String Problem
Daniele Ferone,,,
niques for string selection and comparison problems in genomics. IEEE. Engineering in Medicine and Biology Magazine, 24(3):81–87, 2005. [29] C.A.S. Oliveira ...
Exact entanglement renormalization for string-net models
Robert Koenig; Ben W. Reichardt; Guifre Vidal
2009-06-15T23:59:59.000Z
We construct an explicit renormalization group (RG) transformation for Levin and Wen's string-net models on a hexagonal lattice. The transformation leaves invariant the ground-state "fixed-point" wave function of the string-net condensed phase. Our construction also produces an exact representation of the wave function in terms of the multi-scale entanglement renormalization ansatz (MERA). This sets the stage for efficient numerical simulations of string-net models using MERA algorithms. It also provides an explicit quantum circuit to prepare the string-net ground-state wave function using a quantum computer.
The Hubble Web: The Dark Matter Problem and Cosmic Strings
Stephon Alexander
2007-02-27T23:59:59.000Z
I propose a reinterpretation of cosmic dark matter in which a rigid network of cosmic strings formed at the end of inflation. The cosmic strings fulfill three functions: At recombination they provide an accretion mechanism for virializing baryonic and warm dark matter into disks. These cosmic strings survive as configurations which thread spiral and elliptical galaxies leading to the observed flatness of rotation curves and the Tully-Fisher relation. We find a relationship between the rotational velocity of the galaxy and the string tension and discuss the testability of this model.
Freeze, G.A. [INTERA Inc., Albuquerque, NM (United States); Larson, K.W.; Davies, P.B.; Webb, S.W. [Sandia National Labs., Albuquerque, NM (United States)
1995-10-01T23:59:59.000Z
Long-term repository assessment must consider the processes of (1) gas generation, (2) room closure and expansions due to salt creep, and (3) multiphase (brine and gas) fluid flow, as well as the complex coupling between these three processes. The mechanical creep closure code SANCHO was used to simulate the closure of a single, perfectly sealed disposal room filled with water and backfill. SANCHO uses constitutive models to describe salt creep, waste consolidation, and backfill consolidation, Five different gas-generation rate histories were simulated, differentiated by a rate multiplier, f, which ranged from 0.0 (no gas generation) to 1.0 (expected gas generation under brine-dominated conditions). The results of the SANCHO f-series simulations provide a relationship between gas generation, room closure, and room pressure for a perfectly sealed room. Several methods for coupling this relationship with multiphase fluid flow into and out of a room were examined. Two of the methods are described.
Shao, Hongbo; Thompson, Christopher J.; Cantrell, Kirk J.
2013-11-01T23:59:59.000Z
pH is an essential parameter for understanding the geochemical reactions that occur in rock-brine-CO2 systems when CO2 is injected into deep geologic formations for long-term storage. Due to a lack of reliable experimental methods, most laboratory studies conducted under geological CO2 sequestration (GCS) conditions have relied on thermodynamic modeling to estimate pH. The accuracy of these model predictions is typically uncertain. In our previous work, we have developed a method for pH determination by in-situ spectrophotometry. In the present work, we expanded the applicable pH range for this method and measured the pH of several rock-brine-CO2 systems at GCS conditions for five rock samples collected from ongoing GCS demonstration projects. Experimental measurements were compared with pH values calculated using several geochemical modeling approaches. The effect of different thermodynamic databases on the accuracy of model prediction was evaluated. Results indicate that the accuracy of model calculations is rock-dependent. For rocks comprised of carbonate and sandstone, model results generally agreed well with experimentally measured pH; however, for basalt, significant differences were observed. These discrepancies may be due to the models’ failure to fully account for certain reaction occurring between the basalt minerals the CO2-saturated brine solutions.
CMB ISW-lensing bispectrum from cosmic strings
Daisuke Yamauchi; Yuuiti Sendouda; Keitaro Takahashi
2014-10-21T23:59:59.000Z
We study the effect of weak lensing by cosmic (super-)strings on the higher-order statistics of the cosmic microwave background (CMB). A cosmic string segment is expected to cause weak lensing as well as an integrated Sachs-Wolfe (ISW) effect, the so-called Gott-Kaiser-Stebbins (GKS) effect, to the CMB temperature fluctuation, which are thus naturally cross-correlated. We point out that, in the presence of such a correlation, yet another kind of the post-recombination CMB temperature bispectra, the ISW-lensing bispectra, will arise in the form of products of the auto- and cross-power spectra. We first present an analytic method to calculate the autocorrelation of the temperature fluctuations induced by the strings, and the cross-correlation between the temperature fluctuation and the lensing potential both due to the string network. In our formulation, the evolution of the string network is assumed to be characterized by the simple analytic model, the velocity-dependent one scale model, and the intercommutation probability is properly incorporated in orderto characterize the possible superstringy nature. Furthermore, the obtained power spectra are dominated by the Poisson-distributed string segments, whose correlations are assumed to satisfy the simple relations. We then estimate the signal-to-noise ratios of the string-induced ISW-lensing bispectra and discuss the detectability of such CMB signals from the cosmic string network. It is found that in the case of the smaller string tension, $G\\mu\\ll 10^{-7}$\\,, the ISW-lensing bispectrum induced by a cosmic string network can constrain the string-model parameters even more tightly than the purely GKS-induced bispectrum in the ongoing and future CMB observations on small scales.
Daley, T.M.; Ajo-Franklin, J.; Doughty, C.A.
2011-02-15T23:59:59.000Z
Crosswell CASSM (continuous active-source seismic monitoring) data was acquired as part of the Frio-II brine pilot CO{sub 2} injection experiment. To gain insight into the CO{sub 2} plume evolution, we have integrated the 3D multiphase flow modeling code TOUGH2 with seismic simulation codes via a petrophysical model that predicts seismic velocity for a given CO{sub 2} saturation. Results of forward seismic modeling based on the CO{sub 2} saturation distribution produced by an initial TOUGH2 model compare poorly with the CASSM data, indicating that the initial flow model did not capture the actual CO{sub 2} plume dynamics. Updates to the TOUGH2 model required to better match the CASSM field data indicate vertical flow near the injection well, with increased horizontal plume growth occurring at the top of the reservoir sand. The CASSM continuous delay time data are ideal for constraining the modeled spatiotemporal evolution of the CO{sub 2} plume and allow improvement in reservoir model and estimation of CO{sub 2} plume properties.
Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.; Hedin, Robert S.; Weaver, Theodore J.; Edenborn, Harry M.
2013-04-01T23:59:59.000Z
Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.
Lattice String Breaking and Heavy Meson Decays
I T Drummond; R R Horgan
1998-11-11T23:59:59.000Z
We show how string breaking on the lattice, treated as a mixing effect, can be related to decay rates for heavy quark systems. We use this to make a preliminary calculation of the energy split at maximum mixing for static quarks in QCD from the decay rate for $\\Upsilon(4S)\\to B{\\bar B}$. We extend the calculation to achieve rough estimates for the contributions of channels involving $B, B^*, B_s and B_s^*$ mesons to the width of the $\\Upsilon(5S)$.
Quantum string cosmology in the phase space
Ruben Cordero; Erik Diaz; Hugo Garcia-Compean; Francisco J. Turrubiates
2011-09-22T23:59:59.000Z
Deformation quantization is applied to quantize gravitational systems coupled with matter. This quantization procedure is performed explicitly for quantum cosmology of these systems in a flat minisuper(phase)space. The procedure is employed in a quantum string minisuperspace corresponding to an axion-dilaton system in an isotropic FRW Universe. The Wheeler-DeWitt-Moyal equation is obtained and its corresponding Wigner function is given analytically in terms of Meijer's functions. Finally, this Wigner functions is used to extract physical information of the system.
The viscosity bound in string theory
Aninda Sinha; Robert C. Myers
2009-09-11T23:59:59.000Z
The ratio of shear viscosity to entropy density $\\eta/s$ of any material in nature has been conjectured to have a lower bound of $1/4\\pi$, the famous KSS bound. We examine string theory models for evidence in favour of and against this conjecture. We show that in a broad class of models quantum corrections yield values of $\\eta/s$ just above the KSS bound. However, incorporating matter fields in the fundamental representation typically leads to violations of this bound. We also outline a program to extend AdS/CFT methods to RHIC phenomenology.
The M Theory Five-Brane and the Heterotic String
John H. Schwarz
1997-05-13T23:59:59.000Z
Brane actions with chiral bosons present special challenges. Recent progress in the description of the two main examples -- the M theory five-brane and the heterotic string -- is described. Also, double dimensional reduction of the M theory five-brane on K3 is shown to give the heterotic string.
Gravitational Radiation from Travelling Waves on D-Strings
Julie D. Blum
2003-08-21T23:59:59.000Z
Boundary states that preserve supersymmetry are constructed for fractional D-strings with travelling waves on a ${\\bf C}^3/ {{\\bf Z}_2\\times {\\bf Z}_2}$ orbifold. The gravitational radiation emitted between two D-strings with antiparallel travelling waves is calculated.
Resonant acoustic transducer system for a well drilling string
Nardi, Anthony P. (Burlington, MA)
1981-01-01T23:59:59.000Z
For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.
Resonant acoustic transducer system for a well drilling string
Kent, William H. (Westford, MA); Mitchell, Peter G. (Concord, MA)
1981-01-01T23:59:59.000Z
For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.
Quantum Fusion of Strings (Flux Tubes) and Domain Walls
S. Bolognesi; M. Shifman; M. B. Voloshin
2009-05-20T23:59:59.000Z
We consider formation of composite strings and domain walls as a result of fusion of two elementary objects (elementary strings in the first case and elementary walls in the second) located at a distance from each other. The tension of the composite object T_2 is assumed to be less than twice the tension of the elementary object T_1, so that bound states are possible. If in the initial state the distance d between the fusing strings or walls is much larger than their thickness and satisfies the conditions T_1 d^2 >> 1 (in the string case) and T_1 d^3 >> 1 (in the wall case), the problem can be fully solved quasiclassically. The fusion probability is determined by the first, "under the barrier" stage of the process. We find the bounce configuration and its extremal action S_B. In the wall problem e^{-S_B} gives the fusion probability per unit time per unit area. In the string case, due to a logarithmic infrared divergence, the problem is well formulated only for finite-length strings. The fusion probability per unit time can be found in the limit in which the string length is much larger than the distance between two merging strings.
Light $U(1)$s in heterotic string models
Mehta, Viraf M
2015-01-01T23:59:59.000Z
We present a novel string-derived $U(1)$ combination that satisfies necessary properties to survive to low scales. We discuss previous attempts at acquiring such an abelian gauge symmetry from two different string embeddings and the pitfalls associated with them. Finally, we give an example of how a satisfactory model may be constructed within our framework.
Dynamics of a self-gravitating thin cosmic string
B. Boisseau; C. Charmousis; B. Linet
1997-02-06T23:59:59.000Z
We assume that a self-gravitating thin string can be locally described by what we shall call a smoothed cone. If we impose a specific constraint on the model of the string, then its central line obeys the Nambu-Goto equations. If no constraint is added, then the worldsheet of the central line is a totally geodesic surface.
Quantum computational tensor network on string-net condensate
Tomoyuki Morimae
2011-09-27T23:59:59.000Z
The string-net condensate is a new class of materials which exhibits the quantum topological order. In order to answer the important question, "how useful is the string-net condensate in quantum information processing?", we consider the most basic example of the string-net condensate, namely the $Z_2$ gauge string-net condensate on the two-dimensional hexagonal lattice, and show that the universal measurement-based quantum computation (in the sense of the quantum computational webs) is possible on it by using the framework of the quantum computational tensor network. This result implies that even the most basic example of the string-net condensate is equipped with the correlation space that has the capacity for the universal quantum computation.
Axion inflation in type II string theory
Grimm, Thomas W. [Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany) and Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)
2008-06-15T23:59:59.000Z
Inflationary models driven by a large number of axion fields are discussed in the context of type IIB compactifications with N=1 supersymmetry. The inflatons arise as the scalar modes of the R-R two-forms evaluated on vanishing two-cycles in the compact geometry. The vanishing cycles are resolved by small two-volumes or NS-NS B fields which sit together with the inflatons in the same supermultiplets. String world sheets wrapping the vanishing cycles correct the metric of the R-R inflatons. They can help to generate kinetic terms close to the Planck scale and a mass hierarchy between the axions and their nonaxionic partners during inflation. At small string coupling, D-brane corrections are subleading in the metric of the R-R inflatons. However, an axion potential can be generated by D1 instantons or gaugino condensates on D5-branes. Models with a sufficiently large number of axions admit regions of chaotic inflation which can stretch over the whole axion field range for potentials from gaugino condensates. These models could allow for a possibly detectable amount of gravitational waves with tensor to scalar ratio as high as r<0.14.
Strings, black holes, and quantum information
Kallosh, Renata; Linde, Andrei [Department of Physics, Stanford University, Stanford, California 94305 (United States)
2006-05-15T23:59:59.000Z
We find multiple relations between extremal black holes in string theory and 2- and 3-qubit systems in quantum information theory. We show that the entropy of the axion-dilaton extremal black hole is related to the concurrence of a 2-qubit state, whereas the entropy of the STU black holes, Bogomol'nyi-Prasad-Sommerfield (BPS) as well as non-BPS, is related to the 3-tangle of a 3-qubit state. We relate the 3-qubit states with the string theory states with some number of D-branes. We identify a set of large black holes with the maximally entangled Greenberger, Horne, Zeilinger (GHZ) class of states and small black holes with separable, bipartite, and W states. We sort out the relation between 3-qubit states, twistors, octonions, and black holes. We give a simple expression for the entropy and the area of stretched horizon of small black holes in terms of a norm and 2-tangles of a 3-qubit system. Finally, we show that the most general expression for the black hole and black ring entropy in N=8 supergravity/M theory, which is given by the famous quartic Cartan E{sub 7(7)} invariant, can be reduced to Cayley's hyperdeterminant describing the 3-tangle of a 3-qubit state.
FRACTAL STRINGS AND MULTIFRACTAL ZETA MICHEL L. LAPIDUS, JACQUES LEVY-VEHEL
Paris-Sud XI, UniversitÃ© de
FRACTAL STRINGS AND MULTIFRACTAL ZETA FUNCTIONS MICHEL L. LAPIDUS, JACQUES LÂ´EVY-VÂ´EHEL AND JOHN A and the geometric zeta functions of fractal strings. The parameter value recovers the geometric zeta function func- tion of a fractal string, providing information on the structure of a given string in addition
Random fractal strings: their zeta functions, complex dimensions and spectral asymptotics
Jordan, Jonathan
Random fractal strings: their zeta functions, complex dimensions and spectral asymptotics B-increasing real numbers which sums to one. For our purposes a fractal string is a string formed from the lengths versions of fractal strings. We show that using a random re- cursive self-similar construction
The Langlands Program and String Modular K3 Surfaces
Rolf Schimmrigk
2006-03-29T23:59:59.000Z
A number theoretic approach to string compactification is developed for Calabi-Yau hypersurfaces in arbitrary dimensions. The motivic strategy involved is illustrated by showing that the Hecke eigenforms derived from Galois group orbits of the holomorphic two-form of a particular type of K3 surfaces can be expressed in terms of modular forms constructed from the worldsheet theory. The process of deriving string physics from spacetime geometry can be reversed, allowing the construction of K3 surface geometry from the string characters of the partition function. A general argument for K3 modularity follows from mirror symmetry, in combination with the proof of the Shimura-Taniyama conjecture.
AdS String: Classical Solutions and Moduli Dynamics
Antal Jevicki; Kewang Jin
2010-01-29T23:59:59.000Z
We review some recent work and techniques for constructing dynamical string solutions in AdS spacetime. These solutions generalize the folded string and multi-spike solutions of GKP and Kruczenski. The methods developed for constructing these dynamical solutions are based on Pohlmeyer reduction to integrable sinh-Gordon type equations. The integrability of the equations is seen as the crucial tool for reconstruction of the string configurations. We discuss the physical meaning of these dynamical spike solutions and the question of their moduli space.
Self-Dual Supergravity from N = 2 Strings
de Boer, J.; Skenderis, K.
1997-09-24T23:59:59.000Z
A new heterotic N = 2 string with manifest target space supersymmetry is constructed by combining a conventional N = 2 string in the right-moving sector and a Green-Schwarz-Berkovits type string in the left-moving sector. The corresponding sigma model is then obtained by turning on background fields for the massless excitations. We compute the beta functions and we partially check the OPE's of the superconformal algebra perturbatively in {alpha}{prime}, all in superspace. The resulting field equations describe N = 1 self-dual supergravity.
A note on string size evolution in phantom cosmology
Soon-Tae Hong
2015-04-05T23:59:59.000Z
We analyze evolution of string size in higher-dimensional cosmology with phantom field. Assuming that the Universe possesses the phantom field defined in a ten-dimensional spacetime, we predict string size which is claimed to be that of photon in nature at present. The Universe size increases as in the standard inflationary Universe model while the photon size decreases drastically at the early stage of the string evolution after the Big Bang. Moreover, the photon spin in the phantom Universe is analyzed in the framework of the stringy cosmology.
Fitting the Galaxy Rotation Curves: Strings versus NFW profile
Yeuk-Kwan E. Cheung; Feng Xu
2008-10-14T23:59:59.000Z
Remarkable fit of galaxy rotation curves is achieved using a simple model from string theory. The rotation curves of the same group of galaxies are also fit using dark matter model with the generalized Navarro-Frenk-White profile for comparison. String model utilizes three free parameters vs five in the dark matter model. The average chi-squared of the string model fit is 1.649 while that of the dark matter model is 1.513. The generalized NFW profile fits marginally better at a price of two more free parameters.
Cosmic string formation and the power spectrum of field configurations
James Robinson; Andrew Yates
1996-06-12T23:59:59.000Z
We examine the statistical properties of defects formed by the breaking of a U(1) symmetry when the Higgs field has a power spectrum $P(k) \\propto k^n$. We find a marked dependence of the amount of infinite string on the spectral index $n$ and empirically identify an analytic form for this quantity. We also confirm that this result is robust to changes in the definition of infinite string. It is possible that this result could account for the apparent absence of infinite string in recent lattice-free simulations.
First Structure Formation: II. Cosmic String + Hot Dark Matter Models
Tom Abel; Albert Stebbins; Peter Anninos; Michael L. Norman
1997-06-26T23:59:59.000Z
We examine the structure of baryonic wakes in the cosmological fluid which would form behind GUT-scale cosmic strings at early times (redshifts z > 100) in a neutrino-dominated universe. We show, using simple analytical arguments as well as 1- and 2-dimensional hydrodynamical simulations, that these wakes will NOT be able to form interesting cosmological objects before the neutrino component collapses. The width of the baryonic wakes (< 10 kpc comoving) is smaller than the scale of wiggles on the strings and are probably not enhanced by the wiggliness of the string network.
Dynamics of a global string with large Higgs boson mass
C. Charmousis; B. Boisseau; B. Linet
1998-01-12T23:59:59.000Z
We consider a self-gravitating string generated by a global vortex solution in general relativity. We investigate the Einstein and field equations of a global vortex in the region of its central line and at a distance from the centre of the order of the inverse of its Higgs boson mass. By combining the two we establish by a limiting process of large Higgs mass the dynamics of a self-gravitating global string. Under our assumptions the presence of gravitation restricts the world sheet of the global string to be totally geodesic.
Harmonic coordinates in the string and membrane equations
Chun-Lei He; Shou-Jun Huang
2010-04-16T23:59:59.000Z
In this note, we first show that the solutions to Cauchy problems for two versions of relativistic string and membrane equations are diffeomorphic. Then we investigate the coordinates transformation presented in Ref. [9] (see (2.20) in Ref. [9]) which plays an important role in the study on the dynamics of the motion of string in Minkowski space. This kind of transformed coordinates are harmonic coordinates, and the nonlinear relativistic string equations can be straightforwardly simplified into linear wave equations under this transformation.
Accretion onto a black hole in a string cloud background
Apratim Ganguly; Sushant G. Ghosh; Sunil D. Maharaj
2014-09-28T23:59:59.000Z
We examine the accretion process onto the black hole with a string cloud background, where the horizon of the black hole has an enlarged radius $r_H=2 M/(1-\\alpha)$, due to the string cloud parameter $\\alpha\\; (0 \\leq \\alpha cloud parameter $\\alpha$. We also find the gas compression ratios and temperature profiles below the accretion radius and at the event horizon. It is shown that the mass accretion rate, for both the relativistic and the non-relativistic fluid by a black hole in the string cloud model, increases with increase in $\\alpha$.
Dark Energy Generated by Warped Cosmic Strings
Reinoud Jan Slagter
2014-07-29T23:59:59.000Z
If we live on the weak brane in a warped 5D bulk spacetime, gravitational waves and brane fluctuations can be generated by a part of the 5D Weyl tensor and carries information of the gravitational field outside the brane. We consider the U(1) self-gravitating scalar-gauge field on the warped spacetime without bulk matter. It turns out that "branons" can be formed dynamically, due to the modified energy-momentum tensor components of the cosmic string. It turns out that the parameter $\\alpha$, i.e., the gauge-to-scalar mass, changes from a value $>1$ to a value $wave energy. It is the time-dependent part of the warp factor which triggers this extraordinary behavior.
Conformable apparatus in a drill string
Hall, David R. (Provo, UT); Hall, Jr., H. Tracy (Provo, UT); Pixton, David S. (Lehi, UT); Fox, Joe (Spanish Fork, UT)
2007-08-28T23:59:59.000Z
An apparatus in a drill string comprises an internally upset drill pipe. The drill pipe comprises a first end, a second end, and an elongate tube intermediate the first and second ends. The elongate tube and the ends comprising a continuous an inside surface with a plurality of diameters. A conformable metal tube is disposed within the drill pipe intermediate the ends thereof and terminating adjacent to the ends of the drill pipe. The conformable metal tube substantially conforms to the continuous inside surface of the metal tube. The metal tube may comprise a non-uniform section which is expanded to conform to the inside surface of the drill pipe. The non-uniform section may comprise protrusions selected from the group consisting of convolutions, corrugations, flutes, and dimples. The non-uniform section extends generally longitudinally along the length of the tube. The metal tube may be adapted to stretch as the drill pipes stretch.
Renewal Strings for Cleaning Astronomical Databases
Storkey, Amos J; Williams, Christopher K I; Mann, Robert G
2014-01-01T23:59:59.000Z
Large astronomical databases obtained from sky surveys such as the SuperCOSMOS Sky Surveys (SSS) invariably suffer from a small number of spurious records coming from artefactual effects of the telescope, satellites and junk objects in orbit around earth and physical defects on the photographic plate or CCD. Though relatively small in number these spurious records present a significant problem in many situations where they can become a large proportion of the records potentially of interest to a given astronomer. In this paper we focus on the four most common causes of unwanted records in the SSS: satellite or aeroplane tracks, scratches fibres and other linear phenomena introduced to the plate, circular halos around bright stars due to internal reflections within the telescope and diffraction spikes near to bright stars. Accurate and robust techniques are needed for locating and flagging such spurious objects. We have developed renewal strings, a probabilistic technique combining the Hough transform, renewal...
Axions as quintessence in string theory
Panda, Sudhakar [Harish-Chandra Research Institute, Allahabad 211019 (India); Sumitomo, Yoske; Trivedi, Sandip P. [Tata Institute of Fundamental Research, Mumbai 400005 (India)
2011-04-15T23:59:59.000Z
We construct a model of quintessence in string theory based on the idea of axion monodromy as discussed by McAllister, Silverstein and Westphal [L. McAllister, E. Silverstein, and A. Westphal, Phys. Rev. D 82, 046003 (2010)]. In the model, the quintessence field is an axion whose shift symmetry is broken by the presence of 5-branes which are placed in highly warped throats. This gives rise to a potential for the axion field which is slowly varying, even after incorporating the effects of moduli stabilization and supersymmetry breaking. We find that the resulting time dependence in the equation of state of dark energy is potentially detectable, depending on the initial conditions. The model has many very light extra particles which live in the highly warped throats, but these are hard to detect. A signal in the rotation of the CMB polarization can also possibly arise.
Light superconducting strings in the Galaxy
Francesc Ferrer; Tanmay Vachaspati
2006-08-08T23:59:59.000Z
Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed the presence of a strong 511 KeV gamma-ray line emission from the bulge, which require an intense source of positrons in the galactic center. These observations are hard to account for by conventional astrophysical scenarios, whereas other proposals, such as light DM, face stringent constraints from the diffuse gamma-ray background. Here we suggest that light superconducting strings could be the source of the observed 511 KeV emission. The associated particle physics, at the ~ 1 TeV scale, is within reach of planned accelerator experiments, while the distinguishing spatial distribution, proportional to the galactic magnetic field, could be mapped by SPI or by future, more sensitive, satellite missions.
Duality Symmetric String and M-Theory
David S. Berman; Daniel C. Thompson
2014-12-09T23:59:59.000Z
We review recent developments in duality symmetric string theory. We begin with the world sheet doubled formalism which describes strings in an extended space time with extra coordinates conjugate to winding modes. This formalism is T-duality symmetric and can accommodate non-geometric T-fold backgrounds which are beyond the scope of Riemannian geometry. Vanishing of the conformal anomaly of this theory can be interpreted as a set of spacetime equations for the background fields. These equations follow from an action principle that has been dubbed Double Field Theory (DFT). We review the aspects of generalised geometry relevant for DFT. We outline recent extensions of DFT and explain how, by relaxing the so-called strong constraint with a Scherk Schwarz ansatz, one can obtain backgrounds that simultaneously depend on both the regular and T-dual coordinates. This provides a purely geometric higher dimensional origin to gauged supergravities that arise from non-geometric compactification. We then turn to M-theory and describe recent progress in formulating an E_{n(n)} U-duality covariant description of the dynamics. We describe how spacetime may be extended to accommodate coordinates conjugate to brane wrapping modes and the construction of generalised metrics in this extend space that unite the bosonic fields of supergravity into a single object. We review the action principles for these theories and their novel gauge symmetries. We also describe how a Scherk Schwarz reduction can be applied in the M-theory context and the resulting relationship to the embedding tensor formulation of maximal gauged supergravities.
Kalkhoff, S.J.
1993-12-31T23:59:59.000Z
The report defines the extent of oil-field-brine contamination in ground water and streams in the Baxterville oil field area. The report is based largely on data collected during the period October 1984 through November 1985. Water samples were collected from streams and wells in the study area. Data from a previous study conducted in the vicinity of the nearby Tatum Salt Dome were used for background water-quality information. Natural surface-water quality was determined by sampling streamflow from a nearby basin having no oil field activities and from samples collected in an adjacent basin during a previous study.
Regge behavior saves String Theory from causality violations
D'Appollonio, Giuseppe; Russo, Rodolfo; Veneziano, Gabriele
2015-01-01T23:59:59.000Z
Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters $b \\le l_s$ (the string-length parameter) with $l_s \\gg R_p$ (the characteristic scale of the D$p$-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory - and in particular its Regge behavior - is taken into account.
Efficient Solutions for the Far From Most String Problem
Paola Festa
2011-04-07T23:59:59.000Z
Apr 7, 2011 ... Efficient Solutions for the Far From Most String Problem. Paola Festa(paola.festa ***at*** unina.it) Panos M. Pardalos(pardalos ***at*** ufl.edu).
TASI Lectures on Supergravity and String Vacua in Various Dimensions
Washington Taylor
2011-04-14T23:59:59.000Z
These lectures aim to provide a global picture of the spaces of consistent quantum supergravity theories and string vacua in higher dimensions. The lectures focus on theories in the even dimensions 10, 8, and 6. Supersymmetry, along with with anomaly cancellation and other quantum constraints, places strong limitations on the set of physical theories which can be consistently coupled to gravity in higher-dimensional space-times. As the dimensionality of space-time decreases, the range of possible supergravity theories and the set of known string vacuum constructions expand. These lectures develop the basic technology for describing a variety of string vacua, including heterotic, intersecting brane, and F-theory compactifications. In particular, a systematic presentation is given of the basic elements of F-theory. In each dimension, we summarize the current state of knowledge regarding the extent to which supergravity theories not realized in string theory can be shown to be inconsistent.
Regge behavior saves String Theory from causality violations
Giuseppe D'Appollonio; Paolo Di Vecchia; Rodolfo Russo; Gabriele Veneziano
2015-05-12T23:59:59.000Z
Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters $b \\le l_s$ (the string-length parameter) with $l_s \\gg R_p$ (the characteristic scale of the D$p$-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory - and in particular its Regge behavior - is taken into account.
Closed tachyon solitons in type II string theory
Iñaki García-Etxebarria; Miguel Montero; Angel M. Uranga
2015-05-20T23:59:59.000Z
Type II theories can be described as the endpoint of closed string tachyon condensation in certain orbifolds of supercritical type 0 theories. In this paper, we study solitons of this closed string tachyon and analyze the nature of the resulting defects in critical type II theories. The solitons are classified by the real K-theory groups KO of bundles associated to pairs of supercritical dimensions. For real codimension 4 and 8, corresponding to $KO({\\bf S}^4)={\\bf Z}$ and $KO({\\bf S}^8)={\\bf Z}$, the defects correspond to a gravitational instanton and a fundamental string, respectively. We apply these ideas to reinterpret the worldsheet GLSM, regarded as a supercritical theory on the ambient toric space with closed tachyon condensation onto the CY hypersurface, and use it to describe charged solitons under discrete isometries. We also suggest the possible applications of supercritical strings to the physical interpretation of the matrix factorization description of F-theory on singular spaces.
LHC Olympics Workshop and String Phenomenology 2006 Conference
David Gross
2006-10-01T23:59:59.000Z
This is the final report of the organizers of the String Phenomenolgy program of which the LHC Olympics and the String Phenomenolgy conference were a part. In addition, it includes the list of talks from our website which comprise the online proceedings. The KITP no longer publishes conferences proceedings but rather makes recordings and visuals of all talks available on its website at www.kitp.ucsb.edu Program talks are available at http://online.kitp.ucsb.edu/online/strings06/ Conference talks are are at http://online.itp.ucsb.edu/online/strings_c06/ and LHC Olympics talks are at http://online.itp.ucsb.edu/online/lhco_c06/. These talks constitute the proceedings of these meetings.
Towards a metamaterial simulation of a spinning cosmic string
Tom G. Mackay; Akhlesh Lakhtakia
2009-11-21T23:59:59.000Z
Establishing the constitutive parameters of a nonhomogeneous bianisotropic medium that is equivalent to the spacetime metric of a spinning cosmic string, in a noncovariant formalism, we found a metamaterial route to investigate the existence of closed timelike curves.
Cloud of strings for radiating black holes in Lovelock gravity
Sushant G. Ghosh; Sunil D. Maharaj
2014-09-28T23:59:59.000Z
We present exact spherically symmetric null dust solutions in the third order Lovelock gravity with a string cloud background in arbitrary $N$ dimensions,. This represents radiating black holes and generalizes the well known Vaidya solution to Lovelock gravity with a string cloud in the background. We also discuss the energy conditions and horizon structures, and explicitly bring out the effect of the string clouds on the horizon structure of black hole solutions for the higher dimensional general relativity and Einstein-Gauss-Bonnet theories. It turns out that the presence of the coupling constant of the Gauss-Bonnet terms and/or background string clouds completely changes the structure of the horizon and this may lead to a naked singularity. We recover known spherically symmetric radiating models as well as static black holes in the appropriate limits.
The Fourier-Mukai Transform in String Theory
Bjorn Andreas
2005-05-30T23:59:59.000Z
The article surveys aspects of the Fourier-Mukai transform, its relative version and some of its applications in string theory. To appear in Encyclopedia of Mathematical Physics, published by Elsevier in early 2006. Comments/corrections welcome.
Vortex scattering and intercommuting cosmic strings on a noncommutative spacetime
Joseph, Anosh; Trodden, Mark [Department of Physics, Syracuse University, Syracuse, New York 13244 (United States); Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, Pennsylvania 19104 (United States)
2010-02-15T23:59:59.000Z
We study the scattering of noncommutative vortices, based on the noncommutative field theory developed in [A. P. Balachandran, T. R. Govindarajan, G. Mangano, A. Pinzul, B. A. Qureshi, and ?>S. Vaidya, Phys. Rev. D 75, 045009 (2007).], as a way to understand the interaction of cosmic strings. In the center-of-mass frame, the effects of noncommutativity vanish, and therefore the reconnection of cosmic strings occurs in an identical manner to the commutative case. However, when scattering occurs in a frame other than the center-of-mass frame, strings still reconnect but the well-known 90 deg. scattering no longer need correspond to the head-on collision of the strings, due to the breakdown of Lorentz invariance in the underlying noncommutative field theory.
Order preserving vibrating strings and applications to Electrodynamics and
Brenier, Yann
time. It has been advertised as a possible model for dark energy [GKMP]. From a mathematical point specifically to its shallow water version. Then, each vibrating string can be interpreted as a magnetic line
Duality Phase Transition in Type I String Theory
Shyamoli Chaudhuri
2005-09-09T23:59:59.000Z
We show that the duality phase transition in the unoriented type I theory of open and closed strings is_first order_. The order parameter is the semiclassical approximation to the heavy quark-antiquark potential at finite temperature, extracted from the covariant off-shell string amplitude with Wilson loop boundaries wrapped around the Euclidean time direction. Remarkably, precise calculations can be carried out on either side of the phase boundary at the string scale T_C = 1/2\\pi \\alpha^{'1/2} by utilizing the T-dual, type IB and type I', descriptions of the short string gas of massless gluon radiation. We will calculate the change in the duality transition temperature in the presence of an electromagnetic background field.
Effective software testing with a string-constraint solver
Kie?un, Adam
2009-01-01T23:59:59.000Z
This dissertation presents techniques and tools for improving software reliability, by using an expressive string-constraint solver to make implementation-based testing more effective and more applicable. Concolic testing ...
Lovelock black holes in a string cloud background
Tae-Hun Lee; Dharmanand Baboolal; Sushant G. Ghosh
2015-06-11T23:59:59.000Z
We present an exact static, spherically symmetric black hole solution to the third order Lovelock gravity with a string cloud background in seven dimensions for the special case when the second and third order Lovelock coefficients are related via $\\tilde{\\alpha}^2_2=3\\tilde{\\alpha}_3\\;(\\equiv\\alpha^2)$. Further, we examine thermodynamic properties of this black hole to obtain exact expressions for mass, temperature, entropy and also perform the thermodynamic stability analysis. We see that a string cloud background makes a profound influence on horizon structure, thermodynamic properties and the stability of black holes. Interestingly the entropy of the black hole is unaffected due to a string cloud background. However, the critical solution for thermodynamic stability is being affected by a string cloud background.
Quantum hair and the string-black hole correspondence
Gabriele Veneziano
2013-03-28T23:59:59.000Z
We consider a thought experiment in which an energetic massless string probes a "stringhole" (a heavy string lying on the correspondence curve between strings and black holes) at large enough impact parameter for the regime to be under theoretical control. The corresponding, explicitly unitary, $S$-matrix turns out to be perturbatively sensitive to the microstate of the stringhole: in particular, at leading order in $l_s/b$, it depends on a projection of the stringhole's Lorentz-contracted quadrupole moment. The string-black hole correspondence is therefore violated if one assumes quantum hair to be exponentially suppressed as a function of black-hole entropy. Implications for the information paradox are briefly discussed.
D-brane effective field theory from string field theory
Washington Taylor
2000-02-15T23:59:59.000Z
Open string field theory is considered as a tool for deriving the effective action for the massless or tachyonic fields living on D-branes. Some simple calculations are performed in open bosonic string field theory which validate this approach. The level truncation method is used to calculate successive approximations to the quartic terms \\phi^4, (A^\\mu A_\\mu)^2 and [A_\\mu, A_\
Shooting String Holography of Jet Quenching at RHIC and LHC
Andrej Ficnar; Steven S. Gubser; Miklos Gyulassy
2014-11-07T23:59:59.000Z
We derive a new formula for jet energy loss using finite endpoint momentum shooting strings initial conditions in SYM plasmas to overcome the difficulties of previous falling string holographic scenarios. We apply the new formula to compute the nuclear modification factor RAA and the elliptic flow parameter v2 of light hadrons at RHIC and LHC. We show furthermore that Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry improve the agreement with the recent data.
Gravitational field of a stationary circular cosmic string loop
A; A. Sen; N. Banerjee
1998-06-22T23:59:59.000Z
Gravitational field of a stationary circular cosmic string loop has been studied in the context of full nonlinear Einstein's theory of gravity. It has been assumed that the radial and tangential stresses of the loop are equal to the energy density of the string loop. An exact solution for the system has been presented which has a singularity at a finite distance from the axis,but is regular for any other distances from the axis of the loop.
Nonstatic global string in Brans-Dicke theory
A. A. Sen; N. Banerjee
2000-07-19T23:59:59.000Z
Gravitational field of a nonstatic global string has been studied in the context of Brans-Dicke theory of gravity. Both the metric components and the BD scalar field are assumed to be nonseparable functions of time and space.The spacetime may or may not have any singularity at a finite distance from the string core but the singularity at a particular time always remains. It has been shown that the spacetime exhibits both outgoing and incoming gravitational radiation.
Decay of False Vacuum via Fuzzy Monopole in String Theory
Aya Kasai; Yutaka Ookouchi
2015-02-05T23:59:59.000Z
We investigate dielectric branes in false vacua in Type IIB string theory. The dielectric branes are supported against collapsing by lower energy vacua inside spherical or tube-like branes. We claim that such branes can be seeds for semi-classical (or quantum mechanical) decay of the false vacua, which makes the life-time of the false vacua shorter. Also, we discuss a topology change of a bubble corresponding to the fuzzy monopole triggered by dissolving fundamental strings.
The squashed fuzzy sphere, fuzzy strings and the Landau problem
Andronache, Stefan
2015-01-01T23:59:59.000Z
We discuss the squashed fuzzy sphere, which is a projection of the fuzzy sphere onto the equatorial plane, and use it to illustrate the stringy aspects of noncommutative field theory. We elaborate explicitly how strings linking its two coincident sheets arise in terms of fuzzy spherical harmonics. In the large N limit, the matrix-model Laplacian is shown to correctly reproduce the semi-classical dynamics of these charged strings, as given by the Landau problem.
Stirling number Identities and High energy String Scatterings
Jen-Chi Lee; Yi Yang; Sheng-Lan Ko
2009-09-22T23:59:59.000Z
We use Stirling number identities developed recently in number theory to show that ratios among high energy string scattering amplitudes in the fixed angle regime can be extracted from the Kummer function of the second kind. This result not only brings an interesting bridge between string theory and combinatoric number theory but also sheds light on the understanding of algebraic structure of high energy stringy symmetry.
Counting Strings and Phase Transitions in 2D QCD
W. Taylor
1994-05-03T23:59:59.000Z
Several string theories related to QCD in two dimensions are studied. For each of these theories the large $N$ free energy on a (target) sphere of area $A$ is calculated. By considering theories with different subsets of the geometrical structures involved in the full QCD${}_2$ string theory, the different contributions of these structures to the string free energy are calculated using both analytic and numerical methods. The equivalence between the leading terms in the $SU(N)$ and $U(N)$ free energies is simply demonstrated from the string formulation. It is shown that when $\\Omega$-points are removed from the theory, the free energy is convergent for small and large values of $A$ but divergent in an intermediate range. Numerical results indicate that the free energy for the full QCD${}_2$ string fails to converge at the Douglas-Kazakov phase transition point. Similar results for a single chiral sector of the theory, such as has recently been studied by Cordes, Moore, and Ramgoolam, indicate that there are three distinct phases in that theory. These results indicate that from the point of view of the strong coupling phase, the phase transition in the full QCD${}_2$ string arises from the entropy of branch-point singularities.
Ericksen, R.L.
1999-10-28T23:59:59.000Z
There is an unsurpassed lack of scientific data with respect to the concentrations and isotopic compositions of uranium, thorium, and radium in the produced formation fluids (brine), precipitates, and sludges generated with the operation of oil and gas wells in Mississippi. These radioactive elements when contained in the formation fluids have been given the term NORM, which is an acronym for naturally occurring radioactive materials. When they are technologically enhanced during oil and gas production activities resulting in the formation of scale (precipitates) and sludges they are termed TENORM (technologically enhanced naturally occurring radioactive materials). As used in this document, NORM and TENORM will be considered equivalent terms and the occurrence of NORM in the oilfield will be considered the result of production operations. As a result of the lack of data no scientifically sound theses may be developed concerning the presence of these radionuclides in the fluid brine, precipitate (scale), or sludge phases. Over the period of just one year, 1997 for example, Mississippi produced over 39,372,963,584 liters (10,402,368,186 gallons or 247,675,433 barrels) of formation water associated with hydrocarbon production from 41 counties across the state.
Das, N.; Horita, J.; Holland, H.D. (Harvard Univ., Cambridge, MA (USA))
1990-02-01T23:59:59.000Z
Fluid was extracted from 18 fluid inclusions in halite of the Late Silurian Salina Group exposed in the Crystal Mine on the outskirts of Detroit, Michigan. Compared with modern seawater evaporated to the same degree, the inclusion fluids are severely depleted in SO{sub 4}{sup {minus}2}, somewhat depleted in Na{sup +} and Mg{sup +2}, and greatly enriched in Ca{sup +2}. The composition of the inclusion fluids can be derived from Silurian seawater with a composition close to that of modern seawater, if it is assumed that the composition of the Silurian seawater was modified by dolomitizing CaCO{sub 3}-rich sediments and by albitizing silicate minerals during its evolution into evaporite brines. Since the evolution of the brines involved a number of chemical reactions, it is impossible to recover the initial concentration of all of the major ions in the parent Silurian seawater from the composition of the inclusion fluids alone. It is likely, however, that the m{sub K+}/m{sub Br-} ratio and the functions in Late Silurian seawater had values close to those of modern seawater. Measurements of the isotopic composition of sulfur and of Sr in anhydrite within and associated with the halite host of the fluid inclusions are consistent with previous measurements of {delta}{sup 34}S in Silurian marine anhydrites and with the {sup 87}Sr/{sup 86}Sr ratios of Late Silurian marine carbonates.
P. C. Myint; Y. Hao; A. Firoozabadi
2015-04-20T23:59:59.000Z
Thermodynamic property calculations of mixtures containing carbon dioxide (CO$_2$) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi, and the CO$_2$ activity coefficient model by Duan and Sun. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO$_2$, pure water, and both CO$_2$-rich and aqueous (H$_2$O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun's model yields accurate results for the partial molar enthalpy of CO$_2$. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H$_2$O-CO$_2$-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.
The Wavelet Trie: Maintaining an Indexed Sequence of Strings in Compressed Space
Grossi, Roberto
2012-01-01T23:59:59.000Z
An indexed sequence of strings is a data structure for storing a string sequence that supports random access, searching, range counting and analytics operations, both for exact matches and prefix search. String sequences lie at the core of column-oriented databases, log processing, and other storage and query tasks. In these applications each string can appear several times and the order of the strings in the sequence is relevant. The prefix structure of the strings is relevant as well: common prefixes are sought in strings to extract interesting features from the sequence. Moreover, space-efficiency is highly desirable as it translates directly into higher performance, since more data can fit in fast memory. We introduce and study the problem of compressed indexed sequence of strings, representing indexed sequences of strings in nearly-optimal compressed space, both in the static and dynamic settings, while preserving provably good performance for the supported operations. We present a new data structure for...
Final Report String Phenomenology 2011: The Tenth Annual Meeting on String Phenomenology
Shiu, Gary; Everett, Lisa
2011-08-26T23:59:59.000Z
The Tenth Annual International String Phenomenology Conference was held at the University of Wisconsin, Madison on August 22-26, 2011. The Conference was organized by Profs. Gary Shiu and Lisa Everett, with the help of two postdoctoral fellows Heng-Yu Chen and Jiajun Xu. The scientific subjects of the talks and discussions were chosen to be widely interdisciplinary, reflecting the scope and maturity of the field. The conference brought together researchers of diverse subfields in physics and mathematics to present and discuss recent developments in connecting observable particle physics and cosmology with the domain of fundamental theory. This report summarizes the outcome of this conference.
Integrable Deformations of Strings on Symmetric Spaces
Timothy J. Hollowood; J. Luis Miramontes; David M. Schmidtt
2014-07-16T23:59:59.000Z
A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on R x F/G via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 x S5.
String GUT scenarios with stabilized moduli
Blumenhagen, Ralph; Moster, Sebastian; Plauschinn, Erik [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany)
2008-09-15T23:59:59.000Z
Taking into account the recently proposed poly-instanton corrections to the superpotential and combining the racetrack with a Kachru-Kallosh-Linde-Trivedi, respectively, large volume scenario in an intricate manner, we show that we gain exponential control over the parameters in an effective superpotential. This allows us to dynamically stabilize moduli such that a conventional minimal supersymmetric standard model scenario with the string scale lowered to the grand unified theory scale is realized. Depending on the cycles wrapped by the minimal supersymmetric standard model branes, two different scenarios for the hierarchy of soft masses arise. The first one is a supergravity mediated model with M{sub 3/2}{approx_equal}1 TeV while the second one features mixed anomaly supergravity mediation with M{sub 3/2}{approx_equal}10{sup 10} GeV and split supersymmetry. We also comment on dynamically lowering the scales such that the tree level cosmological constant is of the order {lambda}=(10{sup -3} eV){sup 4}.
What is the maximum rate at which entropy of a string can increase?
Ropotenko, Kostyantyn [State Administration of Communications, Ministry of Transport and Communications of Ukraine 22, Khreschatyk, 01001, Kyiv (Ukraine)
2009-03-15T23:59:59.000Z
According to Susskind, a string falling toward a black hole spreads exponentially over the stretched horizon due to repulsive interactions of the string bits. In this paper such a string is modeled as a self-avoiding walk and the string entropy is found. It is shown that the rate at which information/entropy contained in the string spreads is the maximum rate allowed by quantum theory. The maximum rate at which the black hole entropy can increase when a string falls into a black hole is also discussed.
Fully Anisotropic String Cosmologies, Maxwell Fields and Primordial Shear
Massimo Giovannini
1998-12-07T23:59:59.000Z
We present a class of exact cosmological solutions of the low energy string effective action in the presence of a homogeneous magnetic fields. We discuss the physical properties of the obtained (fully anisotropic) cosmologies paying particular attention to their vacuum limit and to the possible isotropization mechanisms. We argue that quadratic curvature corrections are able to isotropize fully anisotropic solutions whose scale factors describe accelerated expansion. Moreover, the degree of isotropization grows with the duration of the string phase. We follow the fate of the shear parameter in a decelerated phase where, dilaton, magnetic fields and radiation fluid are simultaneously present. In the absence of any magnetic field a long string phase immediately followed by radiation is able to erase large anisotropies. Conversely, if a short string phase is followed by a long dilaton dominated phase the anisotropies can be present, in principle, also at later times. The presence of magnetic seeds after the end of the string phase can induce further anisotropies which can be studied within the formalism reported in this paper.
Bacon, Diana H.
2013-03-31T23:59:59.000Z
The National Risk Assessment Partnership (NRAP) consists of 5 U.S DOE national laboratories collaborating to develop a framework for predicting the risks associated with carbon sequestration. The approach taken by NRAP is to divide the system into components, including injection target reservoirs, wellbores, natural pathways including faults and fractures, groundwater and the atmosphere. Next, develop a detailed, physics and chemistry-based model of each component. Using the results of the detailed models, develop efficient, simplified models, termed reduced order models (ROM) for each component. Finally, integrate the component ROMs into a system model that calculates risk profiles for the site. This report details the development of the Groundwater Geochemistry ROM for the Edwards Aquifer at PNNL. The Groundwater Geochemistry ROM for the Edwards Aquifer uses a Wellbore Leakage ROM developed at LANL as input. The detailed model, using the STOMP simulator, covers a 5x8 km area of the Edwards Aquifer near San Antonio, Texas. The model includes heterogeneous hydraulic properties, and equilibrium, kinetic and sorption reactions between groundwater, leaked CO2 gas, brine, and the aquifer carbonate and clay minerals. Latin Hypercube sampling was used to generate 1024 samples of input parameters. For each of these input samples, the STOMP simulator was used to predict the flux of CO2 to the atmosphere, and the volume, length and width of the aquifer where pH was less than the MCL standard, and TDS, arsenic, cadmium and lead exceeded MCL standards. In order to decouple the Wellbore Leakage ROM from the Groundwater Geochemistry ROM, the response surface was transformed to replace Wellbore Leakage ROM input parameters with instantaneous and cumulative CO2 and brine leakage rates. The most sensitive parameters proved to be the CO2 and brine leakage rates from the well, with equilibrium coefficients for calcite and dolomite, as well as the number of illite and kaolinite sorption sites proving to be of secondary importance. The Groundwater Geochemistry ROM was developed using nonlinear regression to fit the response surface with a quadratic polynomial. The goodness of fit was excellent for the CO2 flux to the atmosphere, and very good for predicting the volumes of groundwater exceeding the pH, TDS, As, Cd and Pb threshold values.
Broader source: Energy.gov [DOE]
Project objectives: Generate and characterize mineral dissolution/precipitation reactions in supercritical CO2/brine/rock systems under pressure-temperature-chemistry conditions resembling CO2injection into EGS. Characterize three-dimensional spatial and temporal distributions of rock structures subject to mineral dissolution/precipitation processes by X-ray tomography, SEM imaging, and Microprobe analysis.
94 LITHIUM (Data in metric tons of lithium content unless otherwise noted) Domestic Production and Use: The only active lithium carbonate plant in the United States was a brine operation in Nevada. Two companies produced a large array of downstream lithium compounds in the United States from domestic or South
V-075: EMC AlphaStor Command Injection and Format String Flaws...
Broader source: Energy.gov (indexed) [DOE]
5: EMC AlphaStor Command Injection and Format String Flaws Let Remote Users Execute Arbitrary Code V-075: EMC AlphaStor Command Injection and Format String Flaws Let Remote Users...
A New Lorentz Violating Nonlocal Field Theory From String-Theory
Ganor, Ori J.
2009-01-01T23:59:59.000Z
hep-th/9908019]. [29] J. Polchinski, “String theory. Vol.2: Superstring theory and beyond,” [30] S. Chakravarty, K.Violating Nonlocal Field Theory From String-Theory Ori J.
Wilson lines for AdS_5 black strings
Kiril Hristov; Stefanos Katmadas
2014-12-03T23:59:59.000Z
We describe a simple method of extending AdS_5 black string solutions of 5d gauged supergravity in a supersymmetric way by addition of Wilson lines along a circular direction in space. When this direction is chosen along the string, and due to the specific form of 5d supergravity that features Chern-Simons terms, the existence of magnetic charges automatically generates conserved electric charges in a 5d analogue of the Witten effect. Therefore we find a rather generic, model-independent way of adding electric charges to already existing solutions with no backreaction from the geometry or breaking of any symmetry. We use this method to explicitly write down more general versions of the Benini-Bobev black strings and comment on the implications for the dual field theory and the similarities with generalizations of the Cacciatori-Klemm black holes in AdS_4.
Axion inflation and gravity waves in string theory
Kallosh, Renata; Sivanandam, Navin; Soroush, Masoud [Institute for Theoretical Physics, Department of Physics, Stanford University, Stanford, California 94305-4060 (United States)
2008-02-15T23:59:59.000Z
The majority of models of inflation in string theory predict an absence of measurable gravitational waves, r<<10{sup -3}. The most promising proposals for making string theoretic models that yield measurable tensor fluctuations involve axion fields with slightly broken shift symmetry. We consider such models in detail, with a particular focus on the N-flation scenario and on axion valley/natural inflation models. We find that in Calabi-Yau threefold compactifications with logarithmic Kaehler potentials K it appears to be difficult to meet the conditions required for axion inflation in the supergravity regime. However, in supergravities with an (approximately) quadratic shift-symmetric K, axion inflation may be viable. Such Kaehler potentials do arise in some string models, in specific limits of the moduli space. We describe the most promising classes of models; more detailed study will be required before one can conclude that working models exist.
Jet signals for low mass strings at the LHC
Luis A. Anchordoqui; Haim Goldberg; Satoshi Nawata; Tomasz R. Taylor
2008-04-22T23:59:59.000Z
The mass scale M_s of superstring theory is an arbitrary parameter that can be as low as few TeVs if the Universe contains large extra dimensions. We propose a search for the effects of Regge excitations of fundamental strings at LHC, in the process p p \\to \\gamma jet. The underlying parton process is dominantly the single photon production in gluon fusion, g g \\to \\gamma g, with open string states propagating in intermediate channels. If the photon mixes with the gauge boson of the baryon number, which is a common feature of D-brane quivers, the amplitude appears already at the string disk level. It is completely determined by the mixing parameter -- and it is otherwise model-(compactification-) independent. Even for relatively small mixing, 100 fb^{-1} of LHC data could probe deviations from standard model physics, at a 5\\sigma significance, for M_s as large as 3.3 TeV.
Clouds of strings in third-order Lovelock gravity
Sushant G. Ghosh; Uma Papnoi; Sunil D. Maharaj
2014-08-20T23:59:59.000Z
Lovelock theory is a natural extension of the Einstein theory of general relativity to higher dimensions in which the first and second orders correspond, respectively, to general relativity and Einstein-Gauss-Bonnet gravity. We present exact black hole solutions of $D\\geq 4$-dimensional spacetime for first-, second-, and third-order Lovelock gravities in a string cloud background. Further, we compute the mass, temperature, and entropy of black hole solutions for the higher-dimensional general relativity and Einstein-Gauss-Bonnet theories and also perform thermodynamic stability of black holes. It turns out that the presence of the Gauss-Bonnet term and/or background string cloud completely changes the black hole thermodynamics. Interestingly, the entropy of a black hole is unaffected due to a background string cloud. We rediscover several known spherically symmetric black hole solutions in the appropriate limits.
Theoretical Research in Cosmology, High-Energy Physics and String Theory
Ng, Y Jack; Dolan, Louise; Mersini-Houghton, Laura; Frampton, Paul
2013-07-29T23:59:59.000Z
The research was in the area of Theoretical Physics: Cosmology, High-Energy Physics and String Theory
Possible influence of the two string events on the hadron formation in a nuclear environment
N. Akopov; L. Grigoryan; Z. Akopov
2007-05-07T23:59:59.000Z
One of the basic assumptions of the string model is that as a result of a DIS in nucleus a single string arises, which then breaks into hadrons. However the pomeron exchange considered in this work, leads to the production of two strings in the one event. The hadrons produced in these events have smaller formation lengths, than those with the same energy produced in the single string events. As a consequence, they undergo more substantial absorption in the nuclear matter.
Possible influence of the two string events on the hadron formation in a nuclear environment
Akopov, N; Akopov, Z
2007-01-01T23:59:59.000Z
One of the basic assumptions of the string model is that as a result of a DIS in nucleus a single string arises, which then breaks into hadrons. However the pomeron exchange considered in this work, leads to the production of two strings in the one event. The hadrons produced in these events have smaller formation lengths, than those with the same energy produced in the single string events. As a consequence, they undergo more substantial absorption in the nuclear matter.
Farmer, J C
2008-11-25T23:59:59.000Z
Several hard, corrosion-resistant and neutron-absorbing iron-based amorphous alloys have now been developed that can be applied as thermal spray coatings. These new alloys include relatively high concentrations of Cr, Mo, and W for enhanced corrosion resistance, and substantial B to enable both glass formation and neutron absorption. The corrosion resistances of these novel alloys have been compared to that of several austenitic alloys in a broad range of synthetic brines, with and without nitrate inhibitor, at elevated temperature. Linear polarization and electrochemical impedance spectroscopy have been used for in situ measurement of corrosion rates for prolonged periods of time, while scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX) have been used for ex situ characterization of samples at the end of tests. The application of these new coatings for the protection of spent nuclear fuel storage systems, equipment in nuclear service, steel-reinforced concrete will be discussed.
Myint, P C; Firoozabadi, A
2015-01-01T23:59:59.000Z
Thermodynamic property calculations of mixtures containing carbon dioxide (CO$_2$) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi, and the CO$_2$ activity coefficient model by Duan and Sun. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO$_2$, pure water, and both CO$_2$-rich and aqueous (H$_2$O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spy...
Quantum Charged Non-Linear Nano-String and Quantum Vacuum
F. Kheirandish; M. Amooshahi
2005-07-20T23:59:59.000Z
The classical and quantum dynamic of a nonlinear chareged vibrating string and its interaction with quantum vacuum field is investigated. Some probability amplitudes for transitions between vacuum field and quantum states of the string are obtained. The effect of nonlinearity on some probability amplitudes is investigated and finally the corect equation for string containing the vacuum and radiation reaction field is obtained.
Sister trajectories and locality in multiloop string scattering
Carbon, S.L. (ACTA Inc., 505 N. Orlando Avenue, Mez 3, Cocoa Beach, Florida 32931 (United States))
1995-04-15T23:59:59.000Z
The multiloop corrections to the high energy behavior of four-tachyon scattering are studied in string theory. In the limit of high center-of-mass energy, [ital s][r arrow][infinity], for fixed transfer momentum squared, [ital t], we obtain the Regge behavior of the first sister'' trajectory in two-loop scattering. The multiloop-generated sisters are found to be independent of propagator twists, which are necessary for exposing tree-level sisters. The presence of these trajectories in higher order loop diagrams may be sufficient for string theory to be consistent nonperturbatively with locality.
Physical Interpretation of the 26 Dimensions of Bosonic String Theory
Frank D. Smith Jr
2002-07-15T23:59:59.000Z
The 26 dimensions of Closed Unoriented Bosonic String Theory are interpreted as the 26 dimensions of the traceless Jordan algebra J3(O)o of 3x3 Octonionic matrices, with each of the 3 Octonionic dimenisons of J3(O)o having the following physical interpretation: 4-dimensional physical spacetime plus 4-dimensional internal symmetry space; 8 first-generation fermion particles; 8 first-generation fermion anti-particles. This interpretation is consistent with interpreting the strings as World Lines of the Worlds of Many-Worlds Quantum Theory and the 26 dimensions as the degrees of freedom of the Worlds of the Many-Worlds.
Kerr-NUT-AdS metrics and string theory
Chen, Wei
2009-05-15T23:59:59.000Z
are then described as the exchanges of gauge bosons in an SU(3)?SU(2)?U(1) symmetry group. The Standard Model is quite successful in explaining the experimental data, and in fact it agrees with all of our observations of the physical world. However, a major problem..., string theory has been deemed to be a very promising can- didate for the unification theory of everything. The spectrum of bosonic particles may be explained as the various excitations of strings, and this spectrum automat- ically contains a massless spin...
Kerr-NUT-AdS metrics and string theory
Chen, Wei
2008-10-10T23:59:59.000Z
are then described as the exchanges of gauge bosons in an SU(3)×SU(2)×U(1) symmetry group. The Standard Model is quite successful in explaining the experimental data, and in fact it agrees with all of our observations of the physical world. However, a major problem..., string theory has been deemed to be a very promising can- didate for the unification theory of everything. The spectrum of bosonic particles may be explained as the various excitations of strings, and this spectrum automat- ically contains a massless spin...
A classical instability for black strings and p-branes
Gregory, R. (Chicago Univ., IL (United States). Enrico Fermi Inst.); Laflamme, R. (Los Alamos National Lab., NM (United States))
1993-01-01T23:59:59.000Z
We investigate the evolution of small perturbations around black of strings and branes which are low energy solutions of string theory. For simplicity we focus attention on the zero charge case and show that there are unstable modes for a range of time frequency and wavelength in the extra 10 - D dimensions. These perturbations can be stabilized if the extra dimensions are compactified to a scale smaller than the minimum wavelength for which instability occurs and thus will not affect large astrophysical black holes in four dimensions. We comment on the implications of this result for the Cosmic Censorship Hypothesis
A classical instability for black strings and p-branes
Gregory, R. [Chicago Univ., IL (United States). Enrico Fermi Inst.; Laflamme, R. [Los Alamos National Lab., NM (United States)
1993-06-01T23:59:59.000Z
We investigate the evolution of small perturbations around black of strings and branes which are low energy solutions of string theory. For simplicity we focus attention on the zero charge case and show that there are unstable modes for a range of time frequency and wavelength in the extra 10 - D dimensions. These perturbations can be stabilized if the extra dimensions are compactified to a scale smaller than the minimum wavelength for which instability occurs and thus will not affect large astrophysical black holes in four dimensions. We comment on the implications of this result for the Cosmic Censorship Hypothesis
Coset Symmetries in Dimensionally Reduced Bosonic String Theory
N. D. Lambert; P. C. West
2001-08-02T23:59:59.000Z
We discuss the dimensional reduction of various effective actions, particularly that of the closed Bosonic string and pure gravity, to two and three dimensions. The result for the closed Bosonic string leads to coset symmetries which are in agreement with those recently predicted and argued to be present in a new unreduced formulation of this theory. We also show that part of the Geroch group appears in the unreduced duality symmetric formulation of gravity recently proposed. We conjecture that this formulation can be extended to a non-linear realisation based on a Kac-Moody algebra which we identify. We also briefly discuss the proposed action of Bosonic M-theory.
Note on Structure Formation from Cosmic String Wakes
Duplessis, Francis
2013-01-01T23:59:59.000Z
The search for cosmic strings has been of renewed interest with the advent of precision cosmology. In this note we give a quantitative description of the nonlinear matter density fluctuations that can form from a scaling network of cosmic string wakes. Specifically, we compute the distribution of dark matter halos. These halos would possess strong correlations in position space that should have survived until today. We also discuss the challenges involved in their detection due to their small size and the complex dynamics of their formation.
A note on the string spectrum at the Hagedorn temperature
J. D. Madrigal; P. Talavera
2009-05-21T23:59:59.000Z
We discuss semi-classical string configurations at finite temperature. We find that those soliton solution in the background describing type IIA strings disappear or become divergent when we approach the Hagedorn temperature in the strong coupling regime. These findings together with a semi-classical analysis for the Hawking radiation let us to think that Hawking radiation is mainly driven by the existence of highly excited states. As by side, we check that beside the thermodynamical instability the system is dynamical unstable before reaching the Hagedorn temperature.
Investigation of single unit flashovers in HVDC insulator strings
Ishikawa, Kouichi; Kageyama, Hiroshi; Yamada, Yasuhiro [Kansai Electric Power Co., Inc., Osaka (Japan)] [Kansai Electric Power Co., Inc., Osaka (Japan); Matsuoka, Ryosuke; Ito, Susumu; Sakanishi, Kenji [NGK Insulators, Ltd., Nagoya (Japan)] [NGK Insulators, Ltd., Nagoya (Japan)
1996-10-01T23:59:59.000Z
In HVDC transmission lines, a special phenomenon, so called single unit flashover, is observed under some special conditions. Only one or two insulator units repeat flashovers, not resulting in an overall flashover along the string. However, higher magnitudes of audible noise, radio and television interferences, may give a serious problem. Based on the investigation on {+-}500-kV full scale insulator strings, higher occurrence probability of single unit flashovers under cold-wet-switch-on conditions was clarified compared with normal continuous operating voltage conditions. Effectiveness of the newly proposed countermeasures to prevent single unit flashovers was demonstrated by experiments in laboratory and in field.
Kerr-NUT-AdS metrics and string theory
Chen, Wei
2008-10-10T23:59:59.000Z
are then described as the exchanges of gauge bosons in an SU(3)×SU(2)×U(1) symmetry group. The Standard Model is quite successful in explaining the experimental data, and in fact it agrees with all of our observations of the physical world. However, a major problem..., string theory has been deemed to be a very promising can- didate for the unification theory of everything. The spectrum of bosonic particles may be explained as the various excitations of strings, and this spectrum automat- ically contains a massless spin...
Kerr-NUT-AdS metrics and string theory
Chen, Wei
2009-05-15T23:59:59.000Z
are then described as the exchanges of gauge bosons in an SU(3)?SU(2)?U(1) symmetry group. The Standard Model is quite successful in explaining the experimental data, and in fact it agrees with all of our observations of the physical world. However, a major problem..., string theory has been deemed to be a very promising can- didate for the unification theory of everything. The spectrum of bosonic particles may be explained as the various excitations of strings, and this spectrum automat- ically contains a massless spin...
On the short string limit of the folded spinning string in AdS5 x S5
M. Beccaria; A. Tirziu
2008-10-23T23:59:59.000Z
In this paper we generalize the results of arXiv:0806.4758 to non-zero value J of angular momentum in S^5. We compute the 1-loop correction to the energy of the folded spinning string in AdS_5 x S^5 in the particular limit of slow short string approximation. In this limit the string is moving in a near-flat central region of AdS_5 slowly rotating in both AdS_5 and S^5. The one-loop correction should represent the first subleading correction to strong coupling expansion of the anomalous dimension of short gauge theory operators of the form Tr D^S Z^J in the SL(2) sector.
Offutt, Jeff
a list of strings to be randomly chosen with two options: with replacement or without replacement of strings and choosing them randomly with two options: with replacement or without replacement (default strings are separated by carriage return. 2. User selects to randomly choose strings `without replacement
Finite Temperature Bosonic Closed Strings: Thermal Duality and the Kosterlitz Thouless Transition
S. Chaudhuri
2005-09-12T23:59:59.000Z
We elucidate the properties of a gas of free closed bosonic strings in thermal equilibrium. Our starting point is the intensive generating functional of connected one-loop closed vacuum string graphs given by the Polyakov path integral. Invariance of the path integral under modular transformations gives a thermal duality invariant expression for the free energy of free closed strings at finite temperature. The free bosonic string gas exhibits a self-dual Kosterlitz-Thouless phase transition. The thermodynamic potentials of the gas of free bosonic closed strings are shown to exhibit an infinite hierarchy of thermal self-duality relations. Note Added (Sep 2005).
Brane cosmic string compactification in Brans-Dicke theory
Abdalla, M. C. B.; Hoff da Silva, J. M. [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145 01405-900 Sao Paulo, SP (Brazil); Guimaraes, M. E. X. [Departamento de Matematica, Universidade de Brasilia, Asa Norte 70910-900, Brasilia-DF (Brazil)
2007-04-15T23:59:59.000Z
We investigate an alternative compactification of extra dimensions using local cosmic string in the Brans-Dicke gravity framework. In the context of dynamical systems it is possible to show that there exist a stable field configuration for the Einstein-Brans-Dicke equations. We explore the analogies between this particular model and the Randall-Sundrum scenario.
Introduction to conformal field theory and string theory
Dixon, L.J.
1989-12-01T23:59:59.000Z
These lectures are meant to provide a brief introduction to conformal field theory (CFT) and string theory for those with no prior exposure to the subjects. There are many excellent reviews already available, and most of these go in to much more detail than I will be able to here. 52 refs., 11 figs.
String Organization of Field Theories: Duality and Gauge Invariance
Y. J. Feng; C. S. Lam
1994-09-14T23:59:59.000Z
String theories should reduce to ordinary four-dimensional field theories at low energies. Yet the formulation of the two are so different that such a connection, if it exists, is not immediately obvious. With the Schwinger proper-time representation, and the spinor helicity technique, it has been shown that field theories can indeed be written in a string-like manner, thus resulting in simplifications in practical calculations, and providing novel insights into gauge and gravitational theories. This paper continues the study of string organization of field theories by focusing on the question of local duality. It is shown that a single expression for the sum of many diagrams can indeed be written for QED, thereby simulating the duality property in strings. The relation between a single diagram and the dual sum is somewhat analogous to the relation between a old- fashioned perturbation diagram and a Feynman diagram. Dual expressions are particularly significant for gauge theories because they are gauge invariant while expressions for single diagrams are not.
Grand Unification as a Bridge Between String Theory and Phenomenology
Pati, Jogesh C.
2006-06-09T23:59:59.000Z
In the first part of the talk, I explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity--be it string/M theory or a reincarnation--this evidence then suggests that such a theory should lead to an effective grand unification-like symmetry as above in 4D, near the string-GUT-scale, rather than the standard model symmetry. Advantages of an effective supersymmetric G(224) = SU(2){sub L} x SU(2){sub R} x SU(4){sup c} or SO(10) symmetry in 4D in explaining (1) observed neutrino oscillations, (2) baryogenesis via leptogenesis, and (3) certain fermion mass-relations are noted. And certain distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and flavor violations (as in {mu} {yields} e{gamma}, {tau} {yields} {mu}{gamma}, edm's of the neutron and the electron) as well as proton decay are briefly mentioned. Recalling some of the successes we have had in our understanding of nature so far, and the current difficulties of string/M theory as regards the large multiplicity of string vacua, some comments are made on the traditional goal of understanding vis a vis the recently evolved view of landscape and anthropism.
Effective string theory description of the interface free energy
M. Billo; M. Caselle; L. Ferro; M. Hasenbusch; M. Panero
2007-10-09T23:59:59.000Z
We compare the predictions of the Nambu-Goto effective string model with a set of high precision Monte Carlo results for interfaces with periodic boundary conditions in the 3D Ising model. We compute the free energy in the covariant gauge exactly, up to the inclusion of the Liouville mode. The perturbative expansion of this result agrees both with the result evaluated several years ago by Dietz and Filk in the physical gauge and with a recent calculation with the Polchinski-Strominger action. We also derive the effective string spectrum which, because of the different boundary conditions, is very different from the well known one of Arvis. Taking into proper account the effective string corrections and exploiting some technical improvements in the simulations we obtain precise estimate of the amplitude ratios T_c/\\sqrt{sigma}, m_{0++}/\\sqrt{\\sigma} and sigma xi_{2nd}^2. We also discuss the behaviour of the effective string free energy in the dimensional reduction limit (i.e., near the deconfinement transition of the dual 3d gauge Ising model) and its relationship with the 2d Ising model interfaces
Landau Quantization in the Spinning Cosmic String Spacetime
Celio R. Muniz; Valdir B. Bezerra; Marcony S. Cunha
2014-03-26T23:59:59.000Z
We analyze the quantum phenomenon arising from the interaction of a spinless charged particle with a rotating cosmic string, under the action of a static and uniform magnetic field parallel to the string. We calculate the energy levels of the particle in the non-relativistic approach, showing how these energies depend on the parameters involved in the problem. In order to do this, we solve the time independent Schroedinger equation in the geometry of the spinning cosmic string, taking into account that the coupling between the rotation of the spacetime and the angular momentum of the particle is very weak, such that makes sense to apply the Schr\\"odinger equation in a curved background whose metric has an off diagonal term which involves time and space. It is also assumed that the particle orbits sufficiently far from the boundary of the region of closed timelike curves which exist around this topological defect. Finally, we find the Landau levels of the particle in the presence of a spinning cosmic string endowed with internal structure, i.e., having finite width and uniformly filled with both material and vacuum energies.
Classification of Flipped SU(5) Heterotic-String Vacua
Alon E. Faraggi; John Rizos; Hasan Sonmez
2014-03-31T23:59:59.000Z
We extend the classification of the free fermionic heterotic-string vacua to models in which the SO(10) GUT symmetry at the string scale is broken to the flipped SU(5) subgroup. In our classification method, the set of basis vectors defined by the boundary conditions which are assigned to the free fermions is fixed and the enumeration of the string vacua is obtained in terms of the Generalised GSO (GGSO) projection coefficients entering the one-loop partition function. We derive algebraic expressions for the GGSO projections for all the physical states appearing in the sectors generated by the set of basis vectors. This enables the analysis of the entire string spectrum to be programmed in to a computer code therefore, we performed a statistical sampling in the space of 2^{44} (approximately 10^{13}) flipped $SU(5)$ vacua and scanned up to 10^{12} GGSO configurations. For that purpose, two independent codes were developed based on JAVA and FORTRAN95. All the results presented here are confirmed by the two independent routines. Contrary to the corresponding Pati-Salam classification, we do not find exophobic flipped SU(5) vacua with an odd number of generations. We study the structure of exotic states appearing in the three generation models that additionally contain a viable Higgs spectrum. Moreover, we demonstrate the existence of models in which all the exotic states are confined by a hidden sector non-Abelian gauge symmetry as well as models that may admit the racetrack mechanism.
HBT puzzle at RHIC AMPT model with String Melting
Lin, Zi-wei
/RsideSmall radii Small duration time dt by Stephen Johnson at RWW02 One way out: Hydro Softest point in EOS Measured extensively in heavy ion collisions reasonably described by models (hydro-ph/01120062 recent hydro studies: #12;HIJING energy in strings(soft) and minijet partons(hard) ZPC (Zhang
The vacuum state functional of interacting string field theory
A. Ilderton
2005-06-21T23:59:59.000Z
We show that the vacuum state functional for both open and closed string field theories can be constructed from the vacuum expectation values it must generate. The method also applies to quantum field theory and as an application we give a diagrammatic description of the equivalance between Schrodinger and covariant repreresentations of field theory.
Combinatorial Problems on Strings with Applications to Protein Folding
Newman, Alantha
Combinatorial Problems on Strings with Applications to Protein Folding Alantha Newman MIT San Jose, CA 95120, USA ruhl@almaden.ibm.com Abstract We consider the problem of protein folding in linear time. 1 Introduction We consider the problem of protein folding in the HP model on the three
Holography and the Canonical Ensemble of Fermionic Strings
Shyamoli Chaudhuri
2005-09-12T23:59:59.000Z
We show that the canonical ensemble in any of the six supersymmetric string theories, type IIA and IIB, type IB and type I', or heterotic E_8 x E_8 and Spin(32)/Z_2, exhibits a strong version of holography: the growth of the number of degrees of freedom in the free energy at high temperatures is identical to that in a two-dimensional quantum field theory. We clarify the precise nature of the thermal duality phase transition in each case, confirming that it lies within the Kosterlitz-Thouless universality class. We show that, in the presence of Dbranes, and a consequent Yang-Mills gauge sector, the thermal ensemble of type II strings is infrared stable, with neither tachyons nor massless scalar tadpoles. Supersymmetry remains unbroken in the oriented closed string sector, but is broken by thermal effects in the full unoriented open and closed type I string theory. We identify an order parameter for an unusual phase transition in the worldvolume gauge theory signalled by the short distance behavior of the pair correlator of timelike Wilson loops. Note Added (Sep 2005).
Kazuyuki Furuuchi
2008-06-30T23:59:59.000Z
Closed string field theory is constructed by stochastically quantizing a matrix model for Polyakov loops that describes phases of a large N gauge theory at finite temperature. Coherent states in this string field theory describes winding string condensation which has been expected to cause a topology change from thermal AdS geometry to AdS-Schwarzschild black hole geometry. D-branes in this closed string field theory is also discussed. Slightly extended version of a talk given at CosPA 2007, Nov.13-15, Taipei, Taiwan.
Haszeldine, Stuart
24/02/2012 12:49SPE Projects, Facilities & Construction - CO2/Brine Surface Dissolution of Petroleum Engineers SPE Projects, Facilities & Construction Volume 6, Number 1, March 2011, pp. 41-53 SPE
DeRouen, L.R.; Hann, R.W.; Casserly, D.M.; Giammona, C.; Lascara, V.J. (eds.)
1983-02-01T23:59:59.000Z
This project centers around the Strategic Petroleum Site (SPR) known as the West Hackberry salt dome which located in southwestern Louisiana, and which is designed to store 241 million barrels of crude oil. Oil storage caverns are formed by injecting water into salt deposits, and pumping out the resulting brine. Studies described in this report were designed as follow-on studies to three months of pre-discharge characterization work, and include data collected during the first year of brine leaching operations. The objectives were to: (1) characterize the environment in terms of physical, chemical and biological attributes; (2) determine if significant adverse changes in ecosystem productivity and stability of the biological community are occurring as a result of brine discharge; and (3) determine the magnitude of any change observed. Volume V contains appendices for the following: supporting data for estuarine hydrology and hydrography; supporting data analysis of discharge plume; supporting data for water and sediment chemistry; CTD/DO and pH profiles during biological monitoring; supporting data for nekton; and supporting data for data management.
Integrated Solar Upper Stage (ISUS) thermionic converter string evaluation
Talbot, G.J.; Ramsey, W.D.; Chao, C.J.
1998-07-01T23:59:59.000Z
A serial string of eighth (8) thermionic converters were performance tested at New Mexico Engineering Research Institute (NMERI) by Frank Wyant et al1. The tests results from the second String Thermionic Assembly Research Testbed (START II) produced less than one half the expected power based on individual converter performance tests. Seven of the eight converters were returned to Lockheed Martin Information Systems-EOS for performance evaluation. Six of the seven produced nominal performance while the seventh converter showed a drastic reduction in performance due to a cesium leak to atmosphere. Several models were proposed to explain why the individual converter performance differed so markedly from the START II serial array. This paper discusses the models, evaluates model validity and compares the models with results from a tow converter serial test using of the returned START II converters.
Gamma-ray bursts, axion emission and string theory dilaton
O. Bertolami
1999-01-14T23:59:59.000Z
The emission of axions from supernovae is an interesting possibility to account for the Gamma-Ray Bursts provided their energy can be effectively converted into electromagnetic energy elsewhere. The connection between supernova and gamma-ray bursts has been recently confirmed by the observed correlation between the burst of April 25, 1998 and the supernova SN1998bw. We argue that the axion convertion into photons can be more efficient if one considers the coupling between an intermediate scale axion and the string theory dilaton along with the inclusion of string loops. We also discuss the way dilaton dynamics may allow for a more effective energy exchange with electromagnetic radiation in the expansion process of fireballs.
Low-l CMB Power Loss in String Inflation
Francisco G. Pedro; Alexander Westphal
2013-09-13T23:59:59.000Z
The lack of power on large scales (l < 40) might have been observed by the PLANCK satellite. We argue that this putative feature can be explained by a phase of fast roll at the onset of inflation. We show that in the context of single field models what is required is an asymmetric inflection point model of which fibre inflation is a string motivated example. We study the ability of fibre inflation to generate a suppression of the CMB 2-point function power at low l, finding that the potential derived from string loops is not steep enough for this purpose. We introduce a steeper contribution to the potential, that dominates away from the inflationary region, and show that if properly tuned it can indeed lead to a spectrum with lack of power at large scales.
Gauge field, strings, solitons, anomalies and the speed of life
Niemi, Antti J
2014-01-01T23:59:59.000Z
It's been said that "mathematics is biology's next microscope, only better; biology is mathematics' next physics, only better". Here we aim for something even better. We try to combine mathematical physics and biology into a picoscope of life. For this we merge techniques which have been introduced and developed in modern mathematical physics, largely by Ludvig Faddeev to describe objects such as solitons and Higgs and to explain phenomena such as anomalies in gauge fields. We propose a synthesis that can help to resolve the protein folding problem, one of the most important conundrums in all of science. We apply the concept of gauge invariance to scrutinize the extrinsic geometry of strings in three dimensional space. We evoke general principles of symmetry in combination with Wilsonian universality and derive an essentially unique Landau-Ginzburg energy that describes the dynamics of a generic string-like configuration in the far infrared. We observe that the energy supports topological solitons, that perta...
Aspects of noncommutativity in field theory, strings and membranes
Kuldeep Kumar
2008-12-30T23:59:59.000Z
We study certain aspects of noncommutativity in field theory, strings and membranes. We analyse the dynamics of an open membrane whose boundary is attached to p-branes. Noncommutative features of the boundary string coordinates are revealed by algebraic consistency arguments. Next, we derive Seiberg-Witten-type maps relating currents and their divergences in nonabelian U(N) noncommutative gauge theory with the corresponding expressions in the ordinary (commutative) description. We then exploit these maps to obtain the O(\\theta) structure of the commutator anomalies in noncommutative electrodynamics. Finally, we discuss the issue of violation of Lorentz invariance in noncommutative gauge theories by explicitly deriving, following a Noether-like approach, the criteria for preserving Poincare invariance. We also study general (deformed) conformal-Poincare (Galilean) symmetries consistent with relativistic (nonrelativistic) canonical noncommutative spaces.
Vacuum Polarization on the Schwarzschild Metric with a Cosmic String
Adrian C. Ottewill; Peter Taylor
2010-06-30T23:59:59.000Z
We consider the problem of the renormalization of the vacuum polarization in a symmetry space-time with axial but not spherical symmetry, Schwarzschild space-time threaded by an infinite straight cosmic string. Unlike previous calculations, our framework to compute the renormalized vacuum polarization does not rely on special properties of Legendre functions, but rather has been developed in a way that we expect to be applicable to Kerr space-time.
Phenomenology of heterotic and type II orientifold string models
Mayes, Van Eric
2009-05-15T23:59:59.000Z
. SupersymmetryConditionsintheOpenString Sector . . . . . . . . . . . . . . . . . . . . . . . . 73 5. RR Tadpole Cancellation and K-theory Constraints . 73 6. The Green-Schwarz Mechanism for Flipped SU(5) GUT Construction . . . . . . . . . . . . . . . . . . . . 75...)?SU(2)L?SU(2)R?[U(2)4? U(1)3]. The ?0d representations indicate light, non-chiral matter which is present between pairs of fractional branes which wrap homologically identical bulk cycles, but difier in their twisted cycles. 98 XVI Stacks, wrapping...
Boundary String Field Theory of the DDbar System
Kraus, P; Kraus, Per; Larsen, Finn
2001-01-01T23:59:59.000Z
We develop the boundary string field theory approach to tachyon condensation on the DDbar system. Particular attention is paid to the gauge fields, which combine with the tachyons in a natural way. We derive the RR-couplings of the system and express the result in terms of Quillen's superconnection. The result is related to an index theorem, and is thus shown to be exact.
Effective Supergravity from the Weakly Coupled HeteroticString
Gaillard, Mary K.
2005-05-01T23:59:59.000Z
The motivation for Calabi-Yau-like compactifications of the weakly coupled E{sub 8} {circle_times} E{sub 8} heterotic string theory, its particle spectrum and the issue of dilaton stabilization are briefly reviewed. Modular invariant models for hidden sector condensation and supersymmetry breaking are described at the quantum level of the effective field theory. Their phenomenological and cosmological implications, including a possible origin for R-parity, are discussed.
Stability of false vacuum in supersymmetric theories with cosmic strings
Kumar, Brijesh; Yajnik, Urjit A. [Department of Physics, Indian Institute of Technology, Bombay, Mumbai - 400076 (India)
2009-03-15T23:59:59.000Z
We study the stability of supersymmetry breaking vacuum in the presence of cosmic strings arising in the messenger sector. For certain ranges of the couplings, the desired supersymmetry breaking vacua become unstable against decay into phenomenologically unacceptable vacua. This sets constraints on the range of allowed values of the coupling constants appearing in the models and more generally on the chosen dynamics of gauge symmetry breaking.
Jorda, R.M.
1980-03-01T23:59:59.000Z
The effects of formation characteristics on injection well performance are reviewed. Use of data acquired from cores taken from injection horizons to predict injectivity is described. And methods for utilizing data from bench scale testing of brine and core samples to optimize injection well design are presented. Currently available methods and equipment provide data which enable the optimum design of injection wells through analysis of cores taken from injection zones. These methods also provide a means of identifying and correcting well injection problems. Methods described in this report are: bulk density measurement; porosity measurement; pore size distribution analysis; permeability measurement; formation grain size distribution analysis; core description (lithology) and composition; amount, type and distribution of clays and shales; connate water analysis; consolidatability of friable reservoir rocks; grain and pore characterization by scanning electron microscopy; grain and pore characterization by thin section analysis; permeability damage and enhancement tests; distribution of water-borne particles in porous media; and reservoir matrix acidizing effectiveness. The precise methods of obtaining this information are described, and their use in the engineering of injection wells is illustrated by examples, where applicable. (MHR)
Experiences with string matching on the Fermi Architecture
Tumeo, Antonino; Secchi, Simone; Villa, Oreste
2011-02-25T23:59:59.000Z
String matching is at the core of many real-world applications, such as security, bioinformatic, data mining. All these applications requires the ability to match always growing data sets against large dictionaries effectively, fastly and possibly in real time. Unfortunately, string matching is a computationally intensive procedure which poses significant challenges on current software and hardware implementations. Graphic Processing Units (GPU) have become an interesting target for such high-throughput applications, but the algorithms and the data structures need to be redesigned to be parallelized and adapted to the underlining hardware, coping with the limitations imposed by these architectures. In this paper we present an efficient implementation of the Aho-Corasick string matching algorithm on GPU, showing how we progressively redesigned the algorithm and the data structures to fit on the architecture. We then evaluate the implementation on single and multiple Tesla C2050 (T20 ``Fermi'' based) boards, comparing them to the previous Tesla C1060 (T10 based) solutions and equivalent multicore implementations on x86 CPUs. We discuss the various tradeoffs of the different architectures.
Gauge field, strings, solitons, anomalies and the speed of life
Antti J. Niemi
2014-07-05T23:59:59.000Z
It's been said that "mathematics is biology's next microscope, only better; biology is mathematics' next physics, only better". Here we aim for something even better. We try to combine mathematical physics and biology into a picoscope of life. For this we merge techniques which have been introduced and developed in modern mathematical physics, largely by Ludvig Faddeev to describe objects such as solitons and Higgs and to explain phenomena such as anomalies in gauge fields. We propose a synthesis that can help to resolve the protein folding problem, one of the most important conundrums in all of science. We apply the concept of gauge invariance to scrutinize the extrinsic geometry of strings in three dimensional space. We evoke general principles of symmetry in combination with Wilsonian universality and derive an essentially unique Landau-Ginzburg energy that describes the dynamics of a generic string-like configuration in the far infrared. We observe that the energy supports topological solitons, that pertain to an anomaly in the manner how a string is framed around its inflection points. We explain how the solitons operate as modular building blocks from which folded proteins are composed. We describe crystallographic protein structures by multi-solitons with experimental precision, and investigate the non-equilibrium dynamics of proteins under varying temperature. We simulate the folding process of a protein at in vivo speed and with close to pico-scale accuracy using a standard laptop computer: With pico-biology as mathematical physics' next pursuit, things can only get better.
CERN Winter School on Supergravity, Strings, and Gauge Theory 2010
None
2011-10-06T23:59:59.000Z
The CERN Winter School on Supergravity, Strings, and Gauge Theory is the analytic continuation of the yearly training school of the former EC-RTN string network "Constituents, Fundamental Forces and Symmetries of the Universe". The 2010 edition of the school is supported and organized by the CERN Theory Divison, and will take place from Monday January 25 to Friday January 29, at CERN. As its predecessors, this school is meant primarily for training of doctoral students and young postdoctoral researchers in recent developments in theoretical high-energy physics and string theory. The programme of the school will consist of five series of pedagogical lectures, complemented by tutorial discussion sessions in the afternoons. Previous schools in this series were organized in 2005 at SISSA in Trieste, and in 2006, 2007, 2008, and 2009 at CERN, Geneva. Other similar schools have been organized in the past by the former related RTN network "The Quantum Structure of Spacetime and the Geometric Nature of Fundamental Interactions". This edition of the school is not funded by the European Union. The school is funded by the CERN Theory Division, and the Arnold Sommerfeld Center at Ludwig-Maximilians University of Munich. Scientific committee: M. Gaberdiel, D. Luest, A. Sevrin, J. Simon, K. Stelle, S. Theisen, A. Uranga, A. Van Proeyen, E. Verlinde Local organizers: A. Uranga, J. Walcher
Dangerous Angular KK/Glueball Relics in String Theory Cosmology
J. F. Dufaux; L. Kofman; M. Peloso
2008-07-07T23:59:59.000Z
The presence of Kaluza-Klein particles in the universe is a potential manifestation of string theory cosmology. In general, they can be present in the high temperature bath of the early universe. In particular examples, string theory inflation often ends with brane-antibrane annihilation followed by the energy cascading through massive closed string loops to KK modes which then decay into lighter standard model particles. However, massive KK modes in the early universe may become dangerous cosmological relics if the inner manifold contains warped throat(s) with approximate isometries. In the complimentary picture, in the AdS/CFT dual gauge theory with extra symmetries, massive glueballs of various spins become the dangerous cosmological relics. The decay of these angular KK modes/glueballs, located around the tip of the throat, is caused by isometry breaking which results from gluing the throat to the compact CY manifold. We address the problem of these angular KK particles/glueballs, studying their interactions and decay channels, from the theory side, and the resulting cosmological constraints on the warped compactification parameters, from the phenomenology side. The abundance and decay time of the long-lived non-relativistic angular KK modes depend strongly on the parameters of the warped geometry, so that observational constraints rule out a significant fraction of the parameter space. In particular, the coupling of the angular KK particles can be weaker than gravitational.
Anomaly of Tensionless String in Light-cone Gauge
Kenta Murase
2015-03-04T23:59:59.000Z
The classical tensionless string theory has the spacetime conformal symmetry. We expect and require that the quantum tensionless string theory has it too. In the BRST quantization method, the theory has no spacetime conformal anomaly in two dimensions. On the other hand, in the light-cone gauge quantization without the mode expansion, the theory in $D>3$ has the spacetime conformal anomaly in the traceless part of $[\\mathcal{J}^{-I}, \\mathcal{K}^{J}]$ in some operator order. In this paper, we consider a tensionless closed bosonic string in the light-cone gauge and investigate the spacetime conformal anomaly in the theory with the mode expansion. The appearance of the spacetime conformal anomaly in the light-cone gauge is different between the case of $D>3$ and the case of $D=3$ and depends on the choice of the operator order. Therefore we must consider dangerous commutators in the spacetime conformal symmetry of $D>3$ and $D=3$ in each operator order separately. Specifically we calculate dangerous commutators, $[\\mathcal{J}^{-I},\\mathcal{K}^{K}]$ in $D>3$ and $\\tilde{\\mathcal{K}}^{-}\\equiv -i[\\mathcal{J}^{-}, \\tilde{\\mathcal{K}}^{-}]$ and $[\\mathcal{J}^{-}, \\tilde{\\mathcal{K}}^{-}]$ in $D=3$, in two types of the operator order.
Anomaly of Tensionless String in Light-cone Gauge
Murase, Kenta
2015-01-01T23:59:59.000Z
The classical tensionless string theory has the spacetime conformal symmetry. We expect and require that the quantum tensionless string theory has it too. In the BRST quantization method, the theory has no spacetime conformal anomaly in two dimensions. On the other hand, in the light-cone gauge quantization without the mode expansion, the theory in $D>3$ has the spacetime conformal anomaly in the traceless part of $[\\mathcal{J}^{-I}, \\mathcal{K}^{J}]$ in some operator order. In this paper, we consider a tensionless closed bosonic string in the light-cone gauge and investigate the spacetime conformal anomaly in the theory with the mode expansion. The appearance of the spacetime conformal anomaly in the light-cone gauge is different between the case of $D>3$ and the case of $D=3$ and depends on the choice of the operator order. Therefore we must consider dangerous commutators in the spacetime conformal symmetry of $D>3$ and $D=3$ in each operator order separately. Specifically we calculate dangerous commutators...
Spiky strings and giant magnons on S5
M. Kruczenski; J. Russo; A. A. Tseytlin
2006-07-14T23:59:59.000Z
Recently, classical solutions for strings moving in AdS5 x S5 have played an important role in understanding the AdS/CFT correspondence. A large set of them were shown to follow from an ansatz that reduces the solution of the string equations of motion to the study of a well-known integrable 1-d system known as the Neumann-Rosochatius (NR) system. However, other simple solutions such as spiky strings or giant magnons in S5 were not included in the NR ansatz. We show that, when considered in the conformal gauge, these solutions can be also accomodated by a version of the NR-system. This allows us to describe in detail a giant magnon solution with two additional angular momenta and show that it can be interpreted as a superposition of two magnons moving with the same speed. In addition, we consider the spin chain side and describe the corresponding state as that of two bound states in the infinite SU(3) spin chain. We construct the Bethe ansatz wave function for such bound state.
Interpolating the Coulomb Phase of Little String Theory
Ying-Hsuan Lin; Shu-Heng Shao; Yifan Wang; Xi Yin
2015-02-05T23:59:59.000Z
We study up to 8-derivative terms in the Coulomb branch effective action of (1,1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity on the Coulomb branch, numerically from SU(k) SYM and DSLST respectively, for k=2,3,4,5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. We also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2,0) little string theory.
Field Definitions, Spectrum and Universality in Effective String Theories
N. D. Hari Dass; Peter Matlock
2006-12-28T23:59:59.000Z
It is shown, by explicit calculation, that the third-order terms in inverse string length in the spectrum of the effective string theories of Polchinski and Strominger are also the same as in Nambu-Goto theory, in addition to the universal Luescher terms. While the Nambu-Goto theory is inconsistent outside the critical dimension, the Polchinski-Strominger theory is by construction consistent for any space-time dimension. In the analysis of the spectrum, care is taken not to use any field redefinition, as it is felt that this has the potential to obscure important points. Nevertheless, as field redefinition is an important tool and the definition of the field should be made precise, a careful analysis of the choice of field definition leading to the terms in the action is also presented. Further, it is shown how a choice of field definition can be made in a systematic way at higher orders. To this end the transformation of measure involved is calculated, in the context of effective string theory, and thereby a quantum evaluation made of equivalence of theories related by a field redefinition. It is found that there are interesting possibilities resulting from a redefinition of fluctuation field.
Conformal Transformations and Strings for an Accelerating Quark-Antiquark Pair in AdS3
Shijong Ryang
2014-12-08T23:59:59.000Z
From a simple moving open string solution dual to a moving heavy quark with constant velocity in the Poincare AdS_3 spacetime, we construct an accerlerating open string solution dual to a heavy quark-antiquark pair accelerated in opposite directions by performing the three mappings such as the SL(2,R)_L x SL(2,R)_R isometry transformation, the special conformal transformation and the conformal SO(2,2) transformation. Using the string sigma model action we construct two open string solutions staying in two different regions whose dividing line is associated with the event horizon appeared on the string worldsheet and obtain the accelerating open string solution by gluing two such solutions.
Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors
J. Aasi; J. Abadie; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; T. Accadia; F. Acernese; C. Adams; T. Adams; R. X. Adhikari; C. Affeldt; M. Agathos; N. Aggarwal; O. D. Aguiar; P. Ajith; B. Allen; A. Allocca; E. Amador Ceron; D. Amariutei; R. A. Anderson; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. Areeda; S. Ast; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; L. Austin; B. E. Aylott; S. Babak; P. T. Baker; G. Ballardin; S. W. Ballmer; J. C. Barayoga; D. Barker; S. H. Barnum; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. Batch; J. Bauchrowitz; Th. S. Bauer; M. Bebronne; B. Behnke; M. Bejger; M. G. Beker; A. S. Bell; C. Bell; I. Belopolski; G. Bergmann; J. M. Berliner; D. Bersanetti; A. Bertolini; D. Bessis; J. Betzwieser; P. T. Beyersdorf; T. Bhadbhade; I. A. Bilenko; G. Billingsley; J. Birch; M. Bitossi; M. A. Bizouard; E. Black; J. K. Blackburn; L. Blackburn; D. Blair; M. Blom; O. Bock; T. P. Bodiya; M. Boer; C. Bogan; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; V. Boschi; S. Bose; L. Bosi; J. Bowers; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; C. A. Brannen; J. E. Brau; J. Breyer; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; M. Britzger; A. F. Brooks; D. A. Brown; D. D. Brown; F. Brückner; T. Bulik; H. J. Bulten; A. Buonanno; D. Buskulic; C. Buy; R. L. Byer; L. Cadonati; G. Cagnoli; J. Calderón Bustillo; E. Calloni; J. B. Camp; P. Campsie; K. C. Cannon; B. Canuel; J. Cao; C. D. Capano; F. Carbognani; L. Carbone; S. Caride; A. Castiglia; S. Caudill; M. Cavagliá; F. Cavalier; R. Cavalieri; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. Chao; P. Charlton; E. Chassande-Mottin; X. Chen; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; J. Chow; N. Christensen; Q. Chu; S. S. Y. Chua; S. Chung; G. Ciani; F. Clara; D. E. Clark; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; M. Colombini; M. Constancio Jr.; A. Conte; R. Conte; D. Cook; T. R. Corbitt; M. Cordier; N. Cornish; A. Corsi; C. A. Costa; M. W. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. Cowart; D. C. Coyne; K. Craig; J. D. E. Creighton; T. D. Creighton; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; V. Dattilo; B. Daudert; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; T. Dayanga; R. De Rosa; G. Debreczeni; J. Degallaix; W. Del Pozzo; E. Deleeuw; S. Deléglise; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. DeRosa; R. DeSalvo; S. Dhurandhar; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; M. Díaz; A. Dietz; K. Dmitry; F. Donovan; K. L. Dooley; S. Doravari; M. Drago; R. W. P. Drever; J. C. Driggers; Z. Du; J. -C. Dumas; S. Dwyer; T. Eberle; M. Edwards; A. Effler; P. Ehrens; J. Eichholz; S. S. Eikenberry; G. Endröczi; R. Essick; T. Etzel; K. Evans; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; Q. Fang; S. Farinon; B. Farr; W. Farr; M. Favata; D. Fazi; H. Fehrmann; D. Feldbaum; I. Ferrante; F. Ferrini; F. Fidecaro; L. S. Finn; I. Fiori; R. Fisher; R. Flaminio; E. Foley; S. Foley; E. Forsi; N. Fotopoulos; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; M. Frede; M. Frei; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; M. -K. Fujimoto; P. Fulda; M. Fyffe; J. Gair; L. Gammaitoni; J. Garcia; F. Garufi; N. Gehrels; G. Gemme; E. Genin; A. Gennai; L. Gergely; S. Ghosh; J. A. Giaime; S. Giampanis; K. D. Giardina; A. Giazotto; S. Gil-Casanova; C. Gill; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. González; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goßler; R. Gouaty; C. Graef; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; C. Griffo; P. Groot; H. Grote; K. Grover; S. Grunewald; G. M. Guidi; C. Guido; K. E. Gushwa; E. K. Gustafson; R. Gustafson; B. Hall; E. Hall; D. Hammer; G. Hammond; M. Hanke; J. Hanks; C. Hanna; J. Hanson; J. Harms; G. M. Harry; I. W. Harry; E. D. Harstad; M. T. Hartman; K. Haughian; K. Hayama; J. Heefner; A. Heidmann; M. Heintze; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; S. Hild; D. Hoak; K. A. Hodge; K. Holt; M. Holtrop; T. Hong; S. Hooper; T. Horrom; D. J. Hosken; J. Hough; E. J. Howell; Y. Hu; Z. Hua; V. Huang; E. A. Huerta; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; J. Iafrate; D. R. Ingram; R. Inta; T. Isogai; A. Ivanov; B. R. Iyer; K. Izumi; M. Jacobson; E. James; H. Jang; Y. J. Jang; P. Jaranowski; F. Jiménez-Forteza; W. W. Johnson; D. Jones; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; P. Kalmus; V. Kalogera; S. Kandhasamy; G. Kang; J. B. Kanner; M. Kasprzack; R. Kasturi; E. Katsavounidis; W. Katzman; H. Kaufer; K. Kaufman; K. Kawabe; S. Kawamura; F. Kawazoe
2014-04-07T23:59:59.000Z
Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension $G\\mu$ below $10^{-8}$ in some regions of the cosmic string parameter space.
Resonant acoustic transducer and driver system for a well drilling string communication system
Chanson, Gary J. (Weston, MA); Nicolson, Alexander M. (Concord, MA)
1981-01-01T23:59:59.000Z
The acoustic data communication system includes an acoustic transmitter and receiver wherein low frequency acoustic waves, propagating in relatively loss free manner in well drilling string piping, are efficiently coupled to the drill string and propagate at levels competitive with the levels of noise generated by drilling machinery also present in the drill string. The transmitting transducer incorporates a mass-spring piezoelectric transmitter and amplifier combination that permits self-oscillating resonant operation in the desired low frequency range.
On Rotating and Oscillating Four-Spin Strings in AdS5 X S5
Kamal L. Panigrahi; Pabitra M. Pradhan
2012-10-26T23:59:59.000Z
We study rigidly rotating strings in AdS5 X S5 background with one spin along AdS5 and three angular momenta along S5. We find dispersion relations among various charges and interpret them as giant magnon and spiky string solutions in various limits. Further we present an example of oscillating string which oscillates in the radial direction of the AdS5 and at the same time rotates in S5.
On Rotating and Oscillating Four-Spin Strings in AdS5 X S5
Panigrahi, Kamal L
2012-01-01T23:59:59.000Z
We study rigidly rotating strings in AdS5 X S5 background with one spin along AdS5 and three angular momenta along S5. We find dispersion relations among various charges and interpret them as giant magnon and spiky string solutions in various limits. Further we present an example of oscillating string which oscillates in the radial direction of the AdS5 and at the same time rotates in S5.
Lectures on D-branes, tachyon condensation, and string field theory
Washington Taylor
2003-01-15T23:59:59.000Z
These lectures provide an introduction to the subject of tachyon condensation in the open bosonic string. The problem of tachyon condensation is first described in the context of the low-energy Yang-Mills description of a system of multiple D-branes, and then using the language of string field theory. An introduction is given to Witten's cubic open bosonic string field theory. The Sen conjectures on tachyon condensation in open bosonic string field theory are introduced, and evidence confirming these conjectures is reviewed.
U-092: Sudo Format String Bug Lets Local Users Gain Elevated Privileges
Broader source: Energy.gov [DOE]
A local user can supply a specially crafted command line argument to trigger a format string flaw and execute arbitrary commands on the target system with root privileges.
Report on ignitability testing of flammable gasses in a core sampling drill string
Witwer, K.S., Westinghouse Hanford
1996-12-01T23:59:59.000Z
This document describes the results from testing performed at the Pittsburgh Research Center to determine the effects of an ignition of flammable gasses contained in a core sampling drill string. Testing showed that 1) An ignition of stoichiometric hydrogen and air in a vented 30 or 55 ft length of drill string will not force 28`` or more of water out the bottom of the drill string, and 2) An ignition of this same gas mixture will not rupture a vented or completely sealed drill string.
B polarization of the cosmic microwave background as a tracer of strings
Seljak, Uros [Department of Physics, Princeton University, Princeton New Jersey 08544 (United States); International Center for Theoretical Physics, Trieste (Italy); Slosar, Anze [Faculty of Mathematics and Physics, University of Ljubljana (Slovenia)
2006-09-15T23:59:59.000Z
String models can produce successful inflationary scenarios in the context of brane collisions, and in many of these models cosmic strings may also be produced. In scenarios such as Kachru-Kallosh-Linde-Maldacena-McAllister-Trivedi (KKLMMT) scenario the string contribution is naturally predicted to be well below the inflationary signal for cosmic microwave background (CMB) temperature anisotropies, in agreement with the existing limits. We find that for B type polarization of CMB the situation is reversed and the dominant signal comes from vector modes generated by cosmic strings, which exceeds the gravity wave signal from both inflation and strings. The signal can be detected for a broad range of parameter space; future polarization experiments may be able to detect the string signal down to the string tension G{mu}=10{sup -9}, although foregrounds and lensing are likely to worsen these limits. We argue that the optimal scale to search for the string signature is at l{approx}1000, but in models with high optical depth the signal from reionization peak at large scales is also significant. The shape of the power spectrum allows one to distinguish the string signature from the gravity waves from inflation, but only with a sufficiently high angular resolution experiment.
Shyamoli Chaudhuri
2005-09-06T23:59:59.000Z
We give a first principles formulation of the equilibrium statistical mechanics of strings in the canonical ensemble, compatible with the Euclidean timelike T-duality transformations that link the six supersymmetric string theories in pairs. We demonstrate that each exhibits a T^2 growth in the free energy at high temperatures far above the string scale. We verify that the low energy field theory limit of our expression for the string free energy reproduces the expected T^{10} growth when the contribution from massive string modes is suppressed. In every case, heterotic, type I, and type II, we can definitively rule out the occurrence of an exponential divergence in the one-loop string free energy above some critical temperature. Finally, we identify a macroscopic loop amplitude in the type I string theories which yields the expectation value of a single Wilson-Polyakov-Susskind loop in the low energy finite temperature supersymmetric gauge theory limit, an order parameter for a thermal phase transition at a string scale temperature. We point out that precise computations can nevertheless be carried out on either side of the phase boundary by using the low energy finite temperature supersymmetric gauge theory limits of the pair of thermal dual string theories, type IB and type I'. Note Added (Sep 2005).
{gamma}-Radiolysis of NaCl Brine in the Presence of UO{sub 2}(s): Effects of Hydrogen and Bromide
Metz, Volker; Bohnert, Elke; Kelm, Manfred; Schild, Dieter; Kienzler, Bernhard [Institute for Radioactive Waste Disposal (FZK-INE), Forschungszentrum Karlsruhe / Research Center Karlsruhe, Helmholtz-Platz, Eggenstein-Leopoldshafen, D-76344 (Germany); Reinhardt, Juergen; Buchmeiser, Michael R. [Leibniz-Institut fuer Oberflaechenmodifizierung, IOM, Permoserstr. 15, Leipzig, D-04318 (Germany)
2007-07-01T23:59:59.000Z
A concentrated NaCl solution was {gamma}-irradiated in autoclaves under a pressure of 25 MPa. A set of experiments were conducted in 6 mol (kg H{sub 2}O){sup -1} NaCl solution in the presence of UO{sub 2}(s) pellets; in a second set of experiments, {gamma}-radiolysis of the NaCl brine was studied without UO{sub 2}(s). Hydrogen, oxygen and chlorate were formed as long-lived radiolysis products. Due to the high external pressure, all radiolysis products remained dissolved. H{sub 2} and O{sub 2} reached steady state concentrations in the range of 5.10{sup -3} to 6.10{sup -2} mol (kg H{sub 2}O){sup -1} corresponding to a partial gas pressure of {approx}2 to {approx}20 MPa. Radiolytic formation of hydrogen and oxygen increased with the concentration of bromide added to solution. Both, in the presence of bromide, resulting in a relatively high radiolytic yield, and in the absence of bromide surfaces of the UO{sub 2}(s) samples were oxidized, and concentration of dissolved uranium reached the solubility limit of the schoepite / NaUO{sub 2}O(OH)(cr) transition. At the end of the experiments, the pellets were covered by a surface layer of a secondary solid phase having a composition close to Na{sub 2}U{sub 2}O{sub 7}. The experimental results demonstrate that bromide counteracts an H{sub 2} inhibition effect on radiolysis gas production, even at a concentration ratio of [H{sub 2}] / [Br{sup -}] > 100. The present observations are related to the competitive reactions of OH radicals with H{sub 2}, Br{sup -} and Cl{sup -}. A similar competition of hydrogen and bromide, controlling the yield of {gamma}-radiolysis products, is expected for solutions of lower Cl{sup -} concentration. (authors)
Efficient Aho-Corasick String Matching on Emerging Multicore Architectures
Tumeo, Antonino; Villa, Oreste; Secchi, Simone; Chavarría-Miranda, Daniel
2013-12-12T23:59:59.000Z
String matching algorithms are critical to several scientific fields. Beside text processing and databases, emerging applications such as DNA protein sequence analysis, data mining, information security software, antivirus, ma- chine learning, all exploit string matching algorithms [3]. All these applica- tions usually process large quantity of textual data, require high performance and/or predictable execution times. Among all the string matching algorithms, one of the most studied, especially for text processing and security applica- tions, is the Aho-Corasick algorithm. 1 2 Book title goes here Aho-Corasick is an exact, multi-pattern string matching algorithm which performs the search in a time linearly proportional to the length of the input text independently from pattern set size. However, depending on the imple- mentation, when the number of patterns increase, the memory occupation may raise drastically. In turn, this can lead to significant variability in the performance, due to the memory access times and the caching effects. This is a significant concern for many mission critical applications and modern high performance architectures. For example, security applications such as Network Intrusion Detection Systems (NIDS), must be able to scan network traffic against very large dictionaries in real time. Modern Ethernet links reach up to 10 Gbps, and malicious threats are already well over 1 million, and expo- nentially growing [28]. When performing the search, a NIDS should not slow down the network, or let network packets pass unchecked. Nevertheless, on the current state-of-the-art cache based processors, there may be a large per- formance variability when dealing with big dictionaries and inputs that have different frequencies of matching patterns. In particular, when few patterns are matched and they are all in the cache, the procedure is fast. Instead, when they are not in the cache, often because many patterns are matched and the caches are continuously thrashed, they should be retrieved from the system memory and the procedure is slowed down by the increased latency. Efficient implementations of string matching algorithms have been the fo- cus of several works, targeting Field Programmable Gate Arrays [4, 25, 15, 5], highly multi-threaded solutions like the Cray XMT [34], multicore proces- sors [19] or heterogeneous processors like the Cell Broadband Engine [35, 22]. Recently, several researchers have also started to investigate the use Graphic Processing Units (GPUs) for string matching algorithms in security applica- tions [20, 10, 32, 33]. Most of these approaches mainly focus on reaching high peak performance, or try to optimize the memory occupation, rather than looking at performance stability. However, hardware solutions supports only small dictionary sizes due to lack of memory and are difficult to customize, while platforms such as the Cell/B.E. are very complex to program.
Self-Gravitating Non-Abelian Cosmic String Solution
Reinoud J. Slagter
1998-09-15T23:59:59.000Z
The coupled Einstein-Yang-Mills equations on a time dependent axially symmetric spacetime are investigated, without a priori any conditions on the gauge field. There is numerical evidence for the existence of a regular solution with the desired asymptotic features. Just as in the supermassive abelian counterpart model, the formation of a singularity at finite distance of the core of the string depends critically on a parameter of the model, i.e., the constant value of one of the magnetic components of the YM potentials. The multiple-scale method could supply decisive answers concerning the stability of the solution.
Exact results on ABJ theory and the refined topological string
Masazumi Honda; Kazumi Okuyama
2014-07-22T23:59:59.000Z
We study the partition function of the ABJ theory, which is the N=6 superconformal Chern-Simons matter theory with gauge group U(N)xU(N+M) and Chern-Simons levels (k,-k). We exactly compute the ABJ partition function on a three sphere for various k, M and N via the Fermi gas approach. By using these exact data, we show that the ABJ partition function is completely determined by the refined topological string on local P^1 x P^1, including membrane instanton effects in the M-theory dual.
System and method for damping vibration in a drill string
Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E; Perry, Carl Allison
2014-03-04T23:59:59.000Z
A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
Turing's Landscape: decidability, computability and complexity in string theory
Abhijnan Rej
2009-09-10T23:59:59.000Z
I argue that questions of algorithmic decidability, computability and complexity should play a larger role in deciding the "ultimate" theoretical description of the Landscape of string vacua. More specifically, I examine the notion of the average rank of the (unification) gauge group in the Landscape, the explicit construction of Ricci-flat metrics on Calabi-Yau manifolds as well as the computability of fundamental periods to show that undecidability questions are far more pervasive than that described in the work of Denef and Douglas.
System and method for damping vibration in a drill string
Wassell, Mark Ellsworth (Kingwood, TX); Turner, William Evans (Durham, CT); Burgess, Daniel E. (Middletown, CT); Perry, Carl Allison (Middletown, CT)
2011-08-16T23:59:59.000Z
A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
System and method for damping vibration in a drill string
Wassell, Mark Ellsworth (Kingswood, TX); Turner, William Evans (Durham, CT); Burgess, Daniel E. (Middletown, CT); Perry, Carl Allison (Middletown, CT)
2012-08-14T23:59:59.000Z
A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
System and method for damping vibration in a drill string
Wassell, Mark Ellsworth (Kingwood, TX); Turner, William Evans (Durham, CT); Burgess, Daniel E. (Middletown, CT); Perry, Carl Allison (Middletown, CT)
2008-05-27T23:59:59.000Z
A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
System and method for damping vibration in a drill string
Wassell, Mark Ellsworth (Kingwood, TX); Turner, William Evans (Durham, CT); Burgess, Daniel E. (Middletown, CT); Perry, Carl Allison (Middletown, CT)
2007-05-22T23:59:59.000Z
A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
Nonlocal String Tachyon as a Model for Cosmological Dark Energy
Aref'eva, Irina Ya. [Steklov Mathematical Institute, Russian Academy of Sciences, Gubkin st. 8, Moscow, 119991 (Russian Federation)
2006-03-29T23:59:59.000Z
There are many different phenomenological models describing the cosmological dark energy and accelerating Universe by choosing adjustable functions. In this paper we consider a specific model of scalar tachyon field which is derived from the NSR string field theory and study its cosmological applications. We find that in the effective field theory approximation the equation of state parameter w < -1, i.e. one has a phantom Universe. It is shown that due to nonlocal effects there is no quantum instability that the usual phantom models suffer from. Moreover due to a flip effect of the potential the Universe does not enter to a future singularity.
Open string moduli in Kachru-Kallosh-Linde-Trivedi compactifications
Aharony, Ofer; Antebi, Yaron E.; Berkooz, Micha [Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100 (Israel)
2005-11-15T23:59:59.000Z
In the Kachru-Kallosh-Linde-Trivedi (KKLT) de-Sitter construction one introduces an anti-D3-brane that breaks the supersymmetry and leads to a positive cosmological constant. In this paper we investigate the open string moduli associated with this anti-D3-brane, corresponding to its position on the S{sup 3} at the tip of the deformed conifold. We show that in the KKLT construction these moduli are very light, and we suggest a possible way to give these moduli a large mass by putting orientifold planes in the KKLT ''throat.''.
String black hole: Can it be a particle accelerator ?
Sharmanthie Fernando
2014-08-21T23:59:59.000Z
In this paper we have studied the possibility of the center-of-mass energy of two particles colliding near the horizon of a static charged black hole in string theory. Various cases corresponding to the electric charge and the angular momentum of the particles were considered. The studies were done for the general black hole as well as for the extreme black hole. There were two scenarios where the center-of-mass energy reach very large values if the appropriate properties of the particles are chosen.
Size scaling of self gravitating polymers and strings
Kawamoto, Shoichi
2015-01-01T23:59:59.000Z
We study a statistical ensemble of a single polymer with self gravitational interaction. This is a model of a gravitating string --- the precursor of a black hole. We analyze averaged sizes by mean field approximations with an effective Hamiltonian a la Edwards with Newtonian potential as well as a contact repulsive interaction. We find that there exists a certain scaling region where the attractive and the repulsive forces balance out. The repulsive interaction pushes the critical gravitational coupling to a larger value, at which the size of a polymer becomes comparable to its Schwarzschild radius, and as a result the size of the corresponding black hole increases considerably.
Size scaling of self gravitating polymers and strings
Shoichi Kawamoto; Toshihiro Matsuo
2015-06-03T23:59:59.000Z
We study a statistical ensemble of a single polymer with self gravitational interaction. This is a model of a gravitating string --- the precursor of a black hole. We analyze averaged sizes by mean field approximations with an effective Hamiltonian a la Edwards with Newtonian potential as well as a contact repulsive interaction. We find that there exists a certain scaling region where the attractive and the repulsive forces balance out. The repulsive interaction pushes the critical gravitational coupling to a larger value, at which the size of a polymer becomes comparable to its Schwarzschild radius, and as a result the size of the corresponding black hole increases considerably.
CMB distortions from damping of acoustic waves produced by cosmic strings
Tashiro, Hiroyuki; Sabancilar, Eray; Vachaspati, Tanmay, E-mail: Hiroyuki.Tashiro@asu.edu, E-mail: Eray.Sabancilar@asu.edu, E-mail: tvachasp@asu.edu [Physics Department, Arizona State University, Tempe, Arizona 85287 (United States)
2013-08-01T23:59:59.000Z
We study diffusion damping of acoustic waves in the photon-baryon fluid due to cosmic strings, and calculate the induced ?- and y-type spectral distortions of the cosmic microwave background. For cosmic strings with tension within current bounds, their contribution to the spectral distortions is subdominant compared to the distortions from primordial density perturbations.
The anomaly-free quantization of two-dimensional relativistic string. I
S. N. Vergeles
1998-12-21T23:59:59.000Z
An anomaly-free quantum theory of a relativistic string is constructed in two-dimensional space-time. The states of the string are found to be similar to the states of a massless chiral quantum particle. This result is obtained by generalizing the concept of an ``operator'' in quantum field theory.
DRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto
Boyer, Edmond
DRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto R. Sampaio thiagoritto Descartes, 77454 Marne-la-VallÃ©e, France Abstract. The influence of the drilling fluid (or mud) on the drill in the analysis of the nonlinear dynamics of a drill-string. The aim of this paper is to investigate how the fluid
Wavelet domain Bayesian denoising of string signal in the cosmic microwave background
D. K. Hammond; Y. Wiaux; P. Vandergheynst
2009-04-27T23:59:59.000Z
An algorithm is proposed for denoising the signal induced by cosmic strings in the cosmic microwave background (CMB). A Bayesian approach is taken, based on modeling the string signal in the wavelet domain with generalized Gaussian distributions. Good performance of the algorithm is demonstrated by simulated experiments at arcminute resolution under noise conditions including primary and secondary CMB anisotropies, as well as instrumental noise.
Physics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String
California at Santa Cruz, University of
, Vibrations and Waves (W.W. Norton and Company, New York, 1971). First, we compute the kinetic energyPhysics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String Consider the kinetic energy and the potential energy of this string segment due to the passage of a traveling wave
Kalb-Ramond axion production in anisotropic string cosmologies Ruth Durrer1
Durrer, Ruth
Kalb-Ramond axion production in anisotropic string cosmologies Ruth Durrer1 and Mairi Sakellariadou the energy spectra for massless Kalb-Ramond axions in four-dimensional anisotropic string cosmological models). In contrast, the axion energy spectra were found to be diverging at large scales, red spectra, leading to very
An Efficient Index Structure for String Databases Tamer Kahveci Ambuj K. Singh
Kahveci, Tamer
are genetic data, web data, and event se- quences. Since the size of such databases grows exponentially online access and search capabilities. String data applications generally involve very large databasesAn Efficient Index Structure for String Databases Tamer Kahveci Ambuj K. Singh Department
Fractal Properties and Small-scale Structure of Cosmic String Networks
C. J. A. P. Martins; E. P. S. Shellard
2005-11-29T23:59:59.000Z
We present results from a detailed numerical study of the small-scale and loop production properties of cosmic string networks, based on the largest and highest resolution string simulations to date. We investigate the non-trivial fractal properties of cosmic strings, in particular, the fractal dimension and renormalised string mass per unit length, and we also study velocity correlations. We demonstrate important differences between string networks in flat (Minkowski) spacetime and the two very similar expanding cases. For high resolution matter era network simulations, we provide strong evidence that small-scale structure has converged to `scaling' on all dynamical lengthscales, without the need for other radiative damping mechanisms. We also discuss preliminary evidence that the dominant loop production size is also approaching scaling.
String-theoretic breakdown of effective field theory near black hole horizons
Dodelson, Matthew
2015-01-01T23:59:59.000Z
We investigate the validity of the equivalence principle near horizons in string theory, analyzing the breakdown of effective field theory caused by longitudinal string spreading effects. An experiment is set up where a detector is thrown into a black hole a long time after an early infalling string. Light cone gauge calculations, taken at face value, indicate a detectable level of root-mean-square longitudinal spreading of the initial string as measured by the late infaller. This results from the large relative boost between the string and detector in the near horizon region, which develops automatically despite their modest initial energies outside the black hole and the weak curvature in the geometry. We subject this scenario to basic consistency checks, using these to obtain a relatively conservative criterion for its detectability. In a companion paper, we exhibit longitudinal nonlocality in well-defined gauge-invariant S-matrix calculations, obtaining results consistent with the predicted spreading albe...
String Theory clues for the low-$\\ell$ CMB ?
Kitazawa, N
2014-01-01T23:59:59.000Z
"Brane Supersymmetry Breaking" is a peculiar string-scale mechanism that can unpair Bose and Fermi excitations in orientifold models. It results from the simultaneous presence, in the vacuum, of collections of D-branes and orientifolds that are not mutually BPS, and is closely tied to the scale of string excitations. It also leaves behind, for a mixing of dilaton and internal breathing mode, an exponential potential that is just too steep for a scalar to emerge from the initial singularity while descending it. As a result, in this class of models the scalar can generically bounce off the exponential wall, and this dynamics brings along, in the power spectrum, an infrared depression typically followed by a pre-inflationary peak. We elaborate on a possible link between this type of bounce and the low-$\\ell$ end of the CMB angular power spectrum. For the first 32 multipoles, one can reach a 50 % reduction in $\\chi^{\\,2}$ with respect to the standard $\\Lambda$CDM setting.
Gauge/String-Gravity Duality and Froissart Bound
Kyungsik Kang
2004-10-16T23:59:59.000Z
The gauge/string-gravity duality correspondence opened renewed hope and possibility to address some of the fundamental and non-perturbative QCD problems in particle physics, such as hadron spectrum and Regge behavior of the scattering amplitude at high energies. One of the most fundamental and long-standing problem is the high energy behavior of total cross-sections. According to a series of exhaustive tests by the COMPETE group, (1). total cross-sections have a universal Heisenberg behavior in energy corresponding to the maximal energy behavior allowed by the Froissart bound, i.e., $A + B ln^2 (s/s_0)$ with $B \\sim 0.32 mb$ and $s_0 \\sim 34.41 GeV^2$ for all reactions, and (2). the factorization relation among $\\sigma_{pp, even}, \\sigma_{\\gamma p}, and \\sigma_{\\gamma \\gamma}$ is well satisfied by experiments. I discuss the recent interesting application of the gauge/string-gravity duality of $AdS/CFT$ correspondence with a deformed background metric so as to break the conformal symmetry that can lead to the Heisenberg behavior of rising total cross-sections, and present some preliminary results on the high energy QCD from Planckian scattering in $AdS$ and black-hole production.
A keV String Axion from High Scale Supersymmetry
Brian Henning; John Kehayias; Hitoshi Murayama; David Pinner; Tsutomu T. Yanagida
2015-03-20T23:59:59.000Z
Various theoretical and experimental considerations motivate models with high scale supersymmetry breaking. While such models may be difficult to test in colliders, we propose looking for signatures at much lower energies. We show that a keV line in the X-ray spectrum of galaxy clusters (such as the recently disputed 3.5 keV observation) can have its origin in a universal string axion coupled to a hidden supersymmetry breaking sector. A linear combination of the string axion and an additional axion in the hidden sector remains light, obtaining a mass of order 10 keV through supersymmetry breaking dynamics. In order to explain the X-ray line, the scale of supersymmetry breaking must be about $10^{11-12}$ GeV. This motivates high scale supersymmetry as in pure gravity mediation or minimal split supersymmetry and is consistent with all current limits. Since the axion mass is controlled by a dynamical mass scale, this mass can be much higher during inflation, avoiding isocurvature (and domain wall) problems associated with high scale inflation. In an appendix we present a mechanism for dilaton stabilization that additionally leads to $\\mathcal{O}(1)$ modifications of the gaugino mass from anomaly mediation.
Stable Non-Supersymmetric Throats in String Theory
Kachru, Shamit; Simic, Dusan; /Stanford U., ITP /SLAC /Santa Barbara, KITP; Trivedi, Sandip P.; /Tata Inst. /Stanford U., ITP /SLAC
2011-06-28T23:59:59.000Z
We construct a large class of non-supersymmetric AdS-like throat geometries in string theory by taking non-supersymmetric orbifolds of supersymmetric backgrounds. The scale of SUSY breaking is the AdS radius, and the dual field theory has explicitly broken supersymmetry. The large hierarchy of energy scales in these geometries is stable. We establish this by showing that the dual gauge theories do not have any relevant operators which are singlets under the global symmetries. When the geometries are embedded in a compact internal space, a large enough discrete subgroup of the global symmetries can still survive to prevent any singlet relevant operators from arising. We illustrate this by embedding one case in a non-supersymmetric orbifold of a Calabi-Yau manifold. These examples can serve as a starting point for obtaining Randall-Sundrum models in string theory, and more generally for constructing composite Higgs or technicolor-like models where strongly coupled dynamics leads to the breaking of electro-weak symmetry. Towards the end of the paper, we briefly discuss how bulk gauge fields can be incorporated by introducing D7-branes in the bulk, and also show how the strongly coupled dynamics can lead to an emergent weakly coupled gauge theory in the IR with matter fields including scalars.
Electron string ion sources for carbon ion cancer therapy accelerators
Boytsov, A Yu; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B
2015-01-01T23:59:59.000Z
The Electron String type of Ion Sources (ESIS) was developed, constructed and tested first in the Joint Institute for Nuclear Research. These ion sources can be the appropriate sources for production of pulsed C4+ and C6+ ion beams which can be used for cancer therapy accelerators. In fact the test ESIS Krion-6T already now at the solenoid magnetic field only 4.6 T provides more than 10^10 C4+ ions per pulse and about 5*10^9 C6+ ions per pulse. Such ion sources could be suitable for application at synchrotrons. It was also found, that Krion-6T can provide more than 10^11 C6+ ions per second at 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. As for production of 11C radioactive ion beams ESIS can be the most economic kind of ion source. To proof that the special cryogenic cell for pulse injection of gaseous species into electron string was successfully tested using the ESIS Krion-2M.
Is the Universal String Axion the QCD Axion
Gaillard, Mary K.; Kain, Ben
2005-10-14T23:59:59.000Z
We consider the class of effective supergravity theories from the weakly coupled heterotic string in which local supersymmetry is broken by gaugino condensation in a hidden sector, with dilaton stabilization achieved through corrections to the classical dilaton Kahler potential. If there is a single hidden condensing (simple) gauge group, the axion is massless (up to contributions from higher dimension operators) above the QCD condensation scale. We show how the standard relation between the axion mass and its Planck scale coupling constant is modified in this class of models due to a contribution to the axion-gluon coupling that appears below the scale of supersymmetry breaking when gluinos are integrated out. In particular there is a point of enhanced symmetry in parameter space where the axion mass is suppressed. We revisit the question of the universal axion as the Peccei-Quinn axion in the light of these results, and find that the strong CP problem is avoided in most compactifications of the weakly coupled heterotic string.
String-Net Models with $Z_N$ Fusion Algebra
Ling-Yan Hung; Yidun Wan
2012-12-19T23:59:59.000Z
We study the Levin-Wen string-net model with a $Z_N$ type fusion algebra. Solutions of the local constraints of this model correspond to $Z_N$ gauge theory and double Chern-simons theories with quantum groups. For the first time, we explicitly construct a spin-$(N-1)/2$ model with $Z_N$ gauge symmetry on a triangular lattice as an exact dual model of the string-net model with a $Z_N$ type fusion algebra on a honeycomb lattice. This exact duality exists only when the spins are coupled to a $Z_N$ gauge field living on the links of the triangular lattice. The ungauged $Z_N$ lattice spin models are a class of quantum systems that bear symmetry-protected topological phases that may be classified by the third cohomology group $H^3(Z_N,U(1))$ of $Z_N$. Our results apply also to any case where the fusion algebra is identified with a finite group algebra or a quantusm group algebra.
Gravitating superconducting strings with timelike or spacelike currents
Betti Hartmann; Florent Michel
2012-08-20T23:59:59.000Z
We construct gravitating superconducting string solutions of the U(1)_{local} x U(1)_{global} model solving the coupled system of Einstein and matter field equations numerically. We study the properties of these solutions in dependence on the ratio between the symmetry breaking scale and the Planck mass. Using the macroscopic stability conditions formulated by Carter, we observe that the coupling to gravity allows for a new stable region that is not present in the flat space-time limit. We match the asymptotic metric to the Kasner metric and show that the relations between the Kasner coefficients and the energy per unit length and tension suggested previously are well fulfilled for symmetry breaking scale much smaller than the Planck mass. We also study the solutions to the geodesic equation in this space-time. While geodesics in the exterior space-time of standard cosmic strings are just straight lines, test particles experience a force in a general Kasner space-time and as such bound orbits are possible.
Stringent phenomenological investigation into heterotic string optical unification
Perkins, J.; Dundee, B.; Obousy, R.; Cleaver, G. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Hatten, S. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Walla Walla College, 204 South College Avenue, College Place, Washington 99324 (United States); Kasper, E. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Robinson, M. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Department of Physics, Auburn University, Auburn, Alabama 36849 (United States); Sloan, C. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Department of Physics, College of Charleston, Charleston, South Carolina 29424 (United States); Stone, K. [Center for Astrophysics, Space Physics and Engineering Research Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States); Department of Physics, East Tennessee State University, Johnson City, Tennessee 37614 (United States)
2007-01-15T23:59:59.000Z
For the weakly coupled heterotic string (WCHS) there is a well-known factor of 20 conflict between the minimum string coupling unification scale, {lambda}{sub H}{approx}5x10{sup 17} GeV, and the projected minimal supersymmetric standard model (MSSM) gauge coupling unification scale, {lambda}{sub U}{approx}2.5x10{sup 16} GeV, assuming an intermediate scale desert (ISD). From a bottom-up approach, renormalization effects of intermediate scale MSSM-charged exotics (ISME), which are endemic to quasirealistic string models, can resolve this issue by pushing the MSSM scale up to the string scale. However, for a generic string model, this implies that the projected {lambda}{sub U} unification under the ISD assumption is accidental. If the true unification scale is {lambda}{sub H} > or approx. 5.0x10{sup 17} GeV, is it possible that an illusionary unification at {lambda}{sub U}=2.5x10{sup 17} GeV in the ISD scenario is not accidental? (This is an issue recently raised again by Binetruy et al..) Optical unification suggests that {lambda}{sub U} might not be accidental. Through its ISME constraints, optical unification offers a mechanism whereby a generic MSSM scale {lambda}{sub U}<{lambda}{sub H} is guaranteed. A WCHS model was recently constructed that could yield optical unification, depending on the availability of anomaly-cancelling D- and F-flat directions that meet optical unification ISME requirements. We report the results of a systematic investigation of the optical unification properties of a subset of flat directions of this model that are stringently flat. Stringent flat directions do not require significant fine-tuning and can be easily guaranteed to be F-flat to all finite order (or to at least a given finite order consistent with electroweak scale supersymmetry breaking). They are the likely roots of more complicated (and arguably, more finely tuned) flat directions. To realize optical unification, a flat direction must keep all exotic triplets and doublets massless down to an intermediate mass scale, except for three extra pairs of Higgs which must acquire MSSM (or higher) scale mass. Additionally, six out of seven pairs of exotic hypercharged non-Abelian singlets must acquire MSSM (or higher) scale mass, while the remaining pair remains massless down to the intermediate scale. Our investigation revealed that the best stringent directions could induce MSSM scale or higher mass to at most three of the six pairs of exotic singlets, and to only two out of three pairs of exotic Higgs. Each of these stringent flat directions keeps all of the exotic triplets and remaining exotic doublets massless down to an intermediate scale. Thus, some fine-tuning away from stringent flat directions is necessary, if it is possible for an additional three pairs of exotic hypercharged singlets and one more pair of extra Higgs to become MSSM scale massive. Future research may indicate if such flat directions exist. This paper is a product of the 2003-2004 NSF REU program at Baylor University.
Collective String Interactions in AdS/QCD and High-Multiplicity pA Collisions
Iatrakis, Ioannis; Shuryak, Edward
2015-01-01T23:59:59.000Z
QCD strings originate from high-energy scattering in the form of Reggions and Pomerons, and have been studied in some detail in lattice numerical simulations. Production of multiple strings, with their subsequent breaking, is now a mainstream model of high energy $pp$ and $pA$ collisions. Recent LHC experiments revealed that high multiplicity end of such collisions show interesting collective effects. This ignited an interest in the interaction of QCD strings and multi-string dynamics. Holographic models, collectively known as AdS/QCD, developed in the last decade, describe both hadronic spectroscopy and basic thermodynamics, but so far no studies of the QCD strings have been done in this context. The subject of this paper is to do this. First, we study in more detail the scalar sector of hadronic spectroscopy, identifying "glueballs" and "scalar mesons," and calculate the degree of their mixing. The QCD strings, holographic images of the fundamental strings, thus have a "gluonic core" and a "sigma cloud." Th...
CONSTRAINING THE STRING GAUGE FIELD BY GALAXY ROTATION CURVES AND PERIHELION PRECESSION OF PLANETS
Cheung, Yeuk-Kwan E.; Xu Feng, E-mail: cheung@nju.edu.cn [Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)
2013-09-01T23:59:59.000Z
We discuss a cosmological model in which the string gauge field coupled universally to matter gives rise to an extra centripetal force and will have observable signatures on cosmological and astronomical observations. Several tests are performed using data including galaxy rotation curves of 22 spiral galaxies of varied luminosities and sizes and perihelion precessions of planets in the solar system. The rotation curves of the same group of galaxies are independently fit using a dark matter model with the generalized Navarro-Frenk-White (NFW) profile and the string model. A remarkable fit of galaxy rotation curves is achieved using the one-parameter string model as compared to the three-parameter dark matter model with the NFW profile. The average {chi}{sup 2} value of the NFW fit is 9% better than that of the string model at a price of two more free parameters. Furthermore, from the string model, we can give a dynamical explanation for the phenomenological Tully-Fisher relation. We are able to derive a relation between field strength, galaxy size, and luminosity, which can be verified with data from the 22 galaxies. To further test the hypothesis of the universal existence of the string gauge field, we apply our string model to the solar system. Constraint on the magnitude of the string field in the solar system is deduced from the current ranges for any anomalous perihelion precession of planets allowed by the latest observations. The field distribution resembles a dipole field originating from the Sun. The string field strength deduced from the solar system observations is of a similar magnitude as the field strength needed to sustain the rotational speed of the Sun inside the Milky Way. This hypothesis can be tested further by future observations with higher precision.
C. Pajares; D. Sousa; R. A. Vázquez
2000-05-31T23:59:59.000Z
At high gluon or string densities, gluons' saturation or the strong interaction among strings, either forming colour ropes or giving rise to string's percolation, induces a strong suppression in the particle multiplicities produced at high energy. This suppression implies important modifications on cosmic ray shower development. In particular, it is shown that it affects the depth of maximum, the elongation rate, and the behaviour of the number of muons at energies around 10^{17}-10^{18} eV. The existing cosmic ray data point out in the same direction.
On the Causal Structure of Spinning Einstein-Yang-Mills-Higgs Strings
Reinoud J. Slagter
1997-10-10T23:59:59.000Z
It is claimed that it will be exceedingly unlikely to obtain CTC's in the spacetime of a spinning EYMH-string. It is conjectured that the pathological problems concerning the induced angular momentum and helical structure of time that afflict the U(1)-gauge string, will be solved in the non-abelian YM string model. In the pure YM case we find regular solutions, which resembles the abelian counterpart solutions but without causality violating regions. Just as in the spherical symmetric case, there will be probably critical behavior of the field equations at the threshold of blackhole masses.
Sustainability of multi-field inflation and bound on string scale
Jinn-Ouk Gong
2009-02-11T23:59:59.000Z
We study the effects of the interaction terms between the inflaton fields on the inflationary dynamics in multi-field models. With power law type potential and interactions, the total number of e-folds may get considerably reduced and can lead to unacceptably short period of inflation. Also we point out that this can place a bound on the characteristic scale of the underlying theory such as string theory. Using a simple multi-field chaotic inflation model from string theory, the string scale is constrained to be larger than the scale of grand unified theory.
Airy Equation for the Topological String Partition Function in a Scaling Limit
Alim, Murad; Zhou, Jie
2015-01-01T23:59:59.000Z
We use the polynomial formulation of the holomorphic anomaly equations governing perturbative topological string theory to derive the free energies in a scaling limit to all orders in perturbation theory for any Calabi-Yau threefold. The partition function in this limit satisfies an Airy differential equation in a rescaled topological string coupling. One of the two solutions of this equation gives the perturbative expansion and the other solution provides geometric hints of the non-perturbative structure of topological string theory. Both solutions can be expanded naturally around strong coupling.
Wave and quantum properties of peptide strings: defining a helix in spacetime
Razvan Tudor Radulescu
2009-04-25T23:59:59.000Z
Previous studies have described the concept of peptide strings in qualitative terms and illustrated it by applying its corrolaries in order to elucidate basic questions in oncology and rheumatology. The present investigation is the first to quantify these potential sub- and transcellular phenomena. Accordingly, the propagation of peptide strings is proposed here to occur by way of waves that in turn are subject to the energy equation established by Planck. As a result of these insights, widespread future applications can now be envisaged for peptide strings both in molecular medicine and quantum optics.
Mapping Kitaev's quantum double lattice models to Levin and Wen's string-net models
Oliver Buerschaper; Miguel Aguado
2009-10-29T23:59:59.000Z
We exhibit a mapping identifying Kitaev's quantum double lattice models explicitly as a subclass of Levin and Wen's string net models via a completion of the local Hilbert spaces with auxiliary degrees of freedom. This identification allows to carry over to these string net models the representation-theoretic classification of the excitations in quantum double models, as well as define them in arbitrary lattices, and provides an illustration of the abstract notion of Morita equivalence. The possibility of generalising the map to broader classes of string nets is considered.
Closed String Thermodynamics and a Blue Tensor Spectrum
Robert H. Brandenberger; Ali Nayeri; Subodh P. Patil
2014-03-26T23:59:59.000Z
The BICEP-2 team has reported the detection of primordial cosmic microwave background B-mode polarization, with hints of a suppression of power at large angular scales relative to smaller scales. Provided that the B-mode polarization is due to primordial gravitational waves, this might imply a blue tilt of the primordial gravitational wave spectrum. Such a tilt would be incompatible with standard inflationary models, although it was predicted some years ago in the context of a mechanism that thermally generates the primordial perturbations through a Hagedorn phase of string cosmology. The purpose of this note is to encourage greater scrutiny of the data with priors informed by a model that is immediately falsifiable, but which \\textit{predicts} features that might be favoured by the data-- namely a blue tensor tilt with an induced and complimentary red tilt to the scalar spectrum, with a naturally large tensor to scalar ratio that relates to both.
D-brane Instantons in Type II String Theory
Blumenhagen, Ralph; /Munich, Max Planck Inst.; Cvetic, Mirjam; /Pennsylvania U.; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Weigand, Timo; /SLAC
2009-06-19T23:59:59.000Z
We review recent progress in determining the effects of D-brane instantons in N=1 supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract D-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function and higher fermionic F-terms. This includes a discussion of multi-instanton effects and the implications of background fluxes for the instanton sector. Our presentation also highlights, but is not restricted to the computation of D-brane instanton effects in quiver gauge theories on D-branes at singularities. We then summarize the concrete consequences of stringy D-brane instantons for the construction of semi-realistic models of particle physics or SUSY-breaking in compact and non-compact geometries.
Nonreciprocal wave scattering on nonlinear string-coupled oscillators
Stefano Lepri; Arkady Pikovsky
2014-10-29T23:59:59.000Z
We study scattering of a periodic wave in a string on two lumped oscillators attached to it. The equations can be represented as a driven (by the incident wave) dissipative (due to radiation losses) system of delay differential equations of neutral type. Nonlinearity of oscillators makes the scattering non-reciprocal: the same wave is transmitted differently in two directions. Periodic regimes of scattering are analysed approximately, using amplitude equation approach. We show that this setup can act as a nonreciprocal modulator via Hopf bifurcations of the steady solutions. Numerical simulations of the full system reveal nontrivial regimes of quasiperiodic and chaotic scattering. Moreover, a regime of a "chaotic diode", where transmission is periodic in one direction and chaotic in the opposite one, is reported.
Anthropic reasoning in multiverse cosmology and string theory
Steven Weinstein
2006-06-08T23:59:59.000Z
Anthropic arguments in multiverse cosmology and string theory rely on the weak anthropic principle (WAP). We show that the principle, though ultimately a tautology, is nevertheless ambiguous. It can be reformulated in one of two unambiguous ways, which we refer to as WAP_1 and WAP_2. We show that WAP_2, the version most commonly used in anthropic reasoning, makes no physical predictions unless supplemented by a further assumption of "typicality", and we argue that this assumption is both misguided and unjustified. WAP_1, however, requires no such supplementation; it directly implies that any theory that assigns a non-zero probability to our universe predicts that we will observe our universe with probability one. We argue, therefore, that WAP_1 is preferable, and note that it has the benefit of avoiding the inductive overreach characteristic of much anthropic reasoning.
String compactification, QCD axion and axion-photon-photon coupling
Kang-Sin Choi; Ian-Woo Kim; Jihn E. Kim
2007-01-13T23:59:59.000Z
It is pointed out that there exist a few problems to be overcome toward an observable sub-eV QCD axion in superstring compactification. We give a general expression for the axion decay constant. For a large domain wall number $N_{DW}$, the axion decay constant can be substantially lowered from a generic value of a scalar singlet VEV. The Yukawa coupling structure in the recent $Z_{12-I}$ model is studied completely, including the needed nonrenormalizable terms toward realistic quark and lepton masses. In this model we find an approximate global symmetry and vacuum so that a QCD axion results but its decay constant is at the GUT scale. The axion-photon-photon coupling is calculated for a realistic vacuum satisfying the quark and lepton mass matrix conditions. It is the first time calculation of $c_{a\\gamma\\gamma}$ in realistic string compactifications: $c_{a\\gamma\\gamma}={5/3}-1.93\\simeq -0.26$.
"Kerrr" black hole: the Lord of the String
Smailagic, Anais
2010-01-01T23:59:59.000Z
Kerrr in the title is not a typo. The third "r" stands for "regular", in the sense of pathology-free, rotating black hole. We exhibit a long search-for, exact, Kerr-like, solution of the Einstein equations with novel features: i) no curvature ring singularity; ii) no "anti-gravity" universe with causality violating timelike closed world-lines; iii) no "super-luminal" matter disk. The ring singularity is replaced by a classical, circular, rotating string with Planck tension representing the inner engine driving the rotation of all the surrounding matter. The resulting geometry is regular and smoothly interpolates among inner Minkowski space, borderline deSitter and outer Kerr universe. The key ingredient to cure all unphysical features of the ordinary Kerr black hole is the choice of a "noncommutative geometry inspired" matter source as the input for the Einstein equations, in analogy with spherically symmetric black holes described in earlier works.
Superconducting Cosmic Strings and One Dimensional Extended Supersymmetric Algebras
V. K. Oikonomou
2014-04-30T23:59:59.000Z
In this article we study in detail the supersymmetric structures that underlie the system of fermionic zero modes around a superconducting cosmic string. Particularly, we extend the analysis existing in the literature on the one dimensional $N=2$ supersymmetry and we find multiple $N=2$, $d=1$ supersymmetries. In addition, compact perturbations of the Witten index of the system are performed and we find to which physical situations these perturbations correspond. More importantly, we demonstrate that there exists a much more rich supersymmetric structure underlying the system of fermions with $N_f$ flavors and these are $N$-extended supersymmetric structures with non-trivial topological charges, with "$N$" depending on the fermion flavors.
Abbasi, R.; Aguilar, J. A.; Andeen, K.; Baker, M.; BenZvi, S. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Abdou, Y. [Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium); Abu-Zayyad, T. [Department of Physics, University of Wisconsin, River Falls, WI 54022 (United States); Adams, J. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Ahlers, M. [Department of Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Auffenberg, J.; Becker, K.-H. [Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany); Bai, X. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Barwick, S. W. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Bay, R. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Bazo Alba, J. L.; Benabderrahmane, M. L. [DESY, D-15735 Zeuthen (Germany); Beattie, K. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Beatty, J. J. [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Bechet, S. [Universite Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium); Becker, J. K. [Fakultaet fuer Physik and Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Collaboration: IceCube Collaboration; and others
2012-01-01T23:59:59.000Z
This paper presents four searches for flaring sources of neutrinos using the IceCube neutrino telescope. For the first time, a search is performed over the entire parameter space of energy, direction, and time with sensitivity to neutrino flares lasting between 20 {mu}s and a year duration from astrophysical sources. Searches that integrate over time are less sensitive to flares because they are affected by a larger background of atmospheric neutrinos and muons that can be reduced by the use of additional timing information. Flaring sources considered here, such as active galactic nuclei, soft gamma-ray repeaters, and gamma-ray bursts, are promising candidate neutrino emitters. Two searches are 'untriggered' in the sense that they look for any possible flare in the entire sky and from a predefined catalog of sources from which photon flares have been recorded. The other two searches are triggered by multi-wavelength information on flares from blazars and from a soft gamma-ray repeater. One triggered search uses lightcurves from Fermi-LAT which provides continuous monitoring. A second triggered search uses information where the flux states have been measured only for short periods of time near the flares. The untriggered searches use data taken by 40 strings of IceCube between 2008 April 5 and 2009 May 20. The triggered searches also use data taken by the 22-string configuration of IceCube operating between 2007 May 31 and 2008 April 5. The results from all four searches are compatible with a fluctuation of the background.
Mechanism of the Cassie-Wenzel transition via the atomistic and continuum string methods
Alberto Giacomello; Simone Meloni; Marcus Mueller; Carlo Massimo Casciola
2014-11-17T23:59:59.000Z
The string method is a general and flexible strategy to compute the most probable transition path for an activated process (rare event). We apply here the atomistic string method in the density field to the Cassie-Wenzel transition, a central problem in the field of superhydrophobicity. We discuss in detail the mechanism of wetting of a submerged hydrophobic cavity of nanometer size and its dependence on the geometry of the cavity. Furthermore, we discuss the algorithmic analogies between the string method and CREaM [Giacomello et al., Phys. Rev. Lett. 109, 226102 (2012)], a method inspired by the string that allows for a faster and simpler computation of the mechanism and of the free-energy profiles of the wetting process. This approach is general and can be employed in mesoscale and macroscopic calculations.
First LIGO search for gravitational wave bursts from cosmic (super)strings
Zucker, Michael E.
We report on a matched-filter search for gravitational wave bursts from cosmic string cusps using LIGO data from the fourth science run (S4) which took place in February and March 2005. No gravitational waves were detected ...
Constraints on Cosmic Strings from the LIGO-Virgo Gravitational-Wave Detectors
Aggarwal, Nancy
Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we ...
Dilaton and axion bremsstrahlung from collisions of cosmic (super)strings
E. Yu. Melkumova; D. V. Gal'tsov; K. Salehi
2006-12-26T23:59:59.000Z
We calculate dilaton and axion radiation generated in the collision of two straight initially unexcited strings and give a rough cosmological estimate of dilaton and axion densities produced via this mechanism in the early universe.
Splitting of Folded Strings in AdS_4*CP^3
Jun-Bao Wu
2012-08-04T23:59:59.000Z
We study classically splitting of two kinds of folded string solutions in AdS_4*CP^3. Conserved charges of the produced fragments are computed for each case. We find interesting patterns among these conserved charges.
Young, Diana S. (Diana Santos), 1975-
2007-01-01T23:59:59.000Z
Virtuosic bowed string performance in many ways exemplifies the incredible potential of human physical performance and expression. Today, a great deal is known about the physics of the violin family and those factors ...
High-Energy String Scattering Amplitudes and Signless Stirling Number Identity
Jen-Chi Lee; Catherine H. Yan; Yi Yang
2012-07-18T23:59:59.000Z
We give a complete proof of a set of identities (7) proposed recently from calculation of high-energy string scattering amplitudes. These identities allow one to extract ratios among high-energy string scattering amplitudes in the fixed angle regime from high-energy amplitudes in the Regge regime. The proof is based on a signless Stirling number identity in combinatorial theory. The results are valid for arbitrary real values $L$ rather than only for $L=0,1$ proved previously. The identities for non-integer real value $L$ were recently shown to be realized in high-energy compactified string scattering amplitudes [He S., Lee J.C., Yang Y., arXiv:1012.3158]. The parameter $L$ is related to the mass level of an excited string state and can take non-integer values for Kaluza-Klein modes.
Methods and systems for determining angular orientation of a drill string
Cobern, Martin E. (Cheshire, CT)
2010-03-23T23:59:59.000Z
Preferred methods and systems generate a control input based on a periodically-varying characteristic associated with the rotation of a drill string. The periodically varying characteristic can be correlated with the magnetic tool face and gravity tool face of a rotating component of the drill string, so that the control input can be used to initiate a response in the rotating component as a function of gravity tool face.
Can a self-gravitating thin cosmic string obey the Nambu-Goto dynamics ?
B. Boisseau; C. Charmousis; B. Linet
1997-10-14T23:59:59.000Z
We assume that a self-gravitating string is locally described by a thin tube of matter represented by a ``smoothed conical metric''. If we impose a specific constraint on the model of string then its central line obeys the Nambu-Goto dynamics in the limit where the radius of the tube tends to zero. If no constraint is added then the world sheet of the central line is totally geodesic.
Semiclassical circular strings in AdS{sub 5} and 'long' gauge field strength operators
Park, I.Y.; Tirziu, A.; Tseytlin, A.A. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)
2005-06-15T23:59:59.000Z
We consider circular strings rotating with equal spins S{sub 1}=S{sub 2}=S in two orthogonal planes in AdS{sub 5} and suggest that they may be dual to long gauge-theory operators built out of self-dual components of gauge field strength. As was found in hep-th/0404187, the one-loop anomalous dimensions of the such gauge-theory operators are described by an antiferromagnetic XXX{sub 1} spin chain and scale linearly with length L>>1. We find that in the case of rigid rotating string both the classical energy E{sub 0} and the 1-loop string correction E{sub 1} depend linearly on the spin S (within the stability region of the solution). This supports the identification of the rigid rotating string with the gauge-theory operator corresponding to the maximal-spin (ferromagnetic) state of the XXX{sub 1} spin chain. The energy of more general rotating and pulsating strings also happens to scale linearly with both the spin and the oscillation number. Such solutions should be dual to other lower-spin states of the spin chain, with the antiferromagnetic ground state presumably corresponding to the string pulsating in two planes with no rotation.
Cosmic strings in $f\\left(R,L_m\\right)$ gravity
Tiberiu Harko; Matthew J. Lake
2015-01-17T23:59:59.000Z
We consider Kasner type static, cylindrically symmetric interior string solutions in the $f\\left(R,L_m\\right)$ theory of modified gravity. The physical properties of the string are described by an anisotropic energy-momentum tensor satisfying the condition $T_t^t=T_z^z$; that is, the energy density of the string along the $z$-axis is equal to minus the string tension. As a first step in our study we obtain the gravitational field equations in the $f\\left(R,L_m\\right)$ theory for a general static, cylindrically symmetric metric, and then for a Kasner type metric, in which the metric tensor components have a power law dependence on the radial coordinate $r$. String solutions in two particular modified gravity models are investigated in detail. The first is the so-called "exponential" modified gravity, in which the gravitational action is proportional to the exponential of the sum of the Ricci scalar and matter Lagrangian, and the second is the "self-consistent model", obtained by explicitly determining the gravitational action from the field equations under the assumption of a power law dependent matter Lagrangian. In each case, the thermodynamic parameters of the string, as well as the precise form of the matter Lagrangian, are explicitly obtained.
Energy Production in the Formation of a Finite Thickness Cosmic String
I. Brevik; A. G. Frøseth
1999-09-29T23:59:59.000Z
The classical electromagnetic modes outside a long, straight, superconducting cosmic string are calculated, assuming the string to be surrounded by a superconducting cylindric surface of radius R. Thereafter, by use of a Bogoliubov-type argument, the electromagnetic energy W produced per unit length in the lowest two modes is calculated when the string is formed "suddenly". The essential new element in the present analysis as compared with prior work of Parker [Phys. Rev. Lett. {\\bf 59}, 1369 (1987)] and Brevik and Toverud [Phys. Rev. D {\\bf 51}, 691 (1995)], is that the radius {\\it a} of the string is assumed finite, thus necessitating Neumann functions to be included in the fundamental modes. We find that the theory is changed significantly: W is now strongly concentrated in the lowest mode $(m,s)=(0,1)$, whereas the proportionality $W \\propto (G\\mu /t)^2$ that is characteristic for zero-width strings is found in the next mode (1,1). Here G is the gravitational constant, $\\mu$ the string mass per unit length, and t the GUT time.
Proton Stability, Gauge Coupling Unification and a Light $Z^\\prime$ in Heterotic-string Models
Alon E. Faraggi; Viraf M. Mehta
2013-06-11T23:59:59.000Z
We explore the phenomenological viability of a light Z' in heterotic-string models, whose existence has been motivated by proton stability arguments. A class of quasi-realistic string models that produce such a viable Z' are the Left-Right Symmetric (LRS) heterotic-string models in the free fermionic formulation. A key feature of these models is that the matter charges under U(1)_Z' do not admit an E6 embedding. The light Z' in the LRS heterotic-string models forbids baryon number violating operators, while allowing lepton number violating operators, hence suppressing proton decay yet allowing for sufficiently small neutrino masses via a seesaw mechanism. We show that the constraints imposed by the gauge coupling data and heterotic-string coupling unification nullify the viability of a light Z' in these models. We further argue that agreement with the gauge coupling data necessitates that the U(1)_Z' charges admit an E6 embedding. We discuss how viable string models with this property may be constructed.
TeV Scale Strings and Scattering Amplitudes at the LHC
Dean Carmi
2014-11-07T23:59:59.000Z
We study aspects of TeV string scale models of intersecting D-branes. The gauge bosons arise from strings ending on stacks of D-branes, whereas chiral matter arises from strings stretched between intersecting D-branes. Our focus is on scattering amplitudes (at tree-level), Regge states (string excitations), and collider phenomenology. Achieving a low string scale is possible in models of Large extra dimensions. At the LHC, a low enough string scale implies that cross sections will deviate from their standard model predictions. Moreover, Regge states as well as Kaluza-Klein states and winding states may be produced. In a large class of intersecting D-brane models, the quark-gluon amplitudes with at most 2 quarks turn out to be independent of the geometry of the extra dimensions. Therefore these type of amplitudes, which we call "universal amplitudes", are model independent. The universal amplitudes involve exchanges of Regge states only, whereas amplitudes with more then 2 quarks also involve exchanges of KK and winding states. The main computational part is concerned with suggesting methods to calculate the decay widths of the Regge states, and with the formalism for treating amplitudes containing exchanges of higher spin particles. Also included is a large review part.
Zhou, Quanlin
2011-01-01T23:59:59.000Z
by pressure perturbation from geologic carbon sequestration: Static and dynamic evaluations. Int. J.elsevier.com/locate/ijggc Brine flow up a well caused by pressure perturbation from geologic carbon sequestration: Static carbon sequestration (GCS) has drawn increasing con- sideration as a promising method to mitigate
Belavin, Alexander
2015-01-01T23:59:59.000Z
The fermionic NSR string possesses a hidden N = 2 superconformal algebra on the world-sheet. In this work, we show how to use an isomorphism of this algebra, the so-called spectral flow, for construction of a subspace of physical states of the string, on which space-time supersymmetry acts. This construction is an alternative to the GSO-projection in string theory.
Reheating-volume measure in the string theory landscape
Winitzki, Sergei [Department of Physics, Ludwig-Maximilians University, Munich (Germany)
2008-12-15T23:59:59.000Z
I recently proposed the ''reheating-volume'' (RV) prescription as a possible solution to the measure problem in ''multiverse'' cosmology. The goal of this work is to extend the RV measure to scenarios involving bubble nucleation, such as the string theory landscape. In the spirit of the RV prescription, I propose to calculate the distribution of observable quantities in a landscape that is conditioned in probability to nucleate a finite total number of bubbles to the future of an initial bubble. A general formula for the relative number of bubbles of different types can be derived. I show that the RV measure is well defined and independent of the choice of the initial bubble type, as long as that type supports further bubble nucleation. Applying the RV measure to a generic landscape, I find that the abundance of Boltzmann brains is always negligibly small compared with the abundance of ordinary observers in the bubbles of the same type. As an illustration, I present explicit results for a toy landscape containing four vacuum states, and for landscapes with a single high-energy vacuum and a large number of low-energy vacua.
Fuzzy bags, Polyakov loop and gauge/string duality
Fen Zuo
2014-09-10T23:59:59.000Z
Confinement in SU($N$) gauge theory is due to the linear potential between colored objects. At short distances, the linear contribution could be considered as the quadratic correction to the leading Coulomb term. Recent lattice data show that such quadratic corrections also appear in the deconfined phase, in both the thermal quantities and the Polyakov loop. These contributions are studied systematically employing the gauge/string duality. "Confinement" in ${\\mathcal N}=4$ SU($N$) Super Yang-Mills (SYM) theory could be achieved kinematically when the theory is defined on a compact space manifold. In the large-$N$ limit, deconfinement of ${\\mathcal N}=4$ SYM on $\\mathbb{S}^3$ at strong coupling is dual to the Hawking-Page phase transition in the global Anti-de Sitter spacetime. Meantime, all the thermal quantities and the Polyakov loop achieve significant quadratic contributions. Similar results can also be obtained at weak coupling. However, when confinement is induced dynamically through the local dilaton field in the gravity-dilaton system, these contributions can not be generated consistently. This is in accordance with the fact that there is no dimension-2 gauge-invariant operator in the boundary gauge theory. Based on these results, we suspect that quadratic corrections, and also confinement, should be due to global or non-local effects in the bulk spacetime.
Arman Tursunov; Martin Kološ; Zden?k Stuchlík; Bobomurat Ahmedov
2014-09-18T23:59:59.000Z
We study the acceleration of an electric current-carrying and axially-symmetric string loop initially oscillating in the vicinity of a Schwarzschild black hole embedded in an external asymptotically uniform magnetic field. The plane of the string loop is orthogonal to the magnetic field lines and the acceleration of the string loop occurs due to the transmutation effect turning in the deep gravitational field the internal energy of the oscillating strings to the energy of their translational motion along the axis given by the symmetry of the black hole spacetime and the magnetic field. We restrict our attention to the motion of string loop with energy high enough, when it can overcome the gravitational attraction and escape to infinity. We demonstrate that for the current-carrying string loop the transmutation effect is enhanced by the contribution of the interaction between the electric current of the string loop and the external magnetic field and we give conditions that have to be fulfilled for an efficient acceleration. The Schwarzschild black hole combined with the strong external magnetic field can accelerate the current-carrying string loop up to the velocities close to the speed of light $v \\sim c$. Therefore, the string loop transmutation effect can potentially well serve as an explanation for acceleration of highly relativistic jets observed in microquasars and active galactic nuclei.
String-theoretic breakdown of effective field theory near black hole horizons
Matthew Dodelson; Eva Silverstein
2015-04-21T23:59:59.000Z
We investigate the validity of the equivalence principle near horizons in string theory, analyzing the breakdown of effective field theory caused by longitudinal string spreading effects. An experiment is set up where a detector is thrown into a black hole a long time after an early infalling string. Light cone gauge calculations, taken at face value, indicate a detectable level of root-mean-square longitudinal spreading of the initial string as measured by the late infaller. This results from the large relative boost between the string and detector in the near horizon region, which develops automatically despite their modest initial energies outside the black hole and the weak curvature in the geometry. We subject this scenario to basic consistency checks, using these to obtain a relatively conservative criterion for its detectability. In a companion paper, we exhibit longitudinal nonlocality in well-defined gauge-invariant S-matrix calculations, obtaining results consistent with the predicted spreading albeit not in a direct analogue of the black hole process. We discuss applications of this effect to the firewall paradox, and estimate the time and distance scales it predicts for new physics near black hole and cosmological horizons.
Proton stability in grand unified theories, in strings, and in branes
Pran Nath; Pavel Fileviez Perez
2007-04-23T23:59:59.000Z
A broad overview of the current status of proton stability in unified models of particle interactions is given which includes non - supersymmetric unification, SUSY and SUGRA unified models, unification based on extra dimensions, and string-M-theory models. The extra dimensional unification includes 5D and 6D and universal extra dimensional (UED) models, and models based on warped geometry. Proton stability in a wide array of string theory and M theory models is reviewed. These include Calabi-Yau models, grand unified models with Kac-Moody levels $k>1$, a new class of heterotic string models, models based on intersecting D branes, and string landscape models. The destabilizing effect of quantum gravity on the proton is discussed. The possibility of testing grand unified models, models based on extra dimensions and string-M-theory models via their distinctive modes is investigated. The proposed next generation proton decay experiments, HyperK, UNO, MEMPHYS, ICARUS, LANNDD (DUSEL), and LENA would shed significant light on the nature of unification complementary to the physics at the LHC. Mathematical tools for the computation of proton lifetime are given in the appendices. Prospects for the future are discussed.
Hagedorn String Thermodynamics in Curved Spacetimes and near Black Hole Horizons
Thomas G. Mertens
2015-06-25T23:59:59.000Z
This thesis concerns the study of high-temperature string theory on curved backgrounds, generalizing the notions of Hagedorn temperature and thermal scalar to general backgrounds. Chapter 2 contains a review on string thermodynamics in flat space, setting the stage. Chapters 3 and 4 contain the detailed study of the random walk picture in a general curved background. Chapters 5 and 6 then apply this to Rindler space, the near-horizon approximation of a generic (uncharged) black hole. Chapters 7 and 8 contain a study of the AdS3 and BTZ WZW models where we study the thermal spectrum and the resulting random walk picture that emerges. Chapters 9 and 10 attempt to draw general conclusions from the study of the two specific examples earlier: we draw lessons on string thermodynamics in general and on (perturbative) string thermodynamics around black hole horizons. For the latter, we point out a possible link to the firewall paradox. Finally, chapter 11 contains a detailed discussion on the near-Hagedorn (and high-energy) stress tensor in a generic spacetime, the results of which are applied to provide a description of the Bekenstein-Hawking entropy in terms of long string equilibration.
Field Redefinitions, T-duality and Solutions in Closed String Field Theories
Yoji Michishita
2006-04-26T23:59:59.000Z
We investigate classical solutions in closed bosonic string field theory and heterotic string field theory that are obtained order by order starting from solutions of the linearized equations of motion, and we discuss the ``field redefinitions'' which relate massless fields in the string field theory side and the low energy effective theory side. Massless components of the string field theory solutions are not corrected and from them we can infer corresponding solutions in the effective theory: the chiral null model and the pp-wave solution with B-field, which have been known to be alpha'-exact. These two sets of solutions in the two sides look slightly different because of the field redefinitions. It turns out that T-duality is a useful tool to determine them: We show that some part of the field redefinitions can be determined by using the correspondence between T-duality rules in the two sides, irrespective of the detail of the interaction terms and the integrating-out procedure. Applying the field redefinitions, we see that the solutions in the effective theory side are reproduced from the string field theory solutions.
Strings at Finite Temperature: Wilson Lines, Free Energies, and the Thermal Landscape
Keith R. Dienes; Michael Lennek; Menika Sharma
2012-05-25T23:59:59.000Z
According to the standard prescriptions, zero-temperature string theories can be extended to finite temperature by compactifying their time directions on a so-called "thermal circle" and implementing certain orbifold twists. However, the existence of a topologically non-trivial thermal circle leaves open the possibility that a gauge flux can pierce this circle --- i.e., that a non-trivial Wilson line (or equivalently a non-zero chemical potential) might be involved in the finite-temperature extension. In this paper, we concentrate on the zero-temperature heterotic and Type I strings in ten dimensions, and survey the possible Wilson lines which might be introduced in their finite-temperature extensions. We find a rich structure of possible thermal string theories, some of which even have non-traditional Hagedorn temperatures, and we demonstrate that these new thermal string theories can be interpreted as extrema of a continuous thermal free-energy "landscape". Our analysis also uncovers a unique finite-temperature extension of the heterotic SO(32) and $E_8\\times E_8$ strings which involves a non-trivial Wilson line, but which --- like the traditional finite-temperature extension without Wilson lines --- is metastable in this thermal landscape.
Exploring the string axiverse with precision black hole physics
Arvanitaki, Asimina [Berkeley Center for Theoretical Physics, University of California, Berkeley, California, 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California, 94720 (United States); Dubovsky, Sergei [Department of Physics, Stanford University, Stanford, California, 94305 (United States); Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation)
2011-02-15T23:59:59.000Z
It has recently been suggested that the presence of a plenitude of light axions, an Axiverse, is evidence for the extra dimensions of string theory. We discuss the observational consequences of these axions on astrophysical black holes through the Penrose superradiance process. When an axion Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole ''nucleus'' forming a gravitational atom in the sky. The occupation number of superradiant atomic levels, fed by the energy and angular momentum of the black hole, grows exponentially. The black hole spins down and an axion Bose-Einstein condensate cloud forms around it. When the attractive axion self-interactions become stronger than the gravitational binding energy, the axion cloud collapses, a phenomenon known in condensed matter physics as 'bosenova'. The existence of axions is first diagnosed by gaps in the mass vs spin plot of astrophysical black holes. For young black holes the allowed values of spin are quantized, giving rise to ''Regge trajectories'' inside the gap region. The axion cloud can also be observed directly either through precision mapping of the near-horizon geometry or through gravitational waves coming from the bosenova explosion, as well as axion transitions and annihilations in the gravitational atom. Our estimates suggest that these signals are detectable in upcoming experiments, such as Advanced LIGO, AGIS, and LISA. Current black hole spin measurements imply an upper bound on the QCD axion decay constant of 2x10{sup 17} GeV, while Advanced LIGO can detect signals from a QCD axion cloud with a decay constant as low as the GUT scale. We finally discuss the possibility of observing the {gamma}-rays associated with the bosenova explosion and, perhaps, the radio waves from axion-to-photon conversion for the QCD axion.
Holographic light quark jet quenching at RHIC and LHC via the shooting strings
Andrej Ficnar; Steven S. Gubser; Miklos Gyulassy
2014-04-03T23:59:59.000Z
A new shooting string holographic model of jet quenching of light quarks in strongly coupled plasmas is presented to overcome the phenomenological incompatibilities of previous falling string holographic scenarios that emerged when confronted with the recent LHC data. This model is based on strings with finite momentum endpoints that start close to the horizon and lose energy as they approach the boundary. This framework is applied to compute the nuclear modification factor RAA of light hadrons at RHIC and LHC, showing that this model improves greatly the comparison with the recent light hadron suppression data. The effects of the Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry further improve the agreement with the data.
Isometry Group Orbit Quantization of Spinning Strings in AdS_3 x S^3
Martin Heinze; George Jorjadze; Luka Megrelidze
2014-10-13T23:59:59.000Z
Describing the bosonic AdS_3 x S^3 particle and string in SU(1,1) x SU(2) group variables, we provide a Hamiltonian treatment of the isometry group orbits of solutions via analysis of the pre-symplectic form. For the particle we obtain a one-parameter family of orbits parameterized by creation-annihilation variables, which leads to the Holstein-Primakoff realization of the isometry group generators. The scheme is then applied to spinning string solutions characterized by one winding number in AdS_3 and two winding numbers in S^3. We find a two-parameter family of orbits, where quantization again provides the Holstein-Primakoff realization of the symmetry generators with an oscillator type energy spectrum. Analyzing the minimal energy at strong coupling we verify the spectrum of short strings at special values of winding numbers.
High Redshift Gamma-Ray Bursts: Observational Signatures of Superconducting Cosmic Strings?
K. S. Cheng; Yun-Wei Yu; T. Harko
2010-06-11T23:59:59.000Z
The high-redshift gamma-ray bursts (GRBs), GRBs 080913 and 090423, challenge the conventional GRB progenitor models by their short durations, typical for short GRBs, and their high energy releases, typical for long GRBs. Meanwhile, the GRB rate inferred from high-redshift GRBs also remarkably exceeds the prediction of the collapsar model, with an ordinary star formation history. We show that all these contradictions could be eliminated naturally, if we ascribe some high-redshift GRBs to electromagnetic bursts of superconducting cosmic strings. High-redshift GRBs could become a reasonable way to test the superconducting cosmic string model, because the event rate of cosmic string bursts increases rapidly with increasing redshifts, whereas the collapsar rate decreases.
Quantum strings in AdS5 x S5 and AdS/CFT duality
A. A. Tseytlin
2009-09-23T23:59:59.000Z
We review some recent progress in understanding the spectrum of energies/dimensions of strings/operators in AdS5 x S5 -- planar N=4 super Yang-Mills correspondence. We consider leading strong coupling corrections to the energy of lightest massive string modes in AdS5 x S5, which should be dual to members of the Konishi operator multiplet in the SYM theory. This determines the general structure of strong-coupling expansion of the anomalous dimension of the Konishi operator. Following arXiv:0906.4294 we use 1-loop results for semiclassical string states to extract information about the leading coefficients in this expansion.
A Statistic for identifying cosmic string wakes and other sheet-like structure
James Robinson; Andreas Albrecht
1996-02-26T23:59:59.000Z
We describe an implementation of the structure functions of Babul \\& Starkman, in order to quantify the ``sheet-like'' nature of a distribution of matter. We test this statistic on a toy model describing cosmic string wakes, and show that it does a better job than other statistics which have been proposed for distinguishing non-Gaussianity in the form of sheets. We conclude that the most favoured cosmic string model is unlikely to produce a significant increase in the sheet-like nature of the matter distribution beyond that which occurs in Gaussian models (with the same power spectrum) due to the formation of Zeldovich pancakes. Although the statistic was developed in the context of cosmic string wake formation, we expect it to be useful for comparing the observed galaxy distribution with a wide range of theoretical models with different power spectra.
Lake, Matthew J
2015-01-01T23:59:59.000Z
The discovery of a large number of supermassive black holes at redshifts $z> 6$, when the Universe was only nine hundred million years old, has raised the fundamental question of how such massive compact objects could form in a (cosmologically) short time interval. Each of the proposed standard scenarios for black hole formation, involving rapid accretion of seed black holes, or black hole mergers, faces severe theoretical difficulties in explaining the short time formation of supermassive objects. In the present Letter, we propose an alternative scenario for the formation of supermassive black holes in the early Universe in which energy transfer from superconducting cosmic strings, piercing small seed black holes, is the main physical process leading to rapid mass increase. The increase in mass of a primordial seed black hole pierced by two antipodal strings is estimated and it is shown that this increases linearly in time. Due to the high energy transfer rate from the cosmic strings, we find that supermassi...
Van Den Eijnden, Eric
On-the-fly string method for minimum free energy paths calculation Luca Maragliano *, Eric Vanden and simplified version of the string method in collective variables for computing minimum free energy paths) the minimum free energy path (MFEP) plays an important role. Given a set of collective variables to describe
Full-power test of a string of magnets comprising a half-cell of the Superconducting Super Collider
Burgett, W.; Christianson, M.; Coombes, R. [and others
1992-10-01T23:59:59.000Z
In this paper we describe the full-powered operation of a string of industrially-fabricated magnets comprising a half-cell of the Superconducting Super Collider (SSC). The completion of these tests marks the first successful operation of a major SSC subsystem. The five 15-m long dipole magnets in the string had an aperture of 50 mm and the single 5-m long quadrupole aperture was 40 mm. Power and cryogenic connections were made to the string through spool pieces that are prototypes for SSC operations. The string was cooled to cryogenic temperatures in early July, 1992, and power tests were performed at progressively higher currents up to the nominal SSC operating point above 6500 amperes achieved in mid-August. In this paper we report on the electrical and cryogenic performance of the string components and the quench protection system during these initial tests.
Open strings in the plane wave background II: Superalgebras and Spectra
Kostas Skenderis; Marika Taylor
2002-12-16T23:59:59.000Z
In hep-th/0211011 we started a systematic investigation of open strings in the plane wave background. In this paper we continue the analysis by discussing the superalgebras of conserved charges, the spectra of open strings, and the spectra of DBI fluctuations around D-brane embeddings. We also derive the gluing conditions for corresponding boundary states and analyze their symmetries. All results are consistent with each other, and confirm the existence of additional supersymmetries as previously discussed. We further show that for every symmetry current one can construct a (countably) infinite number of related currents that contain more worldsheet derivatives, and discuss non-local symmetries.
Russian doll spectrum in a non-Abelian string-net ladder
M. D. Schulz; S. Dusuel; J. Vidal
2015-04-09T23:59:59.000Z
We study a string-net ladder in the presence of a string tension. Focusing on the simplest non-Abelian anyon theory with a quantum dimension larger than two, we determine the phase diagram and find a Russian doll spectrum featuring size-independent energy levels as well as highly degenerate zero-energy eigenstates. At the self-dual points, we compute the gap exactly by using a mapping onto the Temperley-Lieb chain. These results are in stark constrast with the ones obtained for Fibonacci or Ising theories.
Reparametrizations and Gauge and General Coordinate Transformations in String Field Theory
Das, Sumit R.; Rubin, Mark A.
1985-10-01T23:59:59.000Z
The authors relate reparametrizations of the parameter ? to point transformations of scalar field in ''loop space,'' the configuration space of string field theory. Formulas are given for the changes induced by these transformations in the infinite set of ''component'' spacetime-tensor fields into which a scalar field on loop space may be decomposed. New derivative operators on loop space are defined, motivated by the parametrization-dependence of the mapping from loop space to spacetime. A generalization to loop space of the Einstein-Hilbert Lagrangian is proposed as a candidate for a 2nd-quantized string Lagrangian not tied to any preferred background geometry.
Kosterlitz-Thouless transition on the worldsheet of the QCD string
Harvey B. Meyer
2005-09-22T23:59:59.000Z
We investigate the properties of the QCD string in the Euclidean SU(N) pure gauge theory when the space-time dimensions transverse to it are periodic. We propose a generalisation of the Luscher-Weisz effective string action for the flux-tube energy levels at finite L_perp. As the size of one transverse dimension is varied, we predict a Kosterlitz-Thouless transition of the worldsheet field theory driven by vortices, after which the periodic component of the worldsheet displacement vector develops a mass gap and the effective central charge drops by one unit. The universal properties of the transition are emphasized.
Jet-fluid string formation and decay in high-energy heavy-ion collisions
M. Isse; T. Hirano; R. Mizukawa; A. Ohnishi; K. Yoshino; Y. Nara
2007-02-22T23:59:59.000Z
We propose a new hadronization mechanism, jet-fluid string (JFS) formation and decay, to understand observables in intermediate to high-$p_{T}$ regions comprehensively. In the JFS model, hard partons produced in jet lose their energy in traversing the QGP fluid, which is described by fully three-dimensional hydrodynamic simulations. When a jet parton escapes from the QGP fluid, it picks up a partner parton from a fluid and forms a color singlet string, then it decays to hadrons. We find that high-$p_T$ $v_2$ values in JFS are about two times larger than in the independent fragmentation model.
Running anti-de Sitter radius from QCD-like strings
Yu-tin Huang; Warren Siegel
2007-07-10T23:59:59.000Z
We consider renormalization effects for a bosonic QCD-like string, whose partons have $1/p^{2}$ propagators instead of Gaussian. Classically this model resembles (the bosonic part of) the projective light-cone (zero-radius) limit of a string on an AdS${}_5$ background, where Schwinger parameters give rise to the fifth dimension. Quantum effects generate dynamics for this dimension, producing an AdS${}_5$ background with a running radius. The projective light-cone is the high-energy limit: Holography is enforced dynamically.
Dynamics of a self-gravitating thin string in scalar-tensor theories of gravitation
B. Boisseau; B. Linet
1997-06-09T23:59:59.000Z
We examine the dynamics of a self-gravitating string in the scalar-tensor theories of gravitation by considering a thin tube of matter to describe it. For a class of solutions, we obtain in the generic case that the extrinsic curvature of the world sheet of the central line is null in the limit where the radius of the string tends to zero. However, if we impose a specific constraint on the behaviour of the solution then we find that only the mean curvature of the world sheet of the central line vanishes which is just the Nambu-Goto dynamics. This analysis can include the massless dilatonic theories of gravity.
Iso-curvature fluctuations through axion trapping by cosmic string wakes
Biswanath Layek
2005-03-07T23:59:59.000Z
We consider wake-like density fluctuations produced by cosmic strings at the quark-hadron transition in the early universe. We show that low momentum axions which are produced through the radiation from the axionic string at an earlier stage, may get trapped inside these wakes due to delayed hadronization in these overdense regions. As the interfaces, bordering the wakes, collapse, the axions pick-up momentum from the walls and finally leave the wake regions. These axions thus can produce large scale iso-curvature fluctuations. We have calculated the detailed profile of these axionic density fluctuations and discuss its astrophysical consequences.
String Tests of 3S1P Configurations for Electric Energy Storage Applications
String Tests of 3S1P Configurations for Electric Energy Storage Applications Prepared for the U.2 Deliverable 2 Report on Results of Storage Tests Prepared by Hawai`i Natural Energy Institute School of OceanPConfigurationsfor ElectricEnergyStorageApplications Matthieu Dubarry and Bor Yann Liaw Hawaii Natural Energy
Electromagnetic plane waves with negative phase velocity in charged black strings
Sharif, M., E-mail: msharif.math@pu.edu.pk; Manzoor, R., E-mail: rubabmanzoor9@yahoo.com [University of the Punjab, Department of Mathematics (Pakistan)
2013-02-15T23:59:59.000Z
We investigate the propagation regions of electromagnetic plane waves with negative phase velocity in the ergosphere of static charged black strings. For such a propagation, some conditions for negative phase velocity are established that depend on the metric components and the choice of the octant. We conclude that these conditions remain unaffected by the negative values of the cosmological constant.
Anomaly constraints and string/F-theory geometry in 6D quantum gravity
Washington Taylor
2010-09-07T23:59:59.000Z
Quantum anomalies, determined by the Atiyah-Singer index theorem, place strong constraints on the space of quantum gravity theories in six dimensions with minimal supersymmetry. The conjecture of "string universality" states that all such theories which do not have anomalies or other quantum inconsistencies are realized in string theory. This paper describes this conjecture and recent work by Kumar, Morrison, and the author towards developing a global picture of the space of consistent 6D supergravities and their realization in string theory via F-theory constructions. We focus on the discrete data for each model associated with the gauge symmetry group and the representation of this group on matter fields. The 6D anomaly structure determines an integral lattice for each gravity theory, which is related to the geometry of an elliptically fibered Calabi-Yau three-fold in an F-theory construction. Possible exceptions to the string universality conjecture suggest novel constraints on low-energy gravity theories which may be identified from the structure of F-theory geometry.
Adrian Ottewill; Peter Taylor
2010-06-30T23:59:59.000Z
We obtain an analytic expression for the vacuum polarization on the horizon of the Schwarzschild black hole threaded by an infinite cosmic string. This calculation relies on a generalized Heine identity for Legendre functions which we derive without using specific properties of the Legendre functions themselves.
Cellular/Molecular The Multiple Functions of Cysteine-String Protein Analyzed
Robertson, Meldrum
, suggesting that the L domain is important, although not essential, for the role of CSP in regulating-string protein (CSP) is important for synaptic transmission. Previous studies revealed multiple defects at neuromuscular junctions (NMJs) of csp null-mutant Drosophila, but whether these defects are independent of each
Comments on the Nekrasov-type formula for E-string theory
Ishii, Takenori
2015-01-01T23:59:59.000Z
We generalise our previous result\\cite{13} to cases with three and four Wilson lines. We show that the Nekrasov-type formula for E-string theory is valid for those cases and the Seiberg-Witten curves are reproduced from the formula. In addition, we show the dependence of the Seiberg-Witten curve on the Wilson lines.
Low energy effective actions and tachyon dynamics from string field theory
Coletti, Erasmo
2005-01-01T23:59:59.000Z
In this thesis we show how to calculate off-shell low energy effective actions and how to study the dynamics of the tachyon from string field theory. We discuss how to obtain an effective action for the massless field and ...
A String Diagram Calculus for Predicate Logic and C. S. Peirce's System Beta
Brady, Geraldine
A String Diagram Calculus for Predicate Logic and C. S. Peirce's System Beta Geraldine Brady, called Beta, is reformulated here in modern terms, using developments in cate- gorical logic with Peirce's system Beta, is shown to be sound and complete with respect to #12;rst-order logic. 1991 Math
On spacetimes with 3-parameter isometry group in string-inspired theory of gravity
P. Klepac
2002-01-13T23:59:59.000Z
Cylindrically symmetric stationary spacetimes are examined in the framework of string-inpired generalized theory of gravity. In four dimensions this theory contains a dilatonic scalar field in addition to gravity. A charged perfect fluid representing fermionic matter is also considered. Explicit solution is given and a discussion of the geometrical properties of the solutions found is carried out.
Martins, R. A. [Centro de Analise Matematica, Geometria e Sistemas Dinamicos, Departamento de Matematica, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal)
2007-08-15T23:59:59.000Z
The recent extension of the standard model to include massive neutrinos in the framework of noncommutative geometry and the spectral action principle involves new scalar fields and their interactions with the usual complex scalar doublet. After ensuring that they bring no unphysical consequences, we address the question of how these fields affect the physics predicted in the Weinberg-Salam theory, particularly in the context of the electroweak phase transition. Applying the Dolan-Jackiw procedure, we calculate the finite temperature corrections, and find that the phase transition is first order. The new scalar interactions significantly improve the stability of the electroweak Z string, through the 'bag' phenomenon described by Vachaspati and Watkins ['Bound states can stabilize electroweak strings', Phys. Lett. B 318, 163-168 (1993)]. (Recently, cosmic strings have climbed back into interest due to a new evidence.) Sourced by static embedded strings, an internal space analogy of Cartan's torsion is drawn, and a possible Higgs-force-like 'gravitational' effect of this nonpropagating torsion on the fermion masses is described. We also check that the field generating the Majorana mass for the {nu}{sub R} is nonzero in the physical vacuum.
Lecture notes on thermodynamics of ideal string gases and its application in cosmology
Lihui Liu
2014-12-05T23:59:59.000Z
In these lecture notes I give a pedagogical introduction to the thermodynamics of ideal string gases. The computation of thermodynamic quantities in the canonical ensemble formalism will be shown in detail with explicit examples. Attention will be given mainly to the thermodynamical consequences of string degrees of freedom, where I will especially address i) the Hagedorn temperature, a critical temperature above which the canonical ensemble description breaks down, which can be the onset point of some instability of the string gas; ii) the phase structure arising from compactification, embodied in the moduli-dependence of the Helmholtz free energy, which corrects the tree-level vacuum and can provide mechanism for moduli stabilization. Then I will briefly explain the implementation of string gas thermodynamics in cosmology, showing a simple example which gives rise to a radiation-dominated early universe. Further phenomenological issues and open questions will be discussed qualitatively with references indicated, including the Hagedorn instability in the resolution of the initial singularity, moduli stabilization, generation of hierarchy, radiative symmetry breaking and primordial cosmological fluctuations.
Transition state-finding strategies for use with the growing string method Anthony Goodrow,1
Bell, Alexis T.
Transition state-finding strategies for use with the growing string method Anthony Goodrow,1 Alexis Efficient identification of transition states is important for understanding reaction mechanisms. Most transition state search algorithms require long computational times and a good estimate of the transition
String and the Strong Force Summary/Review Lecture 9: Spring 2009 Compton Lecture Series
String and the Strong Force Summary/Review Lecture 9: Spring 2009 Compton Lecture Series: From and then in order of decreasing likelihood. By contrast, in the strong force, quantum chromodynamics (QCD complicated array. If you try to draw the interaction of a quark and an anti-quark, you wind up
S-matrix for strings on $\\eta$-deformed AdS5 x S5
Arutyunov, Gleb; Frolov, Sergey
2014-01-01T23:59:59.000Z
We determine the bosonic part of the superstring sigma model Lagrangian on $\\eta$-deformed AdS5 x S5, and use it to compute the perturbative world-sheet scattering matrix of bosonic particles of the model. We then compare it with the large string tension limit of the q-deformed S-matrix and find exact agreement.
S-matrix for strings on $?$-deformed AdS5 x S5
Gleb Arutyunov; Riccardo Borsato; Sergey Frolov
2014-04-07T23:59:59.000Z
We determine the bosonic part of the superstring sigma model Lagrangian on $\\eta$-deformed AdS5 x S5, and use it to compute the perturbative world-sheet scattering matrix of bosonic particles of the model. We then compare it with the large string tension limit of the q-deformed S-matrix and find exact agreement.
Proton Stability and Light $Z^\\prime$ Inspired by String Derived Models
Alon E. Faraggi; Viraf M. Mehta
2011-06-15T23:59:59.000Z
Proton stability is one of the most perplexing puzzles in particle physics. While the renormalizable Standard Model forbids proton decay mediating operators due to accidental global symmetries, many of its extensions introduce such dimension four, five and six operators. Furthermore, it is, in general, expected that quantum gravity only respects local gauge, or discreet, symmetries. String theory provides the arena to study particle physics in a consistent framework of perturbative quantum gravity. An appealing proposition, in this context, is that the dangerous operators are suppressed by an Abelian gauge symmetry, which is broken near the TeV scale. A viable U(1) symmetry should also be anomaly free, be family universal, and allow the generation of fermion masses via the Higgs mechanism. We discuss such U(1) symmetries that arise in quasi--realistic free fermionic heterotic--string derived models. Ensuring that the U(1) symmetry is anomaly free at the low scale requires that the Standard Model spectrum is augmented by additional states that are compatible with the charge assignments in the string models. We construct such string--inspired models and discuss some of their phenomenological implications.
Multi-Spin Strings in AdS_4*CP^3 and its ?-deformation
Jun-Bao Wu
2013-05-31T23:59:59.000Z
In this paper, we study the multi-spin string solutions in AdS_4*CP^3 and its \\beta-deformation with real \\beta. We give various explicit solutions after some general studies. Conserved charges are computed for these explicit solutions.
String theories as the adiabatic limit of Yang-Mills theory
Popov, Alexander D
2015-01-01T23:59:59.000Z
We consider Yang-Mills theory with a matrix gauge group $G$ on a direct product manifold $M=\\Sigma_2\\times H^2$, where $\\Sigma_2$ is a two-dimensional Lorentzian manifold and $H^2$ is a two-dimensional open disc with the boundary $S^1=\\partial H^2$. The Euler-Lagrange equations for the metric on $\\Sigma_2$ yield constraint equations for the Yang-Mills energy-momentum tensor. We show that in the adiabatic limit, when the metric on $H^2$ is scaled down, the Yang-Mills equations plus constraints on the energy-momentum tensor become the equations describing strings with a worldsheet $\\Sigma_2$ moving in the based loop group $\\Omega G=C^\\infty (S^1, G)/G$, where $S^1$ is the boundary $S^1=\\partial H^2$ of $H^2$. By choosing $G= R^{d-1, 1}$ and putting to zero all parameters in $\\Omega R^{d-1, 1}$ besides $R^{d-1, 1}$, we get a string moving in $R^{d-1, 1}$. If one takes $\\Sigma_2= R\\times [0,1]$ or $R\\times S^1$, one obtains equations for open or closed strings. Similarly one can get equations of string moving in ...
Electrostatics in a Schwarzschild black hole pierced by a cosmic string
B. Linet
1999-04-19T23:59:59.000Z
We explicitly determine the expression of the electrostatic potential generated by a point charge at rest in the Schwarzschild black hole pierced by a cosmic string. We can then calculate the electrostatic self-energy. From this, we find again the upper entropy bound for a charged object by employing thermodynamics of the black hole.
Exact metric for the exterior of a global string in the Brans-Dicke theory
B. Boisseau; B. Linet
1998-02-03T23:59:59.000Z
We determine in closed form the general static solution with cylindrical symmetry to the Brans-Dicke equations for an energy-momentum tensor corresponding to the one of the straight U(1) global string outside the core radius assuming that the Goldstone boson field takes its asymptotic value
String method in collective variables: Minimum free energy paths and isocommittor surfaces
Van Den Eijnden, Eric
York University, New York, New York 10012 Giovanni Ciccottid INFM and Dipartimento di Fisica in the free energy. Provided that the number of collective variables is large enough, the new techniqueString method in collective variables: Minimum free energy paths and isocommittor surfaces Luca
String Instability in Classes of Linear Time Invariant Formation Control with Limited
Duffy, Ken
of the frequency response magnitude of the transfer function mapping a disturbance to the leading vehicle along the string of the response to a disturbance to the lead vehicle. Different measures of disturbance amplification have been proposed in the literature. For example, [17] uses a frequency domain (effectively an H
Daniel Cremades; Fernando Quevedo; Aninda Sinha
2005-11-14T23:59:59.000Z
We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation. Flux-induced `warping' can provide the small slow-roll parameters needed for successful inflation. Constraints on the parameter space leading to sufficient number of e-folds, exit from inflation, density perturbations and stabilization of the Kahler modulus are investigated. The conditions are difficult to satisfy in Klebanov-Strassler throats but can be satisfied in T^3 fibrations and other generic Calabi-Yau manifolds. This requires large volume and magnetic fluxes on the D-brane. The end of inflation may or may not lead to cosmic strings depending on the original non-BPS configuration. A careful investigation of initial conditions leading to a phenomenologically viable model for inflation is carried out. The initial conditions are chosen on the basis of Sen's open string completeness conjecture. We find time symmetrical bounce solutions without initial singularities for k=1 FRW models which are correlated with an inflationary period. Singular big-bang/big-crunch solutions also exist but do not lead to inflation. There is an intriguing correlation between having an inflationary universe in 4 dimensions and 6 compact dimensions or a big-crunch singularity and decompactification.
String Theory on Thin Semiconductors: Holographic Realization of Fermi Points and Surfaces
Soo-Jong Rey
2009-11-27T23:59:59.000Z
I make a novel contact between string theory and degenerate fermion dynamics in thin semiconductors. Utilizing AdS/CFT correspondence in string theory and tunability of coupling parameters in condensed matter systems, I focus on the possibilities testing string theory from tabletop experiments. I first discuss the observation that stability of Fermi surface is classifiable according to K-theory. I then elaborate two concrete realization of Fermi surfaces of zero and two dimensions. Both are realized by complex of D3-branes and D7-branes of relative codimension 6 and 4, respectively. The setup with Fermi point models gauge dynamics of multiply stacked graphenes at half-filling. I show that string theory predicts dynamical generation of mass gap and metal-insulator quantum phase transition at zero temperature. I emphasize that conformally invariant gauge theory dynamics of the setup plays a crucial role, leading to novel conformal phase transition. The setup with Fermi surface is in collaboration with Dongsu Bak and is based on charged black hole and models relativistic Fermi liquid. We find positive evidence for this identification from both equilibrium thermodynamics at or near zero temperature and out-of-equilibrium linear response and transport properties. I argue that fluctuation of black hole horizon provides holographic realization consistent with Fermi liquid for thermodynamics and interesting departures therefrom in transport properties.
Disjunctive Partial Deduction of a Right-to-Left String-Matching Algorithm
Rosenblueth, David A.
Nacional Aut#19;onoma de M#19;exico Apdo. 20-726, 01000 M#19;exico D.F. Abstract In spite of its practical importance, the Boyer{Moore string-matching algorithm has hardly been studied in the context of partial- ants of a di#11;erent (right-to-left) algorithm, devised by Boyer and Moore, are considerably faster
Highly Scalable Algorithms for Robust String Barcoding Bhaskar DasGupta1
Mandoiu, Ion
. String barcoding is a recently introduced technique for genomic-based identification of microorganisms enable distinguisher selection based on whole genomic sequences of hundreds of microorganisms of up the applicability range to thousands of bacterial size genomes. Experimental results on both randomly generated
London Penetration Length and String Tension in SU(2) Lattice Gauge Theory
Paolo Cea; Leonardo Cosmai
1994-11-24T23:59:59.000Z
We study the distribution of the color fields due to a static quark-antiquark pair in SU(2) lattice gauge theory. We find evidence of dual Meissner effect. We put out a simple relation between the penetration length and the string tension.
Big-Bang Nucleosynthesis and Gamma-Ray Constraints on Cosmic Strings with a large Higgs condensate
H. F. Santana Mota; Mark Hindmarsh
2015-01-06T23:59:59.000Z
We consider constraints on cosmic strings from their emission of Higgs particles, in the case that the strings have a Higgs condensate with amplitude of order the string mass scale, assuming that a fraction of the energy of condensate can be turned into radiation near cusps. The injection of energy by the decaying Higgs particles affects the light element abundances predicted by standard Big-Bang Nucleosynthesis (BBN), and also contributes to the Diffuse Gamma-Ray Background (DGRB) in the universe today. We examine the two main string scenarios (Nambu-Goto and field theory), and find that the primordial Helium abundance strongly constrains the string tension and the efficiency of the emission process in the NG scenario, while the strongest BBN constraint in the FT scenario comes from the Deuterium abundance. The Fermi-LAT measurement of the DGRB constrains the field theory scenario even more strongly than previously estimated from EGRET data, requiring that the product of the string tension {\\mu} and Newton's constant G is bounded by G{\\mu} < 2.7x10^{-11}{\\beta}_{ft}^{-2}, where {\\beta}_{ft}^2 is the fraction of the strings' energy going into Higgs particles.
Dirichlet branes and nonperturbative aspects of supersymmetric string and gauge theories
Yin, Zheng
1999-05-01T23:59:59.000Z
In chapter 1 the author reviews some elements of string theory relevant to the rest of this report. He touches on both the classical, i.e. perturbative, string physics before D-branes rise to prominence, and some of the progresses they brought forth. In chapter 2 he proceeds to give an exact algebraic formulation of D-branes in curved spaces. This allows one to classify them in backgrounds of interest and study their geometric properties. He applies this formalism to string theory on Calabi-Yau and other supersymmetry preserving manifolds. Then he studies the behavior of the D-branes under mirror symmetry in chapter 3. Mirror symmetry is known to be a symmetry of string theory perturbatively. He finds evidence for its nonperturbative validity when D-branes are also considered and compute some dynamical consequences. In chapter 4 he turns to examine the consistency of curved and/or intersecting D-brane configurations. They have been used recently to extract information about the field theories that arise in certain limits. It turns out that there are potential quantum mechanical inconsistencies associated with them. What saves the day are certain subtle topological properties of D-branes. This resolution has implications for the conserved charges carried by the D-branes, which he computes for the cases studied in chapter 2. In chapter 5 he uses intersecting brane configurations to study three dimensional supersymmetric gauge theories. There is also a mirror symmetry there that, among other things, exchanges classical and quantum mechanical quantities of a (mirror) pair of theories. It has an elegant realization in term of a symmetry of string theory involving D-branes. The author employs it to study a wide class of 3d models. He also predicts new mirror pairs and unconventional 3d field theories without Lagrangian descriptions.