Utah, University of
that occur in both the gas and condensed phases. Individual steps are likely to have different activation, Brittany A. Brems, and Charles A. Wight* Center for Thermal Analysis, Department of Chemistry, Uni by thermo- gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Activation energies
Using the ProdFLOWTM Approach to Address the Myth
Siemens AG Otto-Hahn-Ring 6 81730 Munich, Germany melanie.ruhe@siemens.com Stefan Wagner Technische of the Siemens AG the new approach ProdFLOWTM* for the analysis and management of a research & development or * ProdFLOW is a registered Trademark of the Siemens AG. Permission to make digital or hard copies of all
Property:NbrProdWells | Open Energy Information
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Pfeifer, Holger
1 Complete Quantitative online Analysis of Methanol Electrooxidation Prod- ucts via Electron Impact for application in energy re- lated electrocatalysis is demonstrated using continuous methanol oxidation over
Nesnas, Nasri
.1021/np100090e |J. Nat. Prod. XXXX, XXX, 000000 NOTE pubs.acs.org/jnp Epiafzelechin from the Root Bark
May, J. Peter
MENTORING PAIRINGS APPRENTICE Graduate Undergraduate students, e-mails, and mentors. ________________________________________________________ |_Name;2 MENTORING PAIRINGS YSP Graduate students and e
Pairings on hyperelliptic curves
Balakrishnan, Jennifer; Chisholm, Sarah; Eisentraeger, Kirsten; Stange, Katherine; Teske, Edlyn
2009-01-01T23:59:59.000Z
We assemble and reorganize the recent work in the area of hyperelliptic pairings: We survey the research on constructing hyperelliptic curves suitable for pairing-based cryptography. We also showcase the hyperelliptic pairings proposed to date, and develop a unifying framework. We discuss the techniques used to optimize the pairing computation on hyperelliptic curves, and present many directions for further research.
May, J. Peter
MENTORING PAIRINGS APPRENTICE Undergraduate students, e-mails, and mentors. ________________________________________________________________________________ |_Name_(18)____________|@uchicago.edu_|_______________mentor(s)________________* *_ | | Padraic James
Chasman, R.R. [Argonne National Lab., IL (United States). Physics Div.
1996-12-31T23:59:59.000Z
In this contribution, the author mentions some features of pairing forces that are unique to nuclei and cover some areas of major interest in nuclear structure research, that involve pairing. At the level of most nuclear structure studies, nuclei are treated as consisting of two kinds of fermions (protons and neutrons) in a valence space with rather few levels. These features give rise to unique aspects of pairing forces in nuclei: (1) n-p pairing in T = 0 as well as the usual T = 1 pairing that is characteristic of like fermions; (2) a need to correct pairing calculations for the (1/N) effects that can typically be neglected in superconducting solids. An issue of current concern is the nature of the pairing interaction: several recent studies suggest a need for a density dependent form of the pairing interaction. There is a good deal of feedback between the questions of accurate calculations of pairing interactions and the form and magnitude of the pairing interaction. Finally, the authors discuss some many-body wave functions that are a generalization of the BCS wave function form, and apply them to a calculation of energy level spacings in superdeformed rotational bands.
Theiler, James P [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.
James Valles
2010-01-08T23:59:59.000Z
Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions.
First quantized pair interactions
A. F. Bennett
2014-07-01T23:59:59.000Z
The annihilation and creation operators of Quantum Field Theory presuppose a causality condition and so the theory cannot represent macroscopic entanglement. The multiple-particle parametrized Dirac wave equation can represent entanglement without recourse to a causality condition. It is shown here that the parametrized formalism can also represent pair annihilation and creation.
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
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Multiprocessor switch with selective pairing
Gara, Alan; Gschwind, Michael K; Salapura, Valentina
2014-03-11T23:59:59.000Z
System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus
Nomura, Kazumasa
2007-01-01T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of $K$-linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfies the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering ${V_i}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering ${V^*_i}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
Nuclear Resonance Fluorescence for Nuclear Materials Assay
Quiter, Brian Joseph
2010-01-01T23:59:59.000Z
tungsten for various angular ranges of brems- strahlung photon production.tungsten for various angular ranges of bremsstrahlung photon production.tungsten and lead have high densities and relative to lower-Z ma- terials, have larger pair production
Nuclear pairing: basic phenomena revisited
G. F. Bertsch
2012-03-25T23:59:59.000Z
I review the phenomena associated with pairing in nuclear physics, most prominently the ubiquitous presence of odd-even mass differences and the properties of the excitation spectra, very different for even-even and odd-A nuclei. There are also significant dynamical effects of pairing, visible in the inertias associated with nuclear rotation and large-amplitude shape deformation.
Pair extended coupled cluster doubles
Henderson, Thomas M; Scuseria, Gustavo E
2015-01-01T23:59:59.000Z
The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreoever, pEC...
Some Special Fourier Transform Pairs
Vickers, James
Some Special Fourier Transform Pairs 24.3 Introduction ' & $ % Prerequisites Before starting to . . . #12;1. Parseval's Theorem Recall from Unit 2 on Fourier Series that for a periodic signal fT (t) with complex Fourier coefficients cn(n = 0, ±1, ±2, . . .) Parseval's Theorem holds: 1 T + T 2 - T 2 f2 T (t
Tridiagonal pairs of Krawtchouk type
Ito, Tatsuro
2007-01-01T23:59:59.000Z
Let $K$ denote an algebraically closed field with characteristic 0 and let $V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$ denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has Krawtchouk type whenever the sequence $\\lbrace d-2i\\rbrace_{i=0}^d$ is a standard ordering of the eigenvalues of $A$ and a standard ordering of the eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there exists a nondegenerate symmetric bilinear form $$ on $V$ such that $= $ and $= $ for $u,v\\in V$. We show that the following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii) $A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.
The ion pairs and superconducting bosons
V. N. Minasyan
2009-02-11T23:59:59.000Z
First, it is shown that the creation of the spinless ion pairs in the lattice, which are hold by the binding with neighbor ion pairs together regarded as covalent. These ion pairs are created by the repulsive potential interaction of two ions which is bound as linear oscillator. The repulsive S-wave scattering between ion pairs and electrons is transformed to the attractive effective interaction between electrons which leads to a creation of electron pairs by a binding energy depending on the condensate fraction of ion pairs $\\frac{N_0}{N}$. In this respect, the absence of ion pairs in the condensate destroys a binding energy of electron pairs and in turn so-called superconductimg phase. As new result presented theory is that the number of the superconducting bosons is not changed in the superconducting phase.
Constraining the nuclear pairing gap with pairing vibrations M. Grasso,1
Boyer, Edmond
Constraining the nuclear pairing gap with pairing vibrations E. Khan,1 M. Grasso,1 and J. Margueron. Using the same pairing interaction in nuclear matter and in Tin nuclei, the range of densities where I. INTRODUCTION Studies on pairing effects in both nuclear matter and fi- nite nuclei have known
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomassPPPO WebsitePalms Village Resort BParticle September 11, 1997
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Galaxy pairs align with galactic filaments
Tempel, Elmo
2015-01-01T23:59:59.000Z
Context. Gravitational collapse theory and numerical simulations suggest that the velocity field within large-scale galaxy filaments is dominated by motions along the filaments. Aims. Our aim is to check whether observational data reveal any preferred orientation of galaxy pairs with respect to the underlying filaments as a result of the expectedly anisotropic velocity field. Methods. We use galaxy pairs and galaxy filaments identified from the Sloan Digital Sky Survey data. For filament extraction, we use the Bisous model that is based the marked point process technique. During the filament detection, we use the centre point of each pair instead of the positions of galaxies to avoid a built-in influence of pair orientation on the filament construction. For pairs lying within filaments (3012 cases), we calculate the angle between the line connecting galaxies of each pair and their host filament. To avoid redshift-space distortions, the angle is measured in the plain of the sky. Results. The alignment analysis...
Pairing Effects in Nuclear Fusion Reaction
Shuichiro Ebata; Takashi Nakatsukasa
2013-09-29T23:59:59.000Z
We simulate a heavy-ion collision using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) treating pairing correlation in the three-dimensional coordinate space. We apply the Cb-TDHFB to 22O+22O collision with a contact-type pairing energy functional, and compare results of Cb-TDHFB and TDHF to investigate the effects of pairing correlations in nuclear fusion. Our results seem to indicate that pairing effects do not increase the fusion cross section in this system.
MENTORING PAIRINGS APPRENTICE and SIT-INS
May, J. Peter
MENTORING PAIRINGS APPRENTICE and SIT-INS Graduate students and e-mails Name (weeks) @math Undergraduate students, e-mails, and mentors. Name (32) @uchicago.edu mentor(s) William Cole Abram abramwc serapuff Kerr, Thiyagarajan Tengren Zhang tengren85 Bou-Rabee, Putman #12;2 MENTORING PAIRINGS SESAME
Modularity of Termination Using Dependency Pairs ?
Ábrahám, Erika
Modularity of Termination Using Dependency Pairs ? Thomas Arts 1 and J¨urgen Giesl 2 1 Computer@informatik.thdarmstadt.de Abstract. The framework of dependency pairs allows automated ter mination and innermost termination proofs of this framework in order to prove termination in a modular way. Our mod ularity results significantly increase
Exact solution of the nuclear pairing problem
Alexander Volya; B. Alex Brown; Vladimir Zelevinsky
2001-02-20T23:59:59.000Z
In many applications to finite Fermi-systems, the pairing problem has to be treated exactly. We suggest a numerical method of exact solution based on SU(2) quasispin algebras and demonstrate its simplicity and practicality. We show that the treatment of binding energies with the use of the exact pairing and uncorrelated monopole contribution of other residual interactions can serve as an effective alternative to the full shell-model diagonalization in spherical nuclei. A self-consistent combination of the exactly treated pairing and Hartree-Fock method is discussed. Results for Sn isotopes indicate a good agreement with experimental data.
MENTORING PAIRINGS APPRENTICE and SIT-INS
May, J. Peter
MENTORING PAIRINGS APPRENTICE and SIT_Thiyagarajan______|____avan________| Coordinator: Michael Geline _________Undergraduate_students,_e-mails,_and_mentors.___ |_Name_(32)_____________|@uchicago.edu_|___mentor(s)_____ | | William Cole Abram | abramwc | Guillou, Morris | | Dylan
Dense QCD: Overhauser or BCS pairing?
Park, Byung-Yoon [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of) [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of); Department of Physics, Chungnam National University, Taejon 305-764, Korea (Korea, Republic of); Rho, Mannque [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of) [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of); Service de Physique Theorique, CE Saclay, 91191 Gif-sur-Yvette, (France); Wirzba, Andreas [Department of Physics and Astronomy, SUNY-Stony Brook, New York 11794 (United States) [Department of Physics and Astronomy, SUNY-Stony Brook, New York 11794 (United States); FZ Juelich, Institut fuer Kernphysik (Theorie), D-52425 Juelich, (Germany); Zahed, Ismail [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of) [School of Physics, Korea Institute for Advanced Study, Seoul 130-012, Korea (Korea, Republic of); Department of Physics and Astronomy, SUNY-Stony Brook, New York 11794 (United States)
2000-08-01T23:59:59.000Z
We discuss the Overhauser effect (particle-hole pairing) versus the BCS effect (particle-particle or hole-hole pairing) in QCD at large quark density. In weak coupling and to leading logarithm accuracy, the pairing energies can be estimated exactly. For a small number of colors, the BCS effect overtakes the Overhauser effect, while for a large number of colors the opposite takes place, in agreement with a recent renormalization group argument. In strong coupling with large pairing energies, the Overhauser effect may be dominant for any number of colors, suggesting that QCD may crystallize into an insulator at a few times nuclear matter density, a situation reminiscent of dense Skyrmions. The Overhauser effect is dominant in QCD in 1+1 dimensions, although susceptible to quantum effects. It is sensitive to temperature in all dimensions. (c) 2000 The American Physical Society.
Leonard pairs from 24 points of view
Paul Terwilliger
2004-06-28T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V\\to V$ and $A^*:V\\to V$ that satisfy both conditions below: (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is diagonal and the matrix representing $A^*$ is irreducible tridiagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A^*$ is diagonal and the matrix representing $A$ is irreducible tridiagonal. We call such a pair a {\\it Leonard pair} on $V$. Referring to the above Leonard pair, we investigate 24 bases for $V$ on which the action of $A$ and $A^*$ takes an attractive form. With respect to each of these bases, the matrices representing $A$ and $A^*$ are either diagonal, lower bidiagonal, upper bidiagonal, or tridiagonal.
Schwinger pair creation in multilayer graphene
M. A. Zubkov
2012-04-05T23:59:59.000Z
The low energy effective field model for the multilayer graphene (at ABC stacking) in external Electric field is considered. The Schwinger pair creation rate and the vacuum persistence probability are calculated using the semi - classical approach.
90 Seconds of Discovery: Frustrated Lewis Pairs
Kathmann, Shawn; Schenter, Greg; Autrey, Tom
2014-02-14T23:59:59.000Z
Hydrogen activating catalysts play an important role in producing valuable chemicals, such as biofuels and ammonia. As a part of efforts to develop the next generation of these catalysts, PNNL researchers have found potential in Frustrated Lewis Pairs.
90 Seconds of Discovery: Frustrated Lewis Pairs
Kathmann, Shawn; Schenter, Greg; Autrey, Tom
2014-07-21T23:59:59.000Z
Hydrogen activating catalysts play an important role in producing valuable chemicals, such as biofuels and ammonia. As a part of efforts to develop the next generation of these catalysts, PNNL researchers have found potential in Frustrated Lewis Pairs.
NONSMOOTH LYAPUNOV PAIRS FOR INFINITE-DIMENSIONAL ...
2010-05-27T23:59:59.000Z
Lyapunov pairs have been considered in [14,15,17,25,30] among many ... The criteria in [14,15,24,25] are given by means of the semigroup generated by.
Dual Origin of Pairing in Nuclei
A. Idini; G. Potel; F. Barranco; E. Vigezzi; R. A. Broglia
2014-04-29T23:59:59.000Z
An essentially "complete" description of the low-energy nuclear structure of the superfluid nucleus $^{120}$Sn and of its odd-$A$ neighbors is provided by the observations carried out with the help of Coulomb excitation and of one-- and of two-- particle transfer reactions, specific probes of vibrations, quasiparticle and pairing degrees of freedom respectively, and of their mutual couplings. These experimental findings are used to stringently test the predictions of a similarly "complete" description of $^{119,120,121}$Sn carried out in terms of elementary modes of excitation which, through their interweaving, melt together into effective fields, each displaying properties reflecting that of all others, there individuality resulting from the actual relative importance of each one. Its implementation is done by solving the Nambu-Gor'kov equations including, for the first time, all medium polarization effects resulting from the interweaving of quasiparticles, spin and surface vibrations, taking into account, within the framework of nuclear field theory (NFT), the variety of processes leading to self-energy, vertex and Pauli principle corrections, and to the induced pairing interaction. Theory provides an overall quantitative account of the experimental findings. From these results one can, not only obtain strong circumstantial evidence for the inevitability for the dual origin of pairing in nuclei but also, extract information which can be used at profit to quantitatively disentangle the contributions to pairing correlations in general and to the pairing gap in particular, arising from the bare and from the induced pairing interactions.
Nuclear elements in Banach Jordan pairs Ottmar Loos
Nuclear elements in Banach Jordan pairs Ottmar Loos Abstract We introduce nuclear elements in Banach Jordan pairs, generalizing the nuclear elements Jordan pairs and show that the trace form Trintroduced in [3] may be extended to the nuclear
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U.S. Energy Information Administration (EIA) Indexed Site
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U.S. Energy Information Administration (EIA) Indexed Site
Other Motor Gas Blending Components",1003,"NEWARK, NJ","NEW JERSEY",1,685,"NORWAY",41,0,0,"KINDER MORGAN ",408,"CARTERET","NJ","NEW JERSEY",1 "application...
RPT_PERIOD","R_S_NAME","LINE_NUM","PROD_CODE","PROD_NAME","PORT...
U.S. Energy Information Administration (EIA) Indexed Site
Other Motor Gas Blending Components",1003,"NEWARK, NJ","NEW JERSEY",1,685,"NORWAY",50,0,0,"IMTT ",438,"BAYONNE","NJ","NEW JERSEY",1 "applicationvnd.ms-excel","ATLANTIC...
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U.S. Energy Information Administration (EIA) Indexed Site
BANK PLC ",2,025,"Crude Oil",3201,"HONOLUPEARL, HA","HAWAII",5,150,"ARGENTINA",995,0.19,24.2,"HAWAII INDEPENDENT ENERGY ",363,"KAPOLEI","HI","HAWAII",5...
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U.S. Energy Information Administration (EIA) Indexed Site
Oil",3604,"INTER. FALLS,MN","MINNESOTA",2,260,"CANADA",117,4.06,20.9,"MERCURIA ENERGY TRADING ",4966,"GREEN PORT","TX","TEXAS",3 "applicationvnd.ms-excel","MICHIGAN...
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U.S. Energy Information Administration (EIA) Indexed Site
Oil",3604,"INTER. FALLS,MN","MINNESOTA",2,260,"CANADA",164,4.06,20.9,"MERCURIA ENERGY TRADING ",4966,"GREEN PORT","TX","TEXAS",3 "applicationvnd.ms-excel","MICHIGAN...
RPT_PERIOD","R_S_NAME","LINE_NUM","PROD_CODE","PROD_NAME","PORT...
U.S. Energy Information Administration (EIA) Indexed Site
",3,025,"Crude Oil",3402,"NOYES, MN","MINNESOTA",2,260,"CANADA",62,3.86,21.6,"MERCURIA ENERGY TRADING ",4966,"GREEN PORT","TX","TEXAS",3 "applicationvnd.ms-excel","MERCURIA...
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U.S. Energy Information Administration (EIA) Indexed Site
5,510,"Residual Fuel, Over 1.00% Sulfur",1003,"NEWARK, NJ","NEW JERSEY",1,220,"BRAZIL",11,3.41,0,,,,,," " "applicationvnd.ms-excel","AEGEAN BUNKERING USA LLC ",11,510,"Residual...
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U.S. Energy Information Administration (EIA) Indexed Site
AEGEAN BUNKERING USA LLC ",1,510,"Residual Fuel, Over 1.00% Sulfur",1601,"CHARLESTON, SC","SOUTH CAROLINA",1,260,"CANADA",38,4.11,0,,,,,," " "applicationvnd.ms-excel","AEGEAN...
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U.S. Energy Information Administration (EIA) Indexed Site
4,510,"Residual Fuel, Over 1.00% Sulfur",1003,"NEWARK, NJ","NEW JERSEY",1,260,"CANADA",100,2.19,0,,,,,," " "applicationvnd.ms-excel","AEGEAN BUNKERING USA LLC ",3,510,"Residual...
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U.S. Energy Information Administration (EIA) Indexed Site
1,510,"Residual Fuel, Over 1.00% Sulfur",1401,"NORFOLK, VA","VIRGINIA",1,220,"BRAZIL",15,3.45,0,,,,,," " "applicationvnd.ms-excel","AEGEAN BUNKERING USA LLC ",2,510,"Residual...
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AEGEAN BUNKERING USA LLC ",1,510,"Residual Fuel, Over 1.00% Sulfur",1003,"NEWARK, NJ","NEW JERSEY",1,260,"CANADA",70,5.13,0,,,,,," " "applicationvnd.ms-excel","AEGEAN BUNKERING...
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U.S. Energy Information Administration (EIA) Indexed Site
" "applicationvnd.ms-excel","AEGEAN BUNKERING USA LLC ",2,510,"Residual Fuel, Over 1.00% Sulfur",1003,"NEWARK, NJ","NEW JERSEY",1,260,"CANADA",93,2.63,0,,,,,," "...
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U.S. Energy Information Administration (EIA) Indexed Site
201,"SPRAGUE ENERGY CORP",1,461,"DIST, < 0.05% SUL (DOM.)",0131,"PORTSMOUTH, NH","NH",100,260,"CANADA",114,0,0 0201,"SPRAGUE ENERGY CORP",2,461,"DIST, < 0.05% SUL...
Pairing, pseudogap and Fermi arcs in cuprates
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kaminski, Adam; Gu, Genda; Kondo, Takeshi; Takeuchi, Tsunehiro
2014-10-31T23:59:59.000Z
We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmorecreates artificial Fermi arcs for Tc pair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.less
Isominkowskian theory of Cooper Pairs in superconductors
Animalu, A.O.E. [Univ. of Nigeria, Nsukka (Nigeria)
1993-10-01T23:59:59.000Z
Via the use of Santilli`s isominkowskian space, the author presents a relativistic extension of the author`s recent treatment of the Cooper Pair in superconductivity based on the Lie-isotopic lifting of quantum mechanics known as Hadronic Mechanics. The isominkowskian treatment reduces the solution of the eiganvalue problem for the quasiparticle energy spectrum to a geometric problem of specifying the metric of the isominkowskian space inside the pair in various models of ordinary high T{sub c} superconductors. The use of an intriguing realization of the metric due to Dirac reduces the dimensionality of the interior space to two yielding a spin mutation from 1/2 to zero inside a Cooper pair in two-band BCS and Hubbard models. 12 refs.
Thermodynamics of pairing transition in hot nuclei
Lang Liu; Zhen-Hua Zhang; Peng-Wei Zhao
2014-12-16T23:59:59.000Z
The pairing correlations in hot nuclei $^{162}$Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The heat capacities $C_V$ are evaluated in the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. A S-shaped heat capacity curve, which agrees qualitatively with the experimental data, has been obtained and analyzed in details. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.
Thermodynamics of pairing in mesoscopic systems
Tony Sumaryada; Alexander Volya
2007-06-12T23:59:59.000Z
Using numerical and analytical methods implemented for different models we conduct a systematic study of thermodynamic properties of pairing correlation in mesoscopic nuclear systems. Various quantities are calculated and analyzed using the exact solution of pairing. An in-depth comparison of canonical, grand canonical, and microcanonical ensemble is conducted. The nature of the pairing phase transition in a small system is of a particular interest. We discuss the onset of discontinuity in the thermodynamic variables, fluctuations, and evolution of zeros of the canonical and grand canonical partition functions in the complex plane. The behavior of the Invariant Correlational Entropy is also studied in the transitional region of interest. The change in the character of the phase transition due to the presence of magnetic field is discussed along with studies of superconducting thermodynamics.
Schwinger Pair Production in Pulsed Electric Fields
Sang Pyo Kim; Hyung Won Lee; Remo Ruffini
2012-07-22T23:59:59.000Z
We numerically investigate the temporal behavior and the structure of longitudinal momentum spectrum and the field polarity effect on pair production in pulsed electric fields in scalar quantum electrodynamics (QED). Using the evolution operator expressed in terms of the particle and antiparticle operators, we find the exact quantum states under the influence of electric pulses and measure the number of pairs of the Minkowski particle and antiparticle. The number of pairs, depending on the configuration of electric pulses, exhibits rich structures in the longitudinal momentum spectrum and undergoes diverse dynamical behaviors at the onset of the interaction but always either converges to a momentum-dependent constant or oscillates around a momentum-dependent time average after the completion of fields.
Yoshiaki Tsujimoto; Yukihiro Sugiura; Makoto Ando; Daisuke Katsuse; Rikizo Ikuta; Takashi Yamamoto; Masato Koashi; Nobuyuki Imoto
2015-03-10T23:59:59.000Z
We experimentally demonstrated entanglement extraction scheme by using photons at the telecommunication band for optical-fiber-based quantum communications. We generated two pairs of non-degenerate polarization entangled photons at 780~nm and 1551~nm by spontaneous parametric down-conversion and distributed the two photons at 1551~nm through a collective phase damping channel which gives the same amount of random phase shift on the two photons. Through local operation and classical communication, we extracted an entangled photon pair from two phase-disturbed photon pairs. An observed fidelity of the extracted photon pair to a maximally entangled photon pair was 0.73 $\\pm$ 0.07 which clearly shows the recovery of entanglement.
Subthreshold pair production in short laser pulses
T. Nousch; D. Seipt; B. Kampfer; A. I. Titov
2012-06-01T23:59:59.000Z
The $e^+e^-$ pair production by a probe photon traversing a linearly polarized laser pulse is treated as generalized nonlinear Breit-Wheeler process. For short laser pulses with very few oscillations of the electromagnetic field we find below the perturbative weak-field threshold $\\sqrt{s} = 2m$ a similar enhancement of the pair production rate as for circular polarization. The strong subthreshold enhancement is traced back to the finite bandwidth of the laser pulse. A folding model is developed which accounts for the interplay of the frequency spectrum and the intensity distribution in the course of the pulse.
Photon pair generation in birefringent optical fibers
Brian J. Smith; P. Mahou; Offir Cohen; J. S. Lundeen; I. A. Walmsley
2010-02-09T23:59:59.000Z
We study both experimentally and theoretically the generation of photon pairs by spontaneous four-wave mixing (SFWM) in standard birefringent optical fibers. The ability to produce a range of two-photon spectral states, from highly correlated (entangled) to completely factorable, by means of cross-polarized birefringent phase matching, is explored. A simple model is developed to predict the spectral state of the photon pair which shows how this can be adjusted by choosing the appropriate pump bandwidth, fiber length and birefringence. Spontaneous Raman scattering is modeled to determine the tradeoff between SFWM and background Raman noise, and the predicted results are shown to agree with experimental data.
Single top and top pair production
Nikolaos Kidonakis
2012-12-12T23:59:59.000Z
I present results for single-top and top-pair production at the LHC and the Tevatron. Higher-order two-loop corrections are used to achieve NNLL resummation, which is then used to derive NNLO soft-gluon corrections. Results are presented for total cross sections, top transverse momentum distributions, and top rapidity distributions. All results are in excellent agreement with data from the LHC and the Tevatron. I also clarify the differences between various methods in top-pair production and their relation to exact NNLO results.
Quantum Key Distribution with Qubit Pairs
Mohd Asad Siddiqui; Tabish Qureshi
2014-07-17T23:59:59.000Z
We propose a new Quantum Key Distribution method in which Alice sends pairs of qubits to Bob, each in one of four possible states. Bob uses one qubit to generate a secure key and the other to generate an auxiliary key. For each pair he randomly decides which qubit to use for which key. The auxiliary key has to be added to Bob's secure key in order to match Alice's secure key. This scheme provides an additional layer of security over the standard BB84 protocol.
EFFECT OF JOINT AUDITOR PAIR ON CONSERVATISM
Paris-Sud XI, Université de
1 EFFECT OF JOINT AUDITOR PAIR ON CONSERVATISM: EVIDENCE FROM IMPAIRMENT TESTS Gerald Lobo's (1997) measure of conservatism, are more likely to book impairments when operating performance is low requiring joint audit to improve audit quality. Mots clés : Co-commissariat Reconnaissance adéquate des
Abstract polymer models with general pair interactions
Aldo Procacci
2008-11-26T23:59:59.000Z
A convergence criterion of cluster expansion is presented in the case of an abstract polymer system with general pair interactions (i.e. not necessarily hard core or repulsive). As a concrete example, the low temperature disordered phase of the BEG model with infinite range interactions, decaying polynomially as $1/r^{d+\\lambda}$ with $\\lambda>0$, is studied.
COOPER PAIR TRANSISTOR IN A TUNABLE ENVIRONMENT
Haviland, David
COOPER PAIR TRANSISTOR IN A TUNABLE ENVIRONMENT S. Corlevi, W. Guichard, and D. B. Haviland* 1 measurements of the CPT, which are performed in a low impedance environment, the charging effects are observed as gate voltage modulation of the critical current. However, in a high impedance environment, a Coulomb
Improved Modular Termination Proofs Using Dependency Pairs
Kobbelt, Leif
Improved Modular Termination Proofs Using Dependency Pairs Ren??e Thiemann, J?urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by wellfounded orders. However, proving innermost termination is considerably easier than
Improved Modular Termination Proofs Using Dependency Pairs #
Ábrahám, Erika
Improved Modular Termination Proofs Using Dependency Pairs # Ren??e Thiemann, J?urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by wellfounded orders. However, proving innermost termination is considerably easier than
Improved Modular Termination Proofs Using Dependency Pairs
Middeldorp, Aart
Improved Modular Termination Proofs Using Dependency Pairs Ren´e Thiemann, J¨urgen Giesl, Peter) termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by well-founded orders. However, proving innermost termination is considerably easier than
Resonant tunneling of fluctuation Cooper pairs
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.
2015-02-09T23:59:59.000Z
Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool formoredirect measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.less
Pair densities in density functional theory
Chen, Huajie
2015-01-01T23:59:59.000Z
The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...
Graduate Student Mentoring and Degree Timeline Pairing Students with Mentors
Hill, Wendell T.
Graduate Student Mentoring and Degree Timeline Pairing Students with Mentors A successful mentoring program depends upon the quality of the mentor-student pairing. In order to maximize the probability of a successful pairing, the mentor and mentoring team selection process will be as follows: 1. Designation
Method for sequencing DNA base pairs
Sessler, Andrew M. (Oakland, CA); Dawson, John (Pacific Palisades, CA)
1993-01-01T23:59:59.000Z
The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source.
Paired Straight Hearth Furnace | 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'tOrigin of Contamination in235-1 Termoelectrica U.SPRESS FACTBiofuels1of Page ThisnewPaired
Photoproduction of a ??Pair and Transversity GPDs
M. El Beiyad; B. Pire; L. Szymanowski; S. Wallon
2010-07-16T23:59:59.000Z
We demonstrate that the chiral-odd transversity generalized parton distributions (GPDs) of the nucleon can be accessed through the exclusive photoproduction process gamma + N -> pi + rho + N', in the kinematics where the meson pair has a large invariant mass and the final nucleon has a small transverse momentum, provided the vector meson is produced in a transversely polarized state. We calculate perturbatively the scattering amplitude at leading order in alpha_s: We build a simple model for the dominant transversity GPD HT (x; chi; t) based on the concept of double distribution. Counting rates estimates show that the experiment looks feasible with the real photon beam characteristics expected at JLab@12 GeV, in low Q2 leptoproduction at Jlab@12 GeV and in the COMPASS experiment.
Pair Correlation Function of Wilson Loops
S. Chaudhuri; Y. Chen; E. Novak
2000-02-02T23:59:59.000Z
We give a path integral prescription for the pair correlation function of Wilson loops lying in the worldvolume of Dbranes in the bosonic open and closed string theory. The results can be applied both in ordinary flat spacetime in the critical dimension d or in the presence of a generic background for the Liouville field. We compute the potential between heavy nonrelativistic sources in an abelian gauge theory in relative collinear motion with velocity v = tanh(u), probing length scales down to r_min^2 = 2 \\pi \\alpha' u. We predict a universal -(d-2)/r static interaction at short distances. We show that the velocity dependent corrections to the short distance potential in the bosonic string take the form of an infinite power series in the dimensionless variables z = r_min^2/r^2, uz/\\pi, and u^2.
On the polar cap cascade pair multiplicity of young pulsars
Timokhin, A N
2015-01-01T23:59:59.000Z
We study the efficiency of pair production in polar caps of young pulsars under a variety of conditions to estimate the maximum possible multiplicity of pair plasma in pulsar magnetospheres. We develop a semi-analytic model for calculation of cascade multiplicity which allows efficient exploration of the parameter space and corroborate it with direct numerical simulations. Pair creation processes are considered separately from particle acceleration in order to assess different factors affecting cascade efficiency, with acceleration of primary particles described by recent self-consistent non-stationary model of pair cascades. We argue that the most efficient cascades operate in the curvature radiation/synchrotron regime, the maximum multiplicity of pair plasma in pulsar magnetospheres is ~few x 10^5. The multiplicity of pair plasma in magnetospheres of young energetic pulsars weakly depends on the strength of the magnetic field and the radius of curvature of magnetic field lines and has a stronger dependence ...
Proton-neutron pairing correlations in the nuclear shell model
Lei Yang; S. Pittel; B. Thakur; N. Sandulescu; A. Poves; Yu-Min Zhao
2010-06-16T23:59:59.000Z
A shell-model study of proton-neutron pairing in f - p shell nuclei using a parametrized hamiltonian that includes deformation and spin-orbit effects as well as isoscalar and isovector pairing is reported. By working in a shell-model framework we are able to assess the role of the various modes of proton-neutron pairing in the presence of nuclear deformation without violating symmetries. Results are presented for $^{44}$Ti, $^{46}$Ti and $^{48}$Cr.
Theoretical overview on top pair production and single top production
Stefan Weinzierl
2012-01-19T23:59:59.000Z
In this talk I will give an overview on theoretical aspects of top quark physics. The focus lies on top pair production and single top production.
A Bell pair in a generic random matrix environment
Carlos Pineda; Thomas H. Seligman
2006-05-18T23:59:59.000Z
Two non-interacting qubits are coupled to an environment. Both coupling and environment are represented by random matrix ensembles. The initial state of the pair is a Bell state, though we also consider arbitrary pure states. Decoherence of the pair is evaluated analytically in terms of purity; Monte Carlo calculations confirm these results and also yield the concurrence of the pair. Entanglement within the pair accelerates decoherence. Numerics display the relation between concurrence and purity known for Werner states, allowing us to give a formula for concurrence decay.
associative pairing enhances: Topics by E-print Network
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design rules... Cowen, Nicholas L. 2010-07-14 22 Associated Production of Neutral Higgs Boson with Squark Pair in the Minimal Supersymmetric Standard Model with Explicit CP...
Pair correlations in crystalline solid solutions
Ice, G.E.; Sparks, C.J. [Oak Ridge National Lab., TN (United States); Shaffer, L. [Anderson Univ., IN (United States). Dept. of Physics; Zschack, P. [Oak Ridge Institute of Science and Education, TN (United States)
1994-06-01T23:59:59.000Z
Recent measurements of pair correlations in metallic solid solutions challenge simple models of atomic size in alloy structure. These measurements take advantage of intense and tunable synchrotron X radiation to control the x-ray scattering contrast between atoms in a solid solution. For binary alloys with elements nearby in the periodic table it is possible to tune the x-ray energy near the K edge so that the scattering contrast varies from near zero to {plus_minus}5 electron units. Even larger contrast variation is possible near L edges or with complementary x-ray and neutron diffraction data sets. With adjusted scattering contrast it is possible to measure short-range-order (SRO), even in alloys with elements nearby in the periodic table. It is also possible to detect chemically-specific static displacements of {plus_minus}0.001 {angstrom} or less and with fewer assumptions than with previous experimental methods. We compare the measured chemically-specific static displacements in Fe{sub 22.5}Ni{sub 77.5} and Cr{sub 47}Fe{sub 53} with previous models and with the results of other experiments.
Tridiagonal pairs of $q$-Racah type
Ito, Tatsuro
2008-01-01T23:59:59.000Z
Let $K$ denote an algebraically closed field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
How to sharpen a tridiagonal pair
Ito, Tatsuro
2008-01-01T23:59:59.000Z
Let $\\F$ denote a field and let $V$ denote a vector space over $\\F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
A classification of sharp tridiagonal pairs
Ito, Tatsuro; Terwilliger, Paul
2010-01-01T23:59:59.000Z
Let $F$ denote a field and let $V$ denote a vector space over $F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
On the shape of a tridiagonal pair
Nomura, Kazumasa
2009-01-01T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\lbrace V_i\\rbrace_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\lbrace V^*_i\\rbrace_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
The structure of a tridiagonal pair
Nomura, Kazumasa
2008-01-01T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_i + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_i + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv)there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
Tridiagonal pairs and the $\\mu$-conjecture
Nomura, Kazumasa
2009-01-01T23:59:59.000Z
Let $F$ denote a field and let $V$ denote a vector space over $F$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
Towards a classification of the tridiagonal pairs
Nomura, Kazumasa
2008-01-01T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. Let $End(V)$ denote the $K$-algebra consisting of all $K$-linear transformations from $V$ to $V$. We consider a pair $A,A^* \\in End(V)$ that satisfy (i)--(iv) below: (i) Each of $A,A^*$ is diagonalizable. (ii) There exists an ordering $\\{V_i\\}_{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$. (iii) There exists an ordering $\\{V^*_i\\}_{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$. (iv) There is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
Pairing-induced speedup of nuclear spontaneous fission
Jhilam Sadhukhan; J. Dobaczewski; W. Nazarewicz; J. A. Sheikh; A. Baran
2014-10-06T23:59:59.000Z
Collective inertia is strongly influenced at the level crossing at which quantum system changes diabatically its microscopic configuration. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of those configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of $^{264}$Fm and $^{240}$Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM$^*$ and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of $^{264}$Fm, where the effect of triaxiality on the fission barrier is large, the geometry of fission pathway in the space of shape degrees of freedom is weakly impacted by pairing. This is not the case for $^{240}$Pu where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. Consequently, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.
An interatomic pair potential for cadmium selenide Eran Rabani
Rabani, Eran
in all three crystal structures: wurtzite, zinc blende, and rocksalt. Using the new pair potential we have studied the pressure-induced phase transition from the fourfold-coordinate wurtzite structure for wurtzite cadmium selenide.6 In this paper we derive a set of interatomic pair poten- tials for cadmium
ON WAVELETS INTERPOLATED FROM A PAIR OF WAVELET SETS
Speegle, Darrin
ON WAVELETS INTERPOLATED FROM A PAIR OF WAVELET SETS Ziemowit Rzeszotnik and Darrin Speegle September 1, 2000 Abstract. We show that any wavelet, with the support of its Fourier transform small enough, can be interpolated from a pair of wavelet sets. The interpolation procedure, which was introduced
MENTORING PAIRINGS Graduate students and e-mails
May, J. Peter
MENTORING PAIRINGS APPRENTICE Graduate students and e-mails Name @math.uchicago.edu Mohammed Undergraduate students, e-mails, and mentors. Name (18) @uchicago.edu mentor(s) Padraic James Bartlett padraic jonathan Ben Lee and Wei Ren 1 #12;2 MENTORING PAIRINGS YSP Graduate students and e-mails Name @math
MENTORING PAIRINGS (plus others with mentors in common)
May, J. Peter
MENTORING PAIRINGS APPRENTICE (plus others with mentors in common) Graduate students and e-mails, and mentors. (All e-mails are @midway.uchicago.edu.) Philip Ascher pa7 Fowler, Scheels, and Iyer Emil Bojanov yuc Fowler, Scheels, and Iyer 1 #12;2 MENTORING PAIRINGS YSP (plus others with mentors in common
MENTORING PAIRINGS Graduate students and e-mails
May, J. Peter
MENTORING PAIRINGS APPRENTICE Graduate students and e-mails Name @math.uchicago.edu Kate Ponto-mails, and mentors. Name (24) e-mail mentor(s) Bargar, Emily ebargar@uchicago.edu Booth Behr, Piotr S. pbehr-INS Norton, Emily brntnrtn@uchicago.edu Ponto Rezvi, Sara arsinoe@uchicago.edu Ponto #12;2 MENTORING PAIRINGS
Computing local p-adic height pairings on hyperelliptic curves
Balakrishnan, Jennifer S
2010-01-01T23:59:59.000Z
We describe an algorithm to compute the local component at p of the Coleman-Gross p-adic height pairing on divisors on hyperelliptic curves. As the height pairing is given in terms of a Coleman integral, we also provide new techniques to evaluate Coleman integrals of meromorphic differentials and present our algorithms as implemented in Sage.
LCPHSM2004005 Study of Higgs Boson Pair Production at
LCPHSM2004005 March 2004 Study of Higgs Boson Pair Production at Linear Collider K. Desch a , TV for the measurement of the neutral Higgs boson properties within the framework of the MSSM. The process of associated Higgs boson production with subsequent decays of Higgs bosons into bquark and #lepton pairs
Pair Production of Topological anti de Sitter Black Holes
R. B. Mann
1996-07-28T23:59:59.000Z
The pair creation of black holes with event horizons of non-trivial topology is described. The spacetimes are all limiting cases of the cosmological $C$ metric. They are generalizations of the $(2+1)$ dimensional black hole and have asymptotically anti de Sitter behaviour. Domain walls instantons can mediate their pair creation for a wide range of mass and charge.
Density-matrix functionals for pairing in mesoscopic superconductors
Denis Lacroix; Guillaume Hupin
2010-09-03T23:59:59.000Z
A functional theory based on single-particle occupation numbers is developed for pairing. This functional, that generalizes the BCS approach, directly incorporates corrections due to particle number conservation. The functional is benchmarked with the pairing Hamiltonian and reproduces perfectly the energy for any particle number and coupling.
Liquid pair correlations in four spatial dimensions: Theory versus simulation
M. Heinen; J. Horbach; H. Lwen
2014-11-06T23:59:59.000Z
Using liquid integral equation theory, we calculate the pair correlations of particles that interact via a smooth repulsive pair potential in d = 4 spatial dimensions. We discuss the performance of different closures for the Ornstein-Zernike equation, by comparing the results to computer simulation data. Our results are of relevance to understand crystal and glass formation in high-dimensional systems.
Pairing-induced speedup of nuclear spontaneous fission
Sadhukhan, Jhilam; Nazarewicz, W; Sheikh, J A; Baran, A
2014-01-01T23:59:59.000Z
Collective inertia is strongly influenced at the level crossing at which quantum system changes diabatically its microscopic configuration. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of those configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of $^{264}$Fm and $^{240}$Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM$^*$ and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action princip...
Semiclassical pair production rate for rotating electric fields
Eckhard Strobel; She-Sheng Xue
2015-02-09T23:59:59.000Z
We semiclassically investigate Schwinger pair production for pulsed rotating electric fields depending on time. To do so we solve the Dirac equation for two-component fields in a WKB-like approximation. The result shows that for two-component fields the spin distribution of produced pairs is generally not $1:1$. As a result the pair creation rates of spinor and scalar quantum electro dynamics (QED) are different even for one pair of turning points. For rotating electric fields the pair creation rate is dominated by particles with a specific spin depending on the sense of rotation for a certain range of pulse lengths and frequencies. We present an analytical solution for the momentum spectrum of the constant rotating field. We find interference effects not only in the momentum spectrum but also in the total particle number of rotating electric fields.
Relativistic tunneling picture of electron-positron pair creation
Anton Wllert; Michael Klaiber; Heiko Bauke; Christoph H. Keitel
2015-03-19T23:59:59.000Z
The common tunneling picture of electron-positron pair creation in a strong electric field is generalized to pair creation in combined crossed electric and magnetic fields. This enhanced picture, being symmetric for electrons and positrons, is formulated in a gauge-invariant and Lorentz-invariant manner for quasistatic fields. It may be used to infer qualitative features of the pair creation process. In particular, it allows for an intuitive interpretation of how the presence of a magnetic field modifies and, in particular cases, even enhances pair creation. The creation of electrons and positrons from the vacuum may be assisted by an energetic photon, which can also be incorporated into this picture of pair creation.
Leonard pairs and the q-Racah polynomials
Paul Terwilliger
2008-07-24T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider an ordered pair of linear transformations $A:V\\to V$ and $A^*:V\\to V$ that satisfy conditions (i), (ii) below. (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is irreducible tridiagonal and the matrix representing $A^*$ is diagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A$ is diagonal and the matrix representing $A^*$ is irreducible tridiagonal. We call such a pair a {\\it Leonard pair} on $V$. We discuss a correspondence between Leonard pairs and a class of orthogonal polynomials consisting of the $q$-Racah polynomials and some related polynomials of the Askey scheme. For the polynomials in this class we obtain the 3-term recurrence, difference equation, Askey-Wilson duality, and orthogonality in a uniform manner using the corresponding Leonard pair.
Validity of pair truncations with effective interaction in Ca isotopes
Lei, Y.; Xu, Z. Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda ku, Tokyo 102-0091 (Japan)
2010-09-15T23:59:59.000Z
Using the GXPF1A interaction for the pf shell nuclei, we calculate energy levels and E2 transition rates for the semimagic nuclei {sup 43-46}Ca within both the exact shell-model space and a number of subspaces constructed using collective nucleon pairs. We present explicitly the overlaps between wave functions of low-lying states obtained from shell-model calculations and those obtained using truncated nucleon-pair subspaces. These examples are used as touchstones of pair approximations.
Pairs Emission in a Uniform Background Field: an Algebraic Approach
Roberto Soldati
2011-06-23T23:59:59.000Z
A fully algebraic general approach is developed to treat the pairs emission and absorption in the presence of some uniform external background field. In particular, it is shown that the pairs production and annihilation operators, together with the pairs number operator, do actually fulfill the SU(2) functional Lie algebra. As an example of application, the celebrated Schwinger formula is consistently and nicely recovered, within this novel approach, for a Dirac spinor field in the presence of a constant and homogeneous electric field in four spacetime dimensions.
pp: 121 (col.fig.: Nil) PROD. TYPE: COM
Avignon et des Pays de Vaucluse, Université de
regime; poroelasticity; matrix19 conditioning 1. INTRODUCTION21 The study of wave propagation in porous-MESGOUEZ contaminating water saturated sites, oil-filled reservoirs, seafloor, air saturated concrete or sound1 absorbing MHz.5 On the microscopic spatial scale a porous material is a medium that presents a solid part
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Macro-coherent two photon and radiative neutrino pair emission
M. Yoshimura; C. Ohae; A. Fukumi; K. Nakajima; I. Nakano; H. Nanjo; N. Sasao
2008-05-14T23:59:59.000Z
We discuss a possibility of detecting a coherent photon pair emission and related radiative neutrino pair emission from excited atoms. It is shown that atoms of lambda- and ladder-type three level system placed in a pencil-like cylinder give a back to back emission of two photons of equal energy $\\Delta/2$, sharply peaked with a width $\\propto $ 1/(target size) and well collimated along the cylinder axis. This process has a measurable rate $\\propto$ (target number density) $^2 \\times$ target volume, while a broader spectral feature of one-photon distribution separated by (mass sum of a neutrino pair)$^2/(2\\Delta)$ from the two photon peak may arise from radiative neutrino pair emission, with a much smaller rate.
Polarization operator approach to pair creation in short laser pulses
Meuren, Sebastian; Keitel, Christoph H; Di Piazza, Antonino
2014-01-01T23:59:59.000Z
We investigate the nonlinear Breit-Wheeler process inside short laser pulses, i.e. the creation of an electron-positron pair induced by a gamma photon inside a plane-wave background field. To obtain the total pair-creation probability we verify (to leading-order) the cutting rule for the polarization operator in the realm of strong-field QED by an explicit calculation. Furthermore, a double-integral representation for the leading-order contribution to the field-dependent part of the polarization operator is derived. The combination of both results yields a compact expression for the total pair-creation probability inside an arbitrary plane-wave background field. It is shown numerically that with presently available technology pair-creation probabilities of the order of ten percent could be reached for a single gamma photon.
Visualizing the Optical Interaction Tensor of a Gold Nanoparticle Pair
Novotny, Lukas
Visualizing the Optical Interaction Tensor of a Gold Nanoparticle Pair Bradley Deutsch, Rainer Hillenbrand,, and Lukas Novotny*, Institute of Optics, University of Rochester, Rochester, New York 14627, Basque Foundation for Science, 48011 Bilbao, Spain ABSTRACT The control of optical fields
QSO pairs {\\it across} Active galaxies: Evidence of Blueshifts?
D. Basu
2007-01-08T23:59:59.000Z
Several QSO pairs have been reported and their redshifts determined, where the two objects in each pair are located {\\it across} an active galaxy. The usually accepted explanation of such occurrences is that the pair is ejected from the active galaxy. Currebtly interpreted redshifted spectra for both the QSOs imply that both the objects are receding from the observer. However, ejection can occur towards and away from the observer with equal probability. We argue that for a system with two QSOs {\\it across} the parent galaxy, ejection should have occurred in opposite directions, whereby one object will be approaching us and the other will be receding from us. The former would be exhibiting a blueshifted spectrum. We analyse here a sample of four such pairs and show that the observed spectrum of one QSO in each pair can be interpreted as blueshifted. The other exhibits the ususal redshifted spectrum.A scenario based on the 'sling-shot' mechanism of ejection is presented to explain the ocurrences of the pairs in opposite sides of the active galaxies moving in opposite durections.
On magnon mediated Cooper pair formation in ferromagnetic superconductors
Kar, Rakesh; Paul, Bikash Chandra [Department of Physics, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India); Goswami, Tamal; Misra, Anirban, E-mail: anirbanmisra@yahoo.com [Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal (India)
2014-08-15T23:59:59.000Z
Identification of pairing mechanism leading to ferromagnetic superconductivity is one of the most challenging issues in condensed matter physics. Although different models have been proposed to explain this phenomenon, a quantitative understanding about this pairing is yet to be achieved. Using the localized-itinerant model, we find that in ferromagnetic superconducting materials both triplet pairing and singlet pairing of electrons are possible through magnon exchange depending upon whether the Debye cut off frequency of magnons is greater or lesser than the Hund's coupling (J) multiplied by average spin (S) per site. Taking into account the repulsive interaction due to the existence of paramagnons, we also find an expression for effective interaction potential between a pair of electrons with opposite spins. We apply the developed formalism in case of UGe{sub 2} and URhGe. The condition of singlet pairing is found to be fulfilled in these cases, as was previously envisaged by Suhl [Suhl, Phys. Rev. Lett. 87, 167007 (2001)]. We compute the critical temperatures of URhGe at ambient pressure and of UGe{sub 2} under different pressures for the first time through BCS equation. Thus, this work outlines a very simple way to evaluate critical temperature in case of a superconducting system. A close match with the available experimental results strongly supports our theoretical treatment.
Observer dependence of bubble nucleation and Schwinger pair production
Garriga, Jaume [Departament de Fsica Fonamental i Institut de Cincies del Cosmos, Universitat de Barcelona, Mart i Franqus 1, 08028 Barcelona (Spain); Kanno, Sugumi; Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States); Sasaki, Misao [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Soda, Jiro, E-mail: jaume.garriga@ub.edu, E-mail: sugumi@cosmos.phy.tufts.edu, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: jiro@tap.scphys.kyoto-u.ac.jp, E-mail: vilenkin@cosmos.phy.tufts.edu [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)
2012-12-01T23:59:59.000Z
Pair production in a constant electric field is closely analogous to bubble nucleation in a false vacuum. The classical trajectories of the pairs are Lorentz invariant, but it appears that this invariance should be broken by the nucleation process. Here, we use a model detector, consisting of other particles interacting with the pairs, to investigate how pair production is seen by different Lorentzian observers. We focus on the idealized situation where a constant external electric field is present for an infinitely long time, and we consider the in-vacuum state for a charged scalar field that describes the nucleating pairs. The in-vacuum is defined in terms of modes which are positive frequency in the remote past. Even though the construction uses a particular reference frame and a gauge where the vector potential is time dependent, we show explicitly that the resulting quantum state is Lorentz invariant. We then introduce a ''detector'' particle which interacts with the nucleated pairs, and show that all Lorentzian observers will see the particles and antiparticles nucleating preferentially at rest in the detector's rest frame. Similar conclusions are expected to apply to bubble nucleation in a sufficiently long lived vacuum. We also comment on certain unphysical aspects of the Lorentz invariant in-vacuum, associated with the fact that it contains an infinite density of particles. This can be easily remedied by considering Lorentz breaking initial conditions.
Formation of Cooper pairs as a consequence of exchange interaction
Stanislav Dolgopolov
2015-04-13T23:59:59.000Z
The pairing of two electrons with antiparallel spins may minimize the energy of each of the paired electrons. Thus the exchange interaction and the Pauli Exclusion Principle cause a bond between two electrons in a crystal. This can be proved analyzing the energy of each conduction electron in the field of a crystal on assumption that all other kinds of magnetic spin ordering in the crystal are weak. The superconductivity in a metallic crystal occurs only if conduction electrons before the pairing are put closely on the Fermi surface in the momentum space. The motion of conduction electrons in the crystal may disturb the formation of Cooper pairs, because the kinetic energy of the motion is usually much larger than the energy gap of superconductor. The conduction electrons as standing waves have a zero momentum, hence their momentums are synchronous; consequently the formation of Cooper pairs is more probable than in case of electrons with nonzero momentums. The total momentum of the pair of two electrons as standing waves is zero.
Using Disorder to Study How Electrons Pair in Iron-Based Superconducto...
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Using Disorder to Study How Electrons Pair in Iron-Based Superconductors Researchers introduced disorder to test electron pairing in iron-based superconductors and produced...
Polarization operator approach to pair creation in short laser pulses
Sebastian Meuren; Karen Z. Hatsagortsyan; Christoph H. Keitel; Antonino Di Piazza
2015-01-28T23:59:59.000Z
Short-pulse effects are investigated for the nonlinear Breit-Wheeler process, i.e. the production of an electron-positron pair induced by a gamma photon inside an intense plane-wave laser pulse. To obtain the total pair-creation probability we verify (to leading-order) the cutting rule for the polarization operator in the realm of strong-field QED by an explicit calculation. Using a double-integral representation for the leading-order contribution to the polarization operator, compact expressions for the total pair-creation probability inside an arbitrary plane-wave background field are derived. Correspondingly, the photon wave function including leading-order radiative corrections in the laser field is obtained via the Schwinger-Dyson equation in the quasistatic approximation. Moreover, the influence of the carrier-envelope phase and of the laser pulse shape on the total pair-creation probability in a linearly polarized laser pulse is investigated, and the validity of the (local) constant-crossed field approximation analyzed. It is shown that with presently available technology pair-creation probabilities of the order of ten percent could be reached for a single gamma photon.
Isovector pairing collective motion: Generator-coordinate-method approach
Kyotoku, M.; Chen, H.
1987-09-01T23:59:59.000Z
Isovector pairing collective motion is treated by means of the generator coordinate method. In this scheme, the isospin and number projection is performed analytically by the recognition of symmetry properties in the generalized Bardeen-Cooper-Schrieffer wave functions. Among the results obtained, our generator-coordinate-method values of energy and spectroscopic amplitude are shown to be comparable to those of shell model calculations. This is indeed encouraging, especially in view of the fact that they were reached using a simple approximation. The great simplicity of the present method, as compared with earlier complicated versions, suggests that they might prove useful in the study of isovector pairing collective states which are strongly populated by pair transfer reactions in medium weight nuclei.
Repulsive aspects of pairing correlation in nuclear fusion reaction
Ebata, Shuichiro
2014-01-01T23:59:59.000Z
Numerical simulation on nuclear collisions are performed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory (Cb-TDHFB) in the three-dimensional coordinate space. Comparing results of the Cb-TDHFB and the conventional time-dependent Hartree-Fock (TDHF) calculations, we study effects of the pairing correlation on fusion reaction of $^{22}$O+$^{22}$O, $^{52}$Ca+$^{52}$Ca, and $^{22}$O+$^{52}$Ca, using the Skyrme SkM$^*$ functional and a contact-type pairing energy functional. Although current results are yet preliminary, they may suggest that the pairing correlation could hinder the fusion probability at energies in the vicinity of the Coulomb barrier height. We also perform a calculation for heavier nuclei, $^{96}$Zn+$^{124}$Sn, which seems to suggest a similar hindrance effect.
Rotation Rate of Particle Pairs in Homogeneous Isotropic Turbulence
Daddi-Moussa-Ider, Abdallah
2015-01-01T23:59:59.000Z
Understanding the dynamics of particles in turbulent flow is important in many environmental and industrial applications. In this paper, the statistics of particle pair orientation is numerically studied in homogeneous isotropic turbulent flow, with Taylor microscale Rynolds number of 300. It is shown that the Kolmogorov scaling fails to predict the observed probability density functions (PDFs) of the pair rotation rate and the higher order moments accurately. Therefore, a multifractal formalism is derived in order to include the intermittent behavior that is neglected in the Kolmogorov picture. The PDFs of finding the pairs at a given angular velocity for small relative separations, reveals extreme events with stretched tails and high kurtosis values. Additionally, The PDFs are found to be less intermittent and follow a complementary error function distribution for larger separations.
A pair of oscillators interacting with a common heat bath
G. W. Ford; R. F. O'Connell
2014-08-25T23:59:59.000Z
Here the problem considered is that of a pair of oscillators coupled to a common heat bath. Many, if not most, discussions of a single operator coupled to a bath have used the independent oscillator model of the bath. However, that model has no notion of separation, so the question of phenomena when the oscillators are near one another compared with when they are widely separated cannot be addressed. Here the Lamb model of an oscillator attached to a stretched string is generalized to illustrate some of these questions. The coupled Langevin equations for a pair of oscillators attached to the string at different points are derived and their limits for large and small separations obtained. Finally, as an illustration of a different phenomenon, the fluctuation force between a pair of masses attached to the string is calculated, with closed form expressions for the force at small and large separations.
Tailored photon-pair generation in optical fibers
Offir Cohen; Jeff S. Lundeen; Brian J. Smith; Graciana Puentes; Peter J. Mosley; Ian A. Walmsley
2009-04-14T23:59:59.000Z
We experimentally control the spectral structure of photon pairs created via spontaneous four-wave mixing in microstructured fibers. By fabricating fibers with designed dispersion, one can manipulate the photons' wavelengths, joint spectrum, and, thus, entanglement. As an example, we produce photon-pairs with no spectral correlations, allowing direct heralding of single photons in pure-state wave packets without filtering. We achieve an experimental purity of $85.9\\pm1.6%$, while theoretical analysis and preliminary tests suggest 94.5% purity is possible with a much longer fiber.
The Schwinger pair production rate in confining theories via holography
Daisuke Kawai; Yoshiki Sato; Kentaroh Yoshida
2014-06-02T23:59:59.000Z
We study the Schwinger pair production in confining theories. The production rate in an external electric field E is numerically evaluated by using the holographic description. There exist two kinds of critical values of the electric field, i) E=E_c, above which there is no potential barrier and particles are freely generated, ii) E=E_s, below which the confining string tension dominates the electric field and the pair production does not occur. We argue the universal exponents associated with the critical behaviors.
Magnetic moments of T=3/2 mirror pairs
Perez, S. M. [Department of Physics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa); iThemba LABS, P. O. Box 722, Somerset West 7129 (South Africa); Richter, W. A. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Brown, B. A. [Department of Physics and Astronomy, and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Horoi, M. [Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859 (United States)
2010-12-15T23:59:59.000Z
We predict values of the magnetic moments of T=3/2 proton-rich fp-shell nuclei in the mass range A=43-53, by using known values for their neutron-rich mirrors together with shell-model estimates for small quantities. We extend the analysis to those T=3/2 sd-shell mirror pairs for which both the T{sub z}=-3/2 and T{sub z}=+3/2 magnetic moments have been measured. We find that these obey the same linear relation as previously deduced for T=1/2 mirror pairs.
Pairing Gaps, Pseudogaps, and Phase Diagrams for Cuprate Superconductors
Yang Sun; Mike Guidry; Cheng-Li Wu
2007-02-21T23:59:59.000Z
We use a symmetry-constrained variational procedure to construct a generalization of BCS to include Cooper pairs with non-zero momentum and angular momentum. The resulting gap equations are solved at zero and finite temperature, and the doping-dependent solutions are used to construct gap and phase diagrams. We find a pseudogap terminating at a critical doping that may be interpreted in terms of both competing order and preformed pairs. The strong similarity between observation and predicted gap and phase structure suggests that this approach may provide a unified description of the complex structure observed for cuprate superconductors.
A pair spectrometer for measuring multipolarities of energetic nuclear transitions
J. Gulys; T. J. Ketel; A. J. Krasznahorkay; M. Csatls; L. Csige; Z. Gcsi; M. Hunyadi; A. Krasznahorkay; A. Vitz; T. G. Tornyi
2015-04-02T23:59:59.000Z
A multi-detector array has been designed and constructed for the simultaneous measurement of energy- and angular correlations of electron-positron pairs. Experimental results are obtained over a wide angular range for high-energy transitions in 16O, 12C and 8Be. A comparison with GEANT simulations demonstrates that angular correlations between 50 and 180 degrees of the electron-positron pairs in the energy range between 6 and 18 MeV can be determined with sufficient resolution and efficiency.
Flexible generation of correlated photon pairs in different frequency ranges
Fernando Oster; Christoph H Keitel; Mihai Macovei
2012-05-30T23:59:59.000Z
The feasibility to generate correlated photon pairs at variable frequencies is investigated. For this purpose, we consider the interaction of an off-resonant laser field with a two-level system possessing broken inversion symmetry. We show that the system generates non-classical photon pairs exhibiting strong intensity-intensity correlations. The intensity of the applied laser tunes the degree of correlation while the detuning controls the frequency of one of the photons which can be in the THz-domain. Furthermore, we observe the violation of a Cauchy-Schwarz inequality characterizing these photons.
Gomez-Ceballos, Guillelmo
We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant ...
Batool, Nazia; Saleem, H. [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)] [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)
2013-10-15T23:59:59.000Z
The linear and nonlinear dynamics of pair-ion (PI) and pair-ion-electron plasmas (PIE) have been investigated in a cylindrical geometry with a sheared plasma flow along the axial direction having radial dependence. The coupled linear dispersion relation of low frequency electrostatic waves has been presented taking into account the Guassian profile of density and linear gradient of sheared flow. It is pointed out that the quasi-neutral cold inhomogeneous pure pair ion plasma supports only the obliquely propagating convective cell mode. The linear dispersion relation of this mode has been solved using boundary conditions. The nonlinear structures in the form of vortices formed by different waves have been discussed in PI and PIE plasmas.
Blind subpixel Point Spread Function estimation from scaled image pairs
Paris-Sud XI, Universit de
Blind subpixel Point Spread Function estimation from scaled image pairs Mauricio Delbracio Andr, causing aliasing effects. This work introduces a blind algorithm for the subpixel estimation of the point shows that the proposed algorithm reaches the accuracy levels of the best non- blind state
A Comparison of h2 and MMM for Mutex Pair
Holte, Robert
are different from one another. The purpose of this paper is to study the effects on search performance when%-24%) whereas MMM's errors have very little effect on search speed or subop- timality, even when its sample size Edmonton, AB, Canada T6G 2E8, holte@cs.ualberta.ca Abstract. In state space search or planning, a pair
List of things to bring: Notes Socks (5 pairs)
Lougheed, Stephen
) Light weight fast drying pants are preferable. Shorts (one pair) Swim suit t-shirts (3-4) long-sleeved shirts (1-2) warm sweater or lightweight coat We may experience nightitme temperatures of down toclose or two Pencils are for your field books (prefered to ink which runs in humid weather). Important #12
Cherenkov radiation and pair production by particles traversing laser beams
I. M. Dremin
2002-03-01T23:59:59.000Z
It is shown that Cherenkov radiation can be observed at TESLA in electron collisions with optical laser pulses. The prospects for it to be observed at SLC, LEP, LHC and RHIC are discussed. The conclusions are compared with results for pair production.
Calculating coherent pair production with Monte Carlo methods
Bottcher, C.; Strayer, M.R.
1989-01-01T23:59:59.000Z
We discuss calculations of the coherent electromagnetic pair production in ultra-relativistic hadron collisions. This type of production, in lowest order, is obtained from three diagrams which contain two virtual photons. We discuss simple Monte Carlo methods for evaluating these classes of diagrams without recourse to involved algebraic reduction schemes. 19 refs., 11 figs.
Bose Einstein correlations of neutral pion pairs at LEP
M. Boutemeur; G. Giacomelli
2005-10-10T23:59:59.000Z
With the OPAL detector at LEP we measured at energies around the Z0 peak the Bose-Einstein Correlations (BECs) of neutral pion pairs. We compare the results of this measurement with former results obtained at LEP for hadrons including those obtained from Fermi-Dirac Correlations (FDCs).
Singlet Free Energies of a Static Quark-Antiquark Pair
Konstantin Petrov
2004-09-01T23:59:59.000Z
We study the singlet part of the free energy of a static quark anti-quark pair at finite temperature in three flavor QCD with degenerate quark masses using $N_{\\tau}=4$ and 6 lattices with Asqtad staggered fermion action. We look at thermodynamics of the system around phase transition and study its scaling with lattice spacing and quark masses.
Improved Approximations for Fermion Pair Production in Inhomogeneous Electric Fields
Sang Pyo Kim; Don N. Page
2007-01-31T23:59:59.000Z
Reformulating the instantons in a complex plane for tunneling or transmitting states, we calculate the pair-production rate of charged fermions in a spatially localized electric field, illustrated by the Sauter electric field E_0 sech^2 (z/L), and in a temporally localized electric field such as E_0 sech^2 (t/T). The integration of the quadratic part of WKB instanton actions over the frequency and transverse momentum leads to the pair-production rate obtained by the worldline instanton method, including the prefactor, of Phys. Rev. D72, 105004 (2005) and D73, 065028 (2006). It is further shown that the WKB instanton action plus the next-to-leading order contribution in spinor QED equals the WKB instanton action in scalar QED, thus justifying why the WKB instanton in scalar QED can work for the pair production of fermions. Finally we obtain the pair-production rate in a spatially localized electric field together with a constant magnetic field in the same direction.
Observation of the Nernst signal generated by fluctuating Cooper pairs
Loss, Daniel
. The Nernst effect, the generation of a transverse electric field by a longitudinal thermal gradient, has with the quanta of electric1 (e2 /h) or thermal11 (2 k2 BT/3h) conductance. However, in the notation used by USHLETTERS Observation of the Nernst signal generated by fluctuating Cooper pairs A. POURRET1 , H
Abstract polymer models with general pair interactions Aldo Procacci
Procacci, Aldo
Abstract polymer models with general pair interactions Aldo Procacci Dep. Matem´atica-ICEx, UFMG (i.e. not necessarily hard core or repulsive). A concrete example is given in which polymers are r0 (possibly attractive), of the type 1/rd+ with > 0. 1. Introduction The abstract polymer gas is an important
Transition maps between the 24 bases for a Leonard pair
Nomura, Kazumasa
2007-01-01T23:59:59.000Z
Let $V$ denote a vector space with finite positive dimension. We consider a pair of linear transformations $A : V \\to V$ and $A^* : V \\to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is irreducible tridiagonal and the matrix representing $A^*$ is diagonal. (ii) There exists a basis for $V$ with respect to which the matrix representing $A^*$ is irreducible tridiagonal and the matrix representing $A$ is diagonal. We call such a pair a Leonard pair on $V$. In an earlier paper we described 24 special bases for $V$. One feature of these bases is that with respect to each of them the matrices that represent $A$ and $A^*$ are (i) diagonal and irreducible tridiagonal or (ii) irreducible tridiagonal and diagonal or (iii) lower bidiagonal and upper bidiagonal or (iv) upper bidiagonal and lower bidiagonal. For each ordered pair of bases among the 24, there exists a unique linear transformation from $V$ to $V$ that sends the first basis to the seco...
Creation and pinning of vortex-antivortex pairs
Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.
2006-01-01T23:59:59.000Z
Computer modeling is reported about the creation and pinning of a magnetic vortex-antivortex (V-AV) pair in a superconducting thin film, due to the magnetic field of a vertical magnetic dipole above the film, and two antidot pins inside the film...
Pair Production of Tau Sneutrinos at Linear Colliders
V. Ari; O. Cakir
2010-07-15T23:59:59.000Z
The pair production of tau sneutrinos in $e^{+}e^{-}$ collisions and their subsequent decays are studied in a framework of the supersymmetric extension of the standard model. We present an analysis for the parameter space (BR vs. mass) which could be explored at the future high energy $e^{+}e^{-}$ colliders.
Matched Pairs Procedures Two Sample Procedures General Guidelines t Procedures
Watkins, Joseph C.
this, researchers randomly chose a collection of bags of wheat soy blend bound for Haiti, marked them blend. Factory Haiti Factory Haiti Factory Haiti Factory Haiti 44 40 45 38 39 43 50 37 50 37 32 40 52 38, respectively, at the factory and in Haiti. > t.test(factory, haiti, alternative = c("greater"),mu = 0, paired
Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT
Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT Scans: Correlations with Lung Function and Mean Lung Density Tsuneo Yamashiro, MD, Shin Matsuoka, MD, PhD, Brian J. Bartholmai, MD, Rau: To evaluate the relationship between measurements of lung volume (LV) on inspiratory/expiratory computed
RELAXATION OF BLAZAR-INDUCED PAIR BEAMS IN COSMIC VOIDS
Miniati, Francesco [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Elyiv, Andrii, E-mail: fm@phys.ethz.ch [Institut d'Astrophysique et de Geophysique, Universite de Liege, B-4000 Liege (Belgium)
2013-06-10T23:59:59.000Z
The stability properties of a low-density ultrarelativistic pair beam produced in the intergalactic medium (IGM) by multi-TeV gamma-ray photons from blazars are analyzed. The problem is relevant for probes of magnetic field in cosmic voids through gamma-ray observations. In addition, dissipation of such beams could considerably affect the thermal history of the IGM and structure formation. We use a Monte Carlo method to quantify the properties of the blazar-induced electromagnetic shower, in particular the bulk Lorentz factor and the angular spread of the pair beam generated by the shower, as a function of distance from the blazar itself. We then use linear and nonlinear kinetic theory to study the stability of the pair beam against the growth of electrostatic plasma waves, employing the Monte Carlo results for our quantitative estimates. We find that the fastest growing mode, like any perturbation mode with even a very modest component perpendicular to the beam direction, cannot be described in the reactive regime. Due to the effect of nonlinear Landau damping, which suppresses the growth of plasma oscillations, the beam relaxation timescale is found to be significantly longer than the inverse Compton loss time. Finally, density inhomogeneities associated with cosmic structure induce loss of resonance between the beam particles and plasma oscillations, strongly inhibiting their growth. We conclude that relativistic pair beams produced by blazars in the IGM are stable on timescales that are long compared with the electromagnetic cascades. There appears to be little or no effect of pair beams on the IGM.
Transversity Signal in two Hadron Pair Production in COMPASS
H. Wollny; for the COMPASS collaboration
2009-07-06T23:59:59.000Z
Measuring single spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarized target gives a handle to investigate the transversity distribution and transverse momentum dependent distribution functions. In the years 2002, 2003 and 2004 COMPASS took data with a transversely polarized deuteron target and in the year 2007 with a proton target. Three channels for accessing transversity have been analysed. Azimuthal asymmetries in the production of hadron pairs, involving the polarized two hadron interference fragmentation function, azimuthal asymmetries in the production of single hadrons, involving the Collins fragmentation function and polarization measurements of spin-${1/2} \\hbar$ particles like $\\Lambda$-Hyperons via their self analyzing weak decay. In the following we will focus on new preliminary results from the analysis of two hadron pair asymmetries measured with the proton target.
Threshold energy surface and Frenkel-pair resistivity for Cu
King, W.E.; Merkle, K.L.; Meshii, M.
1982-01-01T23:59:59.000Z
In-situ electrical resistivity damage-rate measurements in the high voltage electron microscope have been used to study electron-irradiation-induced defect production in copper single crystals at T < 10/sup 0/K. Analysis of the directional and energy dependence yields a threshold energy surface that is significantly different from those of previous investigations: two pockets of low threshold energy centered at <100> and <110> surrounded by regions of much higher threshold energy. The corresponding damage function exhibits a plateau of 0.6 Frenkel pairs. the present results imply a Frenkel pair resistivity for C of (2.75/sub -0.2//sup +0.6/) x ..cap omega..-cm.
Eigenstate Localization in an Asymmetric Coupled Quantum Well Pair
Mialitsin, A.; Schmult, S.; Solov'yov, I. A.; Fluegel, B.; Mascarenhas, A.
2012-06-01T23:59:59.000Z
Optical pumping of a type-I/type-II coupled asymmetric quantum well pair induces a spatially separated two dimensional charge carriers plasma in the well's wide and narrow parts. Treating the two coupled wells as a single system we find that the eigenstate probability distribution localizes exclusively either in the wide or the narrow parts of the well pair. The energy of the narrow-well localized state determines the minimal excitation energy for optically pumped charge carriers separation. In a previously used design [Guliamov et al., PRB 64 035314 (2001)] this narrow well transition energy was measured to correspond to a wavelength of 646 nm. We propose modifications to the design suggested earlier with the purpose of pushing up the energy required for the optical pumping of the two-dimensional plasma into the green and blue regions of the visible spectrum.
Electron and positron pair production of compact stars
Wen-Biao Han; Remo Ruffini; She-Sheng Xue
2012-09-15T23:59:59.000Z
Neutral stellar core at or over nuclear densities is described by a positive charged baryon core and negative charged electron fluid since they possess different masses and interactions. Based on a simplified model of a gravitationally collapsing or pulsating baryon core, we approximately integrate the Einstein-Maxwell equations and the equations for the number and energy-momentum conservation of complete degenerate electron fluid. We show possible electric processes that lead to the production of electron-positron pairs in the boundary of a baryon core and calculate the number and energy of electron-positron pairs. This can be relevant for understanding the energetic sources of supernovae and gamma-ray bursts.
Pair Instability Supernovae of Very Massive Population III Stars
Chen, Ke-Jung; Woosley, Stan; Almgren, Ann; Whalen, Daniel
2014-01-01T23:59:59.000Z
Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 Msun die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core collapse, to capture any dynamical instabilities that may be seeded by collapse and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning ari...
Pair Creation and an X-ray Free Electron Laser
R. Alkofer; M. B. Hecht; C. D. Roberts; S. M. Schmidt; D. V. Vinnik
2001-08-17T23:59:59.000Z
Using a quantum kinetic equation coupled to Maxwell's equation we study the possibility that focused beams at proposed X-ray free electron laser facilities can generate electric field strengths large enough to cause spontaneous electron-positron pair production from the QED vacuum. Our approach yields the time and momentum dependence of the single particle distribution function. Under conditions reckoned achievable at planned facilities, repeated cycles of particle creation and annihilation take place in tune with the laser frequency. However, the peak particle number density is insensitive to this frequency and one can anticipate the production of a few hundred particle pairs per laser period. Field-current feedback and quantum statistical effects are small and can be neglected in this application of non-equilibrium quantum mean field theory.
Observation of ?c1 Decays into Vector Meson Pairs ??, ?? and, ??
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ablikim, M.; Achasov, M. N.; An, L.; An, Q.; An, Z. H.; Bai, J. Z.; Baldini, R.; Ban, Y.; Becker, J.; Berger, N.; Bertani, M.; Bian, J. M.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cao, G. F.; Cao, X. X.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denysenko, I.; Destefanis, M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Duan, M. Y.; Fan, R. R.; Fang, J.; Fang, S. S.; Feng, C. Q.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Greco, M.; Grishin, S.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, B.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jia, L. K.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kavatsyuk, M.; Komamiya, S.; Kuehn, W.; Lange, J. S.; Leung, J. K. C.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, Lei; Li, N. B.; Li, Q. J.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, G. C.; Liu, H.; Liu, H. B.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K.; Liu, K. Y.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Y. W.; Liu, Yong; Liu, Z. A.; Liu, Z. Q.; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, T.; Ma, X.; Ma, X. Y.; Maggiora, M.; Malik, Q. A.; Mao, H.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Muchnoi, N. Yu.; Nefedov, Y.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pelizaeus, M.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Pun, C. S. J.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, X. Y.; Sonoda, S.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. D.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tang, X. F.; Tian, H. L.; Toth, D.; Varner, G. S.; Wan, X.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Wen, Q. G.; Wen, S. P.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, W.; Wu, Z.; Xiao, Z. J.; Xie, Y. G.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Y.; Xu, Z. R.; Xu, Z. Z.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, M.; Yang, T.; Yang, Y.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, L.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, L.; Zhang, S. H.; Zhang, T. R.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, Jiawei; Zhao, Jingwei; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhao, Z. L.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zheng, Z. P.; Zhong, B.; Zhong, J.; Zhong, L.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Zuo, J. X.; Zweber, P.
2011-08-01T23:59:59.000Z
Using (1064)10? ?(3686) events accumulated with the BESIII detector at the BEPCII e?e? collider, we present the first measurement of decays of ?c1 to vector meson pairs ??, ??, and ??. The branching fractions are measured to be (4.40.30.5)10??, (6.00.30.7)10??, and (2.20.60.2)10??, for ?c1 ???, ??, and ??, respectively, which indicates that the hadron helicity selection rule is significantly violated in ?cJ decays. In addition, the measurement of ?cJ??? provides the first indication of the rate of doubly OZI-suppressed ?cJ decay. Finally, we present improved measurements for the branching fractions of ?c0 and ?c2 to vector meson pairs.
Flow localization in sheet specimens with pairs of holes
Geltmacher, A.B. [FM Technologies, Fairfax, VA (United States); Koss, D.A. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Metals Science and Engineering; Stout, M.G. [Los Alamos National Lab., NM (United States); Matic, P. [Naval Research Lab., Washington, DC (United States). Mechanics of Materials Dept.
1998-03-01T23:59:59.000Z
The deformation localization behavior of sheet specimens containing geometric perturbations in the form of pairs of through-thickness holes is examined. Both experiments and computational modeling are performed in either uniaxial or equal-biaxial tension in order to examine the effect of applied loading path on the far-field strain needed to initiate localized necking in the ligament between the hole pairs. The models also examine the influence of hole spacing and matrix strain hardening on ligament localization. The far-field strain needed to cause the localization of the ligament is shown to increase as the biaxiality of the loading path increases, the hole spacing increases, and the strain-hardening exponent increases. The present study also indicates that the onset of localized necking can be predicted by employing the Hill criterion, if the local strain states within the ligament are taken into account.
Proton-neutron pairing energies in N=Z nuclei at finite temperature
K. Kaneko; M. Hasegawa
2005-08-27T23:59:59.000Z
Thermal behavior of isoscalar and isovector proton-neutron (pn) pairing energies at finite temperature are investigated by the shell model calculations. These pn pairing energies can be estimated by double differences of "thermal" energies which are extended from the double differences of binding energies as the indicators of pn pairing energies at zero temperature. We found that the delicate balance between isoscalar and isovector pn pairing energies at zero temperature disappears at finite temperature. When temperature rises, while the isovector pn pairing energy decreases, the isoscalar pn pairing energy rather increases. We discuss also the symmetry energy at finite temperature.
Fourier Transform Pairs The Fourier transform transforms a function of
Masci, Frank
Fourier Transform Pairs The Fourier transform transforms a function of time, f(t), into a function of frequency, F(s): F {f(t)}(s) = F(s) = Z - f(t)e- j2st dt. The inverse Fourier transform transforms a func. The inverse Fourier transform of the Fourier trans- form is the identity transform: f(t) = Z - Z - f()e- j2s
Interference of Cooper Pairs Emitted from Independent Superconductors
Mauro Iazzi; Kazuya Yuasa
2010-05-16T23:59:59.000Z
We discuss the interference in the two-particle distribution of the electrons emitted from two independent superconductors. It is clarified that, while the interference appearing in the antibunching correlation is due to the Hanbury Brown and Twiss effect, that in the positive correlation due to superconductivity is intrinsically different and is nothing but the first-order interference of Cooper pairs emitted from different sources. This is the equivalent of the interference of two independent Bose-Einstein condensates.
Top quark pair production cross section at the Tevatron
Cortiana, Giorgio; /INFN, Padua /Padua U.
2008-04-01T23:59:59.000Z
Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.
HBT interferometry with quantum transport of the interfering pair
Yu, Li-Li; Wong, Cheuk-Yin
2008-01-01T23:59:59.000Z
In the late stage of the evolution of a pion system in high-energy heavy-ion collisions when pions undergo multiple scatterings, the quantum transport of the interfering pair of identical pions plays an important role in determining the characteristics of the Hanbury-Brown-Twiss (HBT) interference. We study the quantum transport of the interfering pair using the path-integral method, in which the evolution of the bulk matter is described by relativistic hydrodynamics while the paths of the two interfering pions by test particles following the fluid positions and velocity fields. We investigate in addition the effects of secondary pion sources from particle decays, for nuclear collisions at AGS and RHIC energies. We find that quantum transport of the interfering pair leads to HBT radii close to those for the chemical freeze-out configuration. Particle decays however lead to HBT radii greater than those for the chemical freeze-out configuration. As a consequence, the combined effects give rise to HBT radii betw...
Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110). Abstract: Understanding hydrogen formation on TiO2...
Single-molecule derivation of salt dependent base-pair free energies in DNA
Ritort, Felix
Single-molecule derivation of salt dependent base-pair free energies in DNA Josep M. Hugueta measurements of base-pair free energies in DNA are obtained in thermal denaturation experiments, which depend on several as- sumptions. Here we report measurements of the DNA base-pair free energies based
Gluon polarisation from high transverse momentum hadron pairs production (COMPASS)
L. Silva; for the COMPASS Collaboration
2010-10-08T23:59:59.000Z
A new preliminary result of a gluon polarisation \\Delta G/G obtained selecting high transverse momentum hadron pairs in DIS events with Q^2>1 (GeV/c)^2 is presented. Data has been collected by COMPASS at CERN during the 2002-2004 years. In the extraction of $\\Delta G/G$ contributions coming from the leading order $\\gamma q$ and QCD processes are taken into account. A new weighting method based on a neural network approach is used. Also a preliminary result of \\Delta G/G for events with Q^2<1 (GeV/c)^2 is presented.
Free energy and criticality in the nucleon pair breaking process
M. Guttormsen; R. Chankova; M. Hjorth-Jensen; J. Rekstad; S. Siem; A. Schiller; D. J. Dean
2003-07-29T23:59:59.000Z
Experimental level densities for 171,172Yb, 166,167Er, 161,162Dy, and 148,149Sm are analyzed within the microcanonical ensemble. In the even isotopes at excitation energies E energy F signals the transition from zero to two quasiparticles. For E > 2 MeV, the odd and even isotopes reveal a surprisingly constant F at a critical temperature Tc of appr. 0.5 MeV, indicating the continuous melting of nucleon Cooper pairs as function of excitation energy.
HOM Survey of the First CEBAF Upgrade Style Cavity Pair
Marhauser, Frank; Davis, G; Drury, Michael; Grenoble, Christiana; Hogan, John; Manus, Robert; Preble, Joseph; Reece, Charles; Rimmer, Robert; Tian, Kai
2009-05-01T23:59:59.000Z
The planned upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Laboratory (JLab) requires ten new superconducting rf (SRF) cavity cryomodules to double the beam energy to the envisaged 12 GeV. Adequate cavity Higher Order Mode (HOM) suppression is essential to avoid multipass, multibunch beam break-up (BBU) instabilities of the recirculating beam. We report on detailed HOM surveys performed for the first two upgrade style cavities tested in a dedicated cavity pair cryomodule at 2K. The safety margin to the BBU threshold budget at 12 GeV has been assessed.
Infinitely many pairs of primes $p$ and $p+2$
Guangchang Dong
2015-03-20T23:59:59.000Z
When $p$ and $p+2$ are primes, such as $3,5; 5,7; 11,13; 17,19; ...$. We call them pairs of prime twins. In this paper we use sieve method (Liu sieve) to construct the weak solution (i.e. formal solution) of prime twins. Then we use auxiliary special 4 sieve problem and its biological model to prove that weak equals classical, i.e. the weak solution is a classical one, hence the numbers of prime twins are infinite.
Radiative emission of neutrino pair free of quantum electrodynamic backgrounds
M. Yoshimura; N. Sasao; M. Tanaka
2015-01-23T23:59:59.000Z
A scheme of quantum electrodynamic (QED) background-free radiative emission of neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between wave vector along propagating direction in wave guide (and in a photonic-crystal type fiber) and frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos.
A semiconductor source of triggered entangled photon pairs?
A. Gilchrist; K. J. Resch; A. G. White
2006-08-08T23:59:59.000Z
The realisation of a triggered entangled photon source will be of great importance in quantum information, including for quantum key distribution and quantum computation. We show here that: 1) the source reported in ``A semiconductor source of triggered entangled photon pairs''[1. Stevenson et al., Nature 439, 179 (2006)]} is not entangled; 2) the entanglement indicators used in Ref. 1 are inappropriate, relying on assumptions invalidated by their own data; and 3) even after simulating subtraction of the significant quantity of background noise, their source has insignificant entanglement.
Metal Absorption Systems in Spectra of Pairs of QSOs
David Tytler; Mark Gleed; Carl Melis; Angela Chapman; David Kirkman; Dan Lubin; Pascal Paschos; Tridivesh Jena; Arlin P. S. Crotts
2007-11-17T23:59:59.000Z
We present the first large sample of absorption systems in paired QSOs consisting of 691 absorption systems in the spectra of 310 QSOs including 170 pairings. All these absorption systems have metal lines, usually C IV or Mg II. We see 17 cases of absorption in one line-of-sight within 200 km/s (1 Mpc) of absorption in the paired line-of-sight with the probability at least approx 50% at 100kpc, declining rapidly to 23% at 100 - 200 kpc. We detect clustering on 0.5Mpc scales and see a hint of the "fingers of God" redshift-space distortion. The distribution matches absorbers arising in galaxies at z=2 with a normal correlation function and systematic infall velocities but unusually low random pair-wise velocity differences. Absorption in gas flowing out from galaxies at a mean velocity of 250 km/s would produce vastly more elongation than we see. The UV absorption from fast winds that Adelberger et al. 2005 see in spectra of LBGs is not representative of the absorption that we see. Either the winds are confined to LBGs, or they can not extend to 40 kpc with large velocities, while continuing to make UV absorption we see, implying most metals were in place in the IGM long before z=2. Separately, when we examine the absorption seen when a sight line passes a second QSO, we see 19 absorbers within 400 km/s of the partner QSO. The probability of seeing absorption is approximately constant for impact parameters 0.1 - 1.5 Mpc. Perhaps we do not see a rapid rise in the probability at small impact parameters because the UV from QSOs destroys some absorbers near to the QSOs. The 3D distribution of 64 absorbers around 313 QSOs is to first order isotropic, with just a hint of the anisotropy expected if the QSO UV emission is beamed, or alternatively QSOs might emit UV isotropically but for a surprisingly short time of only 0.3Myr.
Seems a Fate in It: Misdirection and Foreshadowing in Bleak House and A Pair of Blue Eyes
Bradfield, Meredith
2013-01-01T23:59:59.000Z
for Action in A Pair of Blue Eyes. English Literature in2013). Hardy, Thomas. A Pair of Blue Eyes. Harmondsworth,aware of Thomas Hardy. A Pair of Blue Eyes. (Harmondsworth,
Electrostatic ion waves in non-Maxwellian pair-ion plasmas
Arshad, Kashif [Department of Physics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shadhra Valley Road, Islamabad 44000 (Pakistan); Mahmood, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shadhra Valley Road, Islamabad 44000 (Pakistan)
2010-12-15T23:59:59.000Z
The electrostatic ion waves are studied for non-Maxwellian or Lorentzian distributed unmagnetized pair-ion plasmas. The Vlasov equation is solved and damping rates are calculated for electrostatic waves in Lorentzian pair-ion plasmas. The damping rates of the electrostatic ion waves are studied for the equal and different ion temperatures of pair-ion species. It is found that the Landau damping rate of the ion plasma wave is increased in Lorentzian plasmas in comparison with Maxwellian pair-ion plasmas. The numerical results are also presented for illustration by taking into account the parameters reported in fullerene pair-ion plasma experiments.
Search for pair production of second generation scalar leptoquarks
Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Northeastern U.
2008-08-01T23:59:59.000Z
We report on a search for the pair production of second generation scalar leptoquarks (LQ) in p{bar p} collisions at the center of mass energy {radical}s = 1.96TeV using a data set corresponding to an integrated luminosity of 1.0 fb{sup -1} collected with the D0 experiment at the Fermilab Tevatron Collider. Topologies arising from the LQ{ovr LQ} {yields} {mu}q{nu}q and LQ{ovr LQ} {yields} {mu}q{mu}q decay modes are investigated. No excess of data over the standard model prediction is observed and upper limits on the leptoquark pair production cross section are derived at the 95% C.L. as a function of the leptoquark mass and the branching fraction {beta} for the decay LQ {yields} {mu}q. These are interpreted as lower limits on the leptoquark mass as a function of {beta}. For {beta} = 1 (0.5), scalar second generation leptoquarks with masses up to 316GeV (270GeV) are excluded.
Creation of Electron Spinless Pairs in the Superconductivity
V. N. Minasyan
2009-03-28T23:59:59.000Z
First, it is demonstrated that the Froolich Hamiltonian of system in the superconductivity, proposed by the model of a phonon gas and an electron gas mixture, contains a subtle error. In this respect, we present a correct form of the Froolich Hamiltonian of system where the term of the interaction between the phonon modes and the density modes of the electron modes is described by the term of scattering, introduced by the Froolich in a phonon gas electron gas mixture. The later is removed by a canonical transformation of the Froolich Hamiltonian by an appearance of the attractive interaction mediated via the electron modes, which leads to a bound state on a spinless electron pairs. In this letter, we show that the Cooper approximation as the constancy of the density states within around of the Fermi level has a flaw because the effective attractive forces cannot create the Cooper pairs into energetic gap at the Fermi level. In this letter, we find a condition for density metal which determines metal as superconductor.
Nonzero angular momentum pairing correlation in shell model
S. Haq; Y. Sadeq; I. M. Hamammu
2008-10-07T23:59:59.000Z
A simple approximation to shell model is proposed in which the low energy excitation spectra corresponds to the identical nucleons occupying the same single particle states where they preferred to form pairs for the ground states. We call this approximation as nonzero angular momentum pairing shell model. It not only reduces the dimensionality of the shell model but also matches the number of low energy levels in experimental spectra for few cases where exact shell model predicts many more states. The special focus has been done to consider the realistic interaction derived from free nucleon-nucleon scattering data to cope with the experimental spectra. The proposed approximation to shell model has been applied to calculate the energy spectra of O18 and Ni58 nuclei where only two neutrons occupy the valence states outside the core. When compared with the experimental data, the results are found to be encouraging. It is expected that results will be more pronounced if the even-even nuclei with higher number of valence nucleons are considered.
Modeling the secular evolution of migrating planet pairs
Michtchenko, Tatiana A
2011-01-01T23:59:59.000Z
The subject of this paper is the secular behaviour of a pair of planets evolving under dissipative forces. In particular, we investigate the case when dissipative forces affect the planetary semi-major axes and the planets move inward/outward the central star, in a process known as planet migration. To perform this investigation, we introduce fundamental concepts of conservative and dissipative dynamics of the three-body problem. Based on these concepts, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one...
Top quark pair production and top quark properties at CDF
Chang-Seong Moon
2014-11-01T23:59:59.000Z
We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.
FINDING THE FIRST COSMIC EXPLOSIONS. I. PAIR-INSTABILITY SUPERNOVAE
Whalen, Daniel J.; Smidt, Joseph; Lovekin, C. C. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Frey, Lucille H. [HPC-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johnson, Jarrett L.; Hungerford, Aimee L. [XTD-6, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Holz, Daniel E. [Enrico Fermi Institute, Department of Physics, and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Woosley, S. E. [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States)
2013-11-10T23:59:59.000Z
The first stars are the key to the formation of primitive galaxies, early cosmological reionization and chemical enrichment, and the origin of supermassive black holes. Unfortunately, in spite of their extreme luminosities, individual Population III (Pop III) stars will likely remain beyond the reach of direct observation for decades to come. However, their properties could be revealed by their supernova explosions, which may soon be detected by a new generation of near-IR (NIR) observatories such as JWST and WFIRST. We present light curves and spectra for Pop III pair-instability supernovae calculated with the Los Alamos radiation hydrodynamics code RAGE. Our numerical simulations account for the interaction of the blast with realistic circumstellar envelopes, the opacity of the envelope, and Lyman absorption by the neutral intergalactic medium at high redshift, all of which are crucial to computing the NIR signatures of the first cosmic explosions. We find that JWST will detect pair-instability supernovae out to z ?> 30, WFIRST will detect them in all-sky surveys out to z ? 15-20, and LSST and Pan-STARRS will find them at z ?< 7-8. The discovery of these ancient explosions will probe the first stellar populations and reveal the existence of primitive galaxies that might not otherwise have been detected.
State recovery and lockstep execution restart in a system with multiprocessor pairing
Gara, Alan; Gschwind, Michael K; Salapura, Valentina
2014-01-21T23:59:59.000Z
System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus. Each selectively paired processor core is includes a transactional execution facility, whereing the system is configured to enable processor rollback to a previous state and reinitialize lockstep execution in order to recover from an incorrect execution when an incorrect execution has been detected by the selective pairing facility.
Valley pair qubits in double quantum dots of gapped graphene
G. Y. Wu; N. -Y. Lue; L. Chang
2011-07-03T23:59:59.000Z
The rise of graphene opens a new door to qubit implementation, as discussed in the recent proposal of valley pair qubits in double quantum dots of gapped graphene (Wu et al., arXiv: 1104.0443 [cond-mat.mes-hall]). The work here presents the comprehensive theory underlying the proposal. It discusses the interaction of electrons with external magnetic and electric fields in such structures. Specifically, it examines a strong, unique mechanism, i.e., the analogue of the 1st-order relativistic effect in gapped graphene. This mechanism is state mixing free and allows, together with the electrically tunable exchange coupling, a fast, all-electric manipulation of qubits via electric gates, in the time scale of ns. The work also looks into the issue of fault tolerance in a typical case, yielding at 10oK a long qubit coherence time (~O(ms)).
Dynamically tunable Fano resonance in periodically asymmetric graphene nanodisk pair
Zhang, Zhengren; Fan, Yuancheng; Yin, Pengfei; Zhang, Liwei; Shi, Xi
2015-01-01T23:59:59.000Z
We present a dynamically frequency tunable Fano resonance planar device composed of periodically asymmetric graphene nanodisk pair for the mid-infrared region. There are two kinds of modes in this structure, that is, the symmetric mode and the antisymmetric mode. The resonance coupling between the symmetric and antisymmetric modes creates a classical Fano resonance. Both of the Fano resonance amplitude and frequency of the structure can be dynamically controlled by varying the Fermi energy of graphene. Resonance transition in the structure is studied to reveal the physical mechanism behind the dynamically tunable Fano resonance. The features of the Fano resonant graphene nanostructures should have promising applications in tunable THz filters, switches, and modulators.
EPR pairing dynamics in Hubbard model with resonant $U$
X. Z. Zhang; Z. Song
2015-04-28T23:59:59.000Z
We study the dynamics of the collision between two fermions in Hubbard model with on-site interaction strength $U$. The exact solution shows that the scattering matrix for two-wavepacket collision is separable into two independent parts, operating on spatial and spin degrees of freedom, respectively. The S-matrix for spin configuration is equivalent to that of Heisenberg-type pulsed interaction with the strength depending on $U$ and relative group velocity $\\upsilon _{r}$. This can be applied to create distant EPR pair, through a collision process for two fermions with opposite spins in the case of $\\left\\vert \\upsilon _{r}/U\\right\\vert =1$,\\ without the need for temporal control and measurement process. Multiple collision process for many particles is also discussed.
Reduction in maximum time uncertainty of paired time signals
Theodosiou, George E. (West Chicago, IL); Dawson, John W. (Clarendon Hills, IL)
1983-01-01T23:59:59.000Z
Reduction in the maximum time uncertainty (t.sub.max -t.sub.min) of a series of paired time signals t.sub.1 and t.sub.2 varying between two input terminals and representative of a series of single events where t.sub.1 .ltoreq.t.sub.2 and t.sub.1 +t.sub.2 equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t.sub.min) of the first signal t.sub.1 closer to t.sub.max and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20-800.
Reduction in maximum time uncertainty of paired time signals
Theodosiou, G.E.; Dawson, J.W.
1983-10-04T23:59:59.000Z
Reduction in the maximum time uncertainty (t[sub max]--t[sub min]) of a series of paired time signals t[sub 1] and t[sub 2] varying between two input terminals and representative of a series of single events where t[sub 1][<=]t[sub 2] and t[sub 1]+t[sub 2] equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t[sub min]) of the first signal t[sub 1] closer to t[sub max] and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20--800. 6 figs.
Reduction in maximum time uncertainty of paired time signals
Theodosiou, G.E.; Dawson, J.W.
1981-02-11T23:59:59.000Z
Reduction in the maximum time uncertainty (t/sub max/ - t/sub min/) of a series of paired time signals t/sub 1/ and t/sub 2/ varying between two input terminals and representative of a series of single events where t/sub 1/ less than or equal to t/sub 2/ and t/sub 1/ + t/sub 2/ equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t/sub min/) of the first signal t/sub 1/ closer to t/sub max/ and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20 to 800.
Reexamination of an anomaly in near-threshold pair production
De Braeckeleer, L.; Adelberger, E.G.; Garcia, A. (Physics Department FM-15, University of Washington, Seattle, Washington 98195 (United States))
1992-11-01T23:59:59.000Z
We investigated a reported anomaly in near-threshold pair production, using radioactive sources to measure the {gamma}+Ge{r arrow}{ital e}{sup +}+{ital e}{sup {minus}}+Ge cross-section at {ital E}{sub {gamma}}=1063, 1086, 1112, 1173, 1213, 1299, 1332, and 1408 keV. Although the data agree with the theory (numerical calculations based on an exact partial-wave formulation for a screened central potential) at the higher energies, the data lie above the theory at 1063, 1082, and 1112 keV. The discrepancy is reduced by including the final-state Coulomb interaction between the {ital e}{sup +} and {ital e}{sup {minus}}.
The Holmberg effect of Main galaxy pairs of the SDSS Data Release 4 (SDSS4)
Deng Xin-Fa; Ma Xin-Sheng; He Con-Gen; Luo Cheng-Hong; He Ji-Zhou
2006-05-12T23:59:59.000Z
We have investigated the Holmberg effect of Main galaxy pairs of the SDSS Data Release 4 (SDSS4). It is found that except i-z color the color indices between the two components of Main galaxy pairs clearly have significantly larger correlation coefficients. Further analyses also show that the Holmberg Effect of galaxies not only depends on the color indices but also on the morphological type for two components of pairs.
Dynamics of iron-acceptor-pair formation in co-doped silicon
Bartel, T.; Gibaja, F.; Graf, O.; Gross, D.; Kaes, M.; Heuer, M.; Kirscht, F. [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany)] [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany); Mller, C. [CiS Forschungsinstitut fr Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany) [CiS Forschungsinstitut fr Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany); TU Ilmenau, Institut fr Physik, Weimarer Str. 32, 98693 Ilmenau (Germany); Lauer, K. [CiS Forschungsinstitut fr Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)] [CiS Forschungsinstitut fr Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)
2013-11-11T23:59:59.000Z
The pairing dynamics of interstitial iron and dopants in silicon co-doped with phosphorous and several acceptor types are presented. The classical picture of iron-acceptor pairing dynamics is expanded to include the thermalization of iron between different dopants. The thermalization is quantitatively described using Boltzmann statistics and different iron-acceptor binding energies. The proper understanding of the pairing dynamics of iron in co-doped silicon will provide additional information on the electronic properties of iron-acceptor pairs and may become an analytical method to quantify and differentiate acceptors in co-doped silicon.
Cherenkov Radiation from e+e- Pairs and Its Effect on nu e Induced Showers
Mandal, Sourav K.; Klein, Spencer R.; Jackson, J. David
2005-01-01T23:59:59.000Z
5] J. V. Jelley, Cherenkov Radiation and its applications (calculated the Cherenkov radiation from e + e ? pairs as a? 2 [1?? 2 ?(?)]), the radiation is suppressed compared to
Momentum signatures for Schwinger pair production in short laser pulses with a sub-cycle structure
Florian Hebenstreit; Reinhard Alkofer; Gerald V. Dunne; Holger Gies
2009-04-20T23:59:59.000Z
We investigate electron-positron pair production from vacuum for short laser pulses with sub-cycle structure, in the nonperturbative regime (Schwinger pair production). We use the non-equilibrium quantum kinetic approach, and show that the momentum spectrum of the created electron-positron pairs is extremely sensitive to the sub-cycle dynamics -- depending on the laser frequency $\\omega$, the pulse length $\\tau$, and the carrier phase $\\phi$ -- and shows several distinctive new signatures. This observation could help not only in the design of laser pulses to optimize the experimental signature of Schwinger pair production, but also ultimately lead to new probes of light pulses at extremely short time scales.
Paho Lurie-Gregg; Jeff B. Schulte; David Roundy
2014-09-24T23:59:59.000Z
We introduce an approximation for the pair distribution function of the inhomogeneous hard sphere fluid. Our approximation makes use of our recently published averaged pair distribution function at contact which has been shown to accurately reproduce the averaged pair distribution function at contact for inhomogeneous density distributions. This approach achieves greater computational efficiency than previous approaches by enabling the use of exclusively fixed-kernel convolutions and thus allowing an implementation using fast Fourier transforms. We compare results for our pair distribution approximation with two previously published works and Monte-Carlo simulation, showing favorable results.
What Signals Do Packet-Pair Dispersions Carry? Xiliang Liu, Kaliappa Ravindran, and Dmitri Loguinov
Loguinov, Dmitri
of packet-pair probing in the context of a single-hop path and non-fluid cross-traffic. We identify three
What Signals Do Packet-pair Dispersions Carry? Xiliang Liu, Kaliappa Ravindran, and Dmitri Loguinov
Liu, Xiliang
of packet-pair probing in the context of a single-hop path and non-fluid cross-traffic. We identify three
Final state interactions at the threshold of Higgs boson pair production
Zhang, Zhentao
2015-01-01T23:59:59.000Z
We study the effect of final state interactions at the threshold of Higgs boson pair production in the Glashow-Weinberg-Salam model. We consider three major processes of the pair production in the model: lepton pair annihilation, ZZ fusion, and WW fusion. We find that the corrections caused by the effect for these processes are markedly different. According to our results, the effect can cause non-negligible corrections to the cross sections for lepton pair annihilation and small corrections for ZZ fusion, and this effect is negligible for WW fusion.
Pair correlations in nuclei involved in neutrinoless double beta decay: 76Ge and 76Se
S. J. Freeman; J. P. Schiffer; A. C. C. Villari; J. A. Clark; C. Deibel; S. Gros; A. Heinz; D. Hirata; C. L. Jiang; B. P. Kay; A. Parikh; P. D. Parker; J. Qian; K. E. Rehm; X. D. Tang; V. Werner; C. Wrede
2007-03-23T23:59:59.000Z
Precision measurements were carried out to test the similarities between the ground states of 76Ge and 76Se. The extent to which these two nuclei can be characterized as consisting of correlated pairs of neutrons in a BCS-like ground state was studied. The pair removal (p,t) reaction was measured at the far forward angle of 3 degrees. The relative cross sections are consistent (at the 5% level) with the description of these nuclei in terms of a correlated pairing state outside the N=28 closed shells with no pairing vibrations. Data were also obtained for 74Ge and 78Se.
E-Print Network 3.0 - atom-photon pair laser Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
quantum communication and a first... pairs of counterpropagating laser beams for optical cooling. Fluorescence light is collected... photon 5 . This kind of atom-photon...
Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas
Y. H. Pong; C. K. Law
2006-05-08T23:59:59.000Z
We examine the basic mode structure of atomic Cooper pairs in an inhomogeneous Fermi gas. Based on the properties of Bogoliubov quasi-particle vacuum, the single particle density matrix and the anomalous density matrix share the same set of eigenfunctions. These eigenfunctions correspond to natural pairing orbits associated with the BCS ground state. We investigate these orbits for a Fermi gas in a spherical harmonic trap, and construct the wave function of a Cooper pair in the form of Schmidt decomposition. The issue of spatial quantum entanglement between constituent atoms in a pair is addressed.
Neutrino-pair bremsstrahlung by electrons in neutron star crusts
A. D. Kaminker; C. J. Pethick; A. Y. Potekhin; V. Thorsson; D. G. Yakovlev
1998-12-25T23:59:59.000Z
Neutrino-pair bremsstrahlung by relativistic degenerate electrons in a neutron-star crust at densities (10^9 - 1.5x10^{14}) g/cm^3 is analyzed. The processes taken into account are neutrino emission due to Coulomb scattering of electrons by atomic nuclei in a Coulomb liquid, and electron-phonon scattering and Bragg diffraction (the static-lattice contribution) in a Coulomb crystal. The static-lattice contribution is calculated including the electron band-structure effects for cubic Coulomb crystals of different types and also for the liquid crystal phases composed of rod- and plate-like nuclei in the neutron-star mantle (at 10^{14} - 1.5x10^{14} g/cm^3). The phonon contribution is evaluated with proper treatment of the multi-phonon processes which removes a jump in the neutrino bremsstrahlung emissivity at the melting point obtained in previous works. Below 10^{13} g/cm^3, the results are rather insensitive to the nuclear form factor, but results for the solid state near the melting point are affected significantly by the Debye-Waller factor and multi-phonon processes. At higher densities, the nuclear form factor becomes more significant. A comparison of the various neutrino generation mechanisms in neutron star crusts shows that electron bremsstrahlung is among the most important ones.
Top Quark Properties from Top Pair Events and Decays
Andrew G. Ivanov; for the CDF; Dzero Collaborations
2008-10-19T23:59:59.000Z
Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and Dzero data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that could be manifested through subtle deviations from the standard model in the production and decays of top quarks. In the following we present a slice of the rich program in top quark physics at the Fermilab Tevatron: measurements of the properties of top quark decays and searches for unusual phenomena in events with pair produced tops. In particular, we discuss the most recent and precise CDF and Dzero measurements of the transverse polarization of W bosons from top decays, branching ratios and searches for flavor-changing neutral current decays, decays into charged Higgs and invisible decays. These analyses correspond to integrated luminosities ranging from 0.9 to 2.7 inv. fb.
The Drinfel'd polynomial of a tridiagonal pair
Ito, Tatsuro
2008-01-01T23:59:59.000Z
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \\to V$ and $A^*:V \\to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; (ii) there exists an ordering $\\{V_i\\}{i=0}^d$ of the eigenspaces of $A$ such that $A^* V_i \\subseteq V_{i-1} + V_{i} + V_{i+1}$ for $0 \\leq i \\leq d$, where $V_{-1}=0$ and $V_{d+1}=0$; (iii) there exists an ordering $\\{V^*_i\\}{i=0}^\\delta$ of the eigenspaces of $A^*$ such that $A V^*_i \\subseteq V^*_{i-1} + V^*_{i} + V^*_{i+1}$ for $0 \\leq i \\leq \\delta$, where $V^*_{-1}=0$ and $V^*_{\\delta+1}=0$; (iv) there is no subspace $W$ of $V$ such that $AW \\subseteq W$, $A^* W \\subseteq W$, $W \
Modeling exclusive meson pair production at hadron colliders
L. A. Harland-Lang; V. A. Khoze; M. G. Ryskin
2014-07-21T23:59:59.000Z
We present a study of the central exclusive production of light meson pairs, concentrating on the region of lower invariant masses of the central system and/or meson transverse momentum, where perturbative QCD cannot be reliably applied. We describe in detail a phenomenological model, using the tools of Regge theory, that may be applied with some success in this regime, and we present the new, publicly available, Dime Monte Carlo (MC) implementation of this for $\\pi\\pi$, $KK$ and $\\rho\\rho$ production. The MC includes a fully differential treatment of the survival factor, which in general depends on all kinematic variables, as well as allowing for the so far reasonably unconstrained model parameters to be set by the user. We present predictions for the Tevatron and LHC and show how future measurements may further test this Regge--based approach, as well as the soft hadronic model required to calculate the survival factor, in particular in the presence of tagged protons.
Space qualified nanosatellite electronics platform for photon pair experiments
Cheng, Cliff; Tan, Yue Chuan; Ling, Alexander
2015-01-01T23:59:59.000Z
We report the design and implementation of a complete electronics platform for conducting a quantum optics experiment that will be operated on board a 1U CubeSat (a 10 x 10 x 10 cm satellite). The quantum optics experiment is designed to produce polarization-entangled photon pairs using non-linear optical crystals and requires opto-electronic components such as a pump laser, single photon detectors and liquid crystal based polarization rotators in addition to passive optical elements. The platform provides mechanical support for the optical assembly. It also communicates autonomously with the host satellite to provide experiment data for transmission to a ground station. A limited number of commands can be transmitted from ground to the platform enabling it to switch experimental modes. This platform requires less than 1.5W for all operations, and is space qualified. The implementation of this electronics platform is a major step on the road to operating quantum communication experiments using nanosatellites.
Space qualified nanosatellite electronics platform for photon pair experiments
Cliff Cheng; Rakhitha Chandrasekara; Yue Chuan Tan; Alexander Ling
2015-05-25T23:59:59.000Z
We report the design and implementation of a complete electronics platform for conducting a quantum optics experiment that will be operated on board a 1U CubeSat (a 10 x 10 x 10 cm satellite). The quantum optics experiment is designed to produce polarization-entangled photon pairs using non-linear optical crystals and requires opto-electronic components such as a pump laser, single photon detectors and liquid crystal based polarization rotators in addition to passive optical elements. The platform provides mechanical support for the optical assembly. It also communicates autonomously with the host satellite to provide experiment data for transmission to a ground station. A limited number of commands can be transmitted from ground to the platform enabling it to switch experimental modes. This platform requires less than 1.5W for all operations, and is space qualified. The implementation of this electronics platform is a major step on the road to operating quantum communication experiments using nanosatellites.
Induction logging device with a pair of mutually perpendicular bucking coils
Koelle, Alfred R. (Los Alamos, NM); Landt, Jeremy A. (Los Alamos, NM)
1981-01-01T23:59:59.000Z
An instrument is disclosed for mapping vertical conductive fractures in a resistive bedrock, magnetically inducing eddy currents by a pair of vertically oriented, mutually perpendicular, coplanar coils. The eddy currents drive magnetic fields which are picked up by a second, similar pair of coils.
Bose-Einstein correlations in K K pairs from Z 0 decays into two hadronic jets
Bose-Einstein correlations in K #6; K #6; pairs from Z 0 decays into two hadronic jets The OPAL collaboration Abstract Bose-Einstein correlations in pairs of charged kaons produced in a sample of 3.9 million function. The parameters of the Bose- Einstein correlations were measured to be #21; = 0.82 #6; 0.22 + 0
Differential top pair cross section and top anti-top plus jets Physics
Malgorzata Worek
2013-02-14T23:59:59.000Z
A brief summary of the current status of the next-to-leading order QCD corrections to top quark pair production and the associated production of top anti-top with jet(s) in different configurations, i.e. with one jet, two jets and another top anti-top pair, is presented.
Universal Design Rules from Product Pairs and Association Rule Based Learning
Cowen, Nicholas L.
2010-07-14T23:59:59.000Z
A product pair is two products with similar functionality that satisfy the same high level need but are different by design. The goal of this research is to apply association rule-based learning to product pairs and develop universal design rules...
Methods and composition for the production of orthogonal tRNA-aminoacyltRNA synthetase pairs
Schultz, Peter G. (La Jolla, CA); Wang, Lei (San Diego, CA); Anderson, John Christopher (San Diego, CA); Chin, Jason (Cambridge, GB); Liu, David R. (Lexington, MA); Magliery, Thomas J. (North Haven, CT); Meggers, Eric L. (Philadelphia, PA); Mehl, Ryan Aaron (Lancaster, PA); Pastrnak, Miro (San Diego, CA); Santoro, Steven William (Cambridge, MA); Zhang, Zhiwen (San Diego, CA)
2012-05-22T23:59:59.000Z
This invention provides compositions and methods for generating components of protein biosynthetic machinery including orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases. Methods for identifying orthogonal pairs are also provided. These components can be used to incorporate unnatural amino acids into proteins in vivo.
EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION
Herbordt, Martin
EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION Matt Chiu ABSTRACT The acceleration of molecular dynamics (MD) simulations using high performance reconfigurable: determining the short-range force between particle pairs. In particular, we present the first FPGA study
A Paired-Vehicle Recourse Strategy for the Vehicle Routing Problem with Stochastic Demands
Erera, Alan
A Paired-Vehicle Recourse Strategy for the Vehicle Routing Problem with Stochastic Demands Aykagan Institute of Technology Abstract This paper presents a paired-vehicle recourse strategy for the vehicle vehicles is dispatched from a terminal to serve single-period customer demands which are known
Flexibility of short DNA helices with finite-length effect: from base pairs to tens of base pairs
Wu, Yuan-Yan; Zhang, Xi; Tan, Zhi-Jie
2015-01-01T23:59:59.000Z
Flexibility of short DNA helices is important for the biological functions such as nucleosome formation and DNA-protein recognition. Recent experiments suggest that short DNAs of tens of base pairs (bps) may have apparently higher flexibility than those of kilo bps, while there is still the debate on such high flexibility. In the present work, we have studied the flexibility of short DNAs with finite-length of 5 to 50 bps by the all-atomistic molecular dynamics simulations and Monte Carlo simulations with the worm-like chain model. Our microscopic analyses reveal that short DNAs have apparently high flexibility which is attributed to the significantly strong bending and stretching flexibilities of ~6 bps at each helix end. Correspondingly, the apparent persistence length lp of short DNAs increases gradually from ~29nm to ~45nm as DNA length increases from 10 to 50 bps, in accordance with the available experimental data. Our further analyses show that the short DNAs with excluding ~6 bps at each helix end have...
A weak-value interpretation of the Schwinger mechanism of massless/massive pair productions
Kazuhiro Yokota; Nobuyuki Imoto
2015-04-28T23:59:59.000Z
According to the Schwinger mechanism, a uniform electric field brings about pair productions in vacuum; the relationship between the production rate and the electric field is different, depending on the dimension of the system. In this paper, we make an offer of another model for the pair productions, in which weak values are incorporated: energy fluctuations trigger the pair production, and a weak value appears as the velocity of a particle there. Although our model is only available for the approximation of the pair production rates, the weak value reveals a new aspect of the pair production. Especially, within the first order, our estimation approximately agrees with the exponential decreasing rate of the Landau-Zener tunneling through the mass energy gap. In other words, such tunneling can be associated with energy fluctuations via the weak value, when the tunneling gap can be regarded as so small due to the high electric field.
The Radical Pair Mechanism and the Avian Chemical Compass: Quantum Coherence and Entanglement
Zhang, Yiteng; Kais, Sabre
2015-01-01T23:59:59.000Z
We review the spin radical pair mechanism which is a promising explanation of avian navigation. This mechanism is based on the dependence of product yields on (1) the hyperfine interaction involving electron spins and neighboring nuclear spins and (2) the intensity and orientation of the geomagnetic field. One surprising result is that even at ambient conditions quantum entanglement of electron spins can play an important role in avian magnetoreception. This review describes the general scheme of chemical reactions involving radical pairs generated from singlet and triplet precursors; the spin dynamics of the radical pairs; and the magnetic field dependence of product yields caused by the radical pair mechanism. The main part of the review includes a description of the chemical compass in birds. We review: the general properties of the avian compass; the basic scheme of the radical pair mechanism; the reaction kinetics in cryptochrome; quantum coherence and entanglement in the avian compass; and the effects o...
Origin of the low-mass electron pair excess in light nucleus-nucleus collisions
The HADES Collaboration; G. Agakishiev; A. Balanda; D. Belver; A. V. Belyaev; A. Blanco; M. Bhmer; J. L. Boyard; P. Braun-Munzinger; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Daz; F. Dohrmann; A. Dybczak; L. Fabbietti; O. V. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Frhlich; T. Galatyuk; J. A. Garzn; R. Gernhuser; A. Gil; C. Gilardi; M. Golubeva; D. Gonzlez-Daz; F. Guber; T. Hennino; R. Holzmann; I. Iori; A. Ivashkin; M. Jurkovic; B. Kmpfer; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; F. Krizek; R. Krcken; W. Khn; A. Kugler; A. Kurepin; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Markert; V. Metag; B. Michalska; J. Michel; E. Morinire; J. Mousa; C. Mntz; L. Naumann; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; A. Rustamov; A. Sadovsky; P. Salabura; A. Schmah; E. Schwab; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Strbele; J. Stroth; C. Sturm; M. Sudol; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; V. Wagner; M. Weber; M. Wisniowski; T. Wojcik; J. Wstenfeld; S. Yurevich; Y. V. Zanevsky; P. Zhou
2009-10-30T23:59:59.000Z
We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n+p reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e- > 0.15 GeV/c2 is about an order of magnitude larger in n+p reactions as compared to p+p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C+C reactions are compatible with a superposition of elementary n+p and p+p collisions, leaving little room for additional electron pair sources in such light collision systems.
Pair distribution function study on compression of liquid gallium
Luo, Shengnian [Los Alamos National Laboratory; Yu, Tony [SUNY-SB; Chen, Jiuhua [SUNY-SB; Ehm, Lars [SUNY-SB; Guo, Quanzhong [SUNY-SB; Parise, John [SUNY-SB
2008-01-01T23:59:59.000Z
Integrating a hydrothermal diamond anvil cell (HDAC) and focused high energy x-ray beam from the superconductor wiggler X17 beamline at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL), we have successfully collected high quality total x-ray scattering data of liquid gallium. The experiments were conducted at a pressure range from 0.1GPa up to 2GPa at ambient temperature. For the first time, pair distribution functions (PDF) for liquid gallium at high pressure were derived up to 10 {angstrom}. Liquid gallium structure has been studied by x-ray absorption (Di Cicco & Filipponi, 1993; Wei et al., 2000; Comez et al., 2001), x-ray diffraction studies (Waseda & Suzuki, 1972), and molecular dynamics simulation (Tsay, 1993; Hui et al., 2002). These previous reports have focused on the 1st nearest neighbor structure, which tells us little about the atomic arrangement outside the first shell in non- crystalline materials. This study focuses on the structure of liquid gallium and the atomic structure change due to compression. The PDF results show that the observed atomic distance of the first nearest neighbor at 2.78 {angstrom} (first G(r) peak and its shoulder at the higher Q position) is consistent with previous studies by x-ray absorption (2.76 {angstrom}, Comez et al., 2001). We have also observed that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of 'locally rigid units' in the liquid. With the addition of reverse Monte Carlo modeling, we have observed that the coordination number in the local rigit unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature (300K) is 12.1(6) GPa.
MULTI-DIMENSIONAL SIMULATIONS OF ROTATING PAIR-INSTABILITY SUPERNOVAE
Chatzopoulos, E.; Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Couch, Sean M., E-mail: manolis@astro.as.utexas.edu [Department of Astronomy and Astrophysics, Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States)
2013-10-20T23:59:59.000Z
We study the effects of rotation on the dynamics, energetics, and {sup 56}Ni production of pair instability supernova (PISN) explosions by performing rotating two-dimensional ({sup 2}.5D{sup )} hydrodynamics simulations. We calculate the evolution of eight low-metallicity (Z = 10{sup 3}, 10{sup 4} Z{sub ?}) massive (135-245 M{sub ?}) PISN progenitors with initial surface rotational velocities of 50% of the critical Keplerian value using the stellar evolution code MESA. We allow for both the inclusion and the omission of the effects of magnetic fields in the angular momentum transport and in chemical mixing, resulting in slowly rotating and rapidly rotating final carbon-oxygen cores, respectively. Increased rotation for carbon-oxygen cores of the same mass and chemical stratification leads to less energetic PISN explosions that produce smaller amounts of {sup 56}Ni due to the effect of the angular momentum barrier that develops and slows the dynamical collapse. We find a non-monotonic dependence of {sup 56}Ni production on rotational velocity in situations when smoother composition gradients form at the outer edge of the rotating cores. In these cases, the PISN energetics are determined by the competition of two factors: the extent of chemical mixing in the outer layers of the core due to the effects of rotation in the progenitor evolution and the development of angular momentum support against collapse. Our 2.5D PISN simulations with rotation are the first presented in the literature. They reveal hydrodynamic instabilities in several regions of the exploding star and increased explosion asymmetries with higher core rotational velocity.
Measurements of Baryon Pair Decays of $?_{cJ}$ Mesons
M. Ablikim; M. N. Achasov; O. Albayrak; D. J. Ambrose; F. F. An; Q. An; J. Z. Bai; Y. Ban; J. Becker; J. V. Bennett; M. Bertani; J. M. Bian; E. Boger; O. Bondarenko; I. Boyko; R. A. Briere; V. Bytev; X. Cai; O. Cakir; A. Calcaterra; G. F. Cao; S. A. Cetin; J. F. Chang; G. Chelkov; G. Chen; H. S. Chen; J. C. Chen; M. L. Chen; S. J. Chen; X. Chen; Y. B. Chen; H. P. Cheng; Y. P. Chu; D. Cronin-Hennessy; H. L. Dai; J. P. Dai; D. Dedovich; Z. Y. Deng; A. Denig; I. Denysenko; M. Destefanis; W. M. Ding; Y. Ding; L. Y. Dong; M. Y. Dong; S. X. Du; J. Fang; S. S. Fang; L. Fava; C. Q. Feng; R. B. Ferroli; P. Friedel; C. D. Fu; Y. Gao; C. Geng; K. Goetzen; W. X. Gong; W. Gradl; M. Greco; M. H. Gu; Y. T. Gu; Y. H. Guan; A. Q. Guo; L. B. Guo; T. Guo; Y. P. Guo; Y. L. Han; F. A. Harris; K. L. He; M. He; Z. Y. He; T. Held; Y. K. Heng; Z. L. Hou; C. Hu; H. M. Hu; J. F. Hu; T. Hu; G. M. Huang; G. S. Huang; J. S. Huang; L. Huang; X. T. Huang; Y. Huang; Y. P. Huang; T. Hussain; C. S. Ji; Q. Ji; Q. P. Ji; X. B. Ji; X. L. Ji; L. L. Jiang; X. S. Jiang; J. B. Jiao; Z. Jiao; D. P. Jin; S. Jin; F. F. Jing; N. Kalantar-Nayestanaki; M. Kavatsyuk; B. Kopf; M. Kornicer; W. Kuehn; W. Lai; J. S. Lange; M. Leyhe; C. H. Li; Cheng Li; Cui Li; D. M. Li; F. Li; G. Li; H. B. Li; J. C. Li; K. Li; Lei Li; Q. J. Li; S. L. Li; W. D. Li; W. G. Li; X. L. Li; X. N. Li; X. Q. Li; X. R. Li; Z. B. Li; H. Liang; Y. F. Liang; Y. T. Liang; G. R. Liao; X. T. Liao; D. Lin; B. J. Liu; C. L. Liu; C. X. Liu; F. H. Liu; Fang Liu; Feng Liu; H. Liu; H. B. Liu; H. H. Liu; H. M. Liu; H. W. Liu; J. P. Liu; K. Liu; K. Y. Liu; Kai Liu; P. L. Liu; Q. Liu; S. B. Liu; X. Liu; Y. B. Liu; Z. A. Liu; Zhiqiang Liu; Zhiqing Liu; H. Loehner; G. R. Lu; H. J. Lu; J. G. Lu; Q. W. Lu; X. R. Lu; Y. P. Lu; C. L. Luo; M. X. Luo; T. Luo; X. L. Luo; M. Lv; C. L. Ma; F. C. Ma; H. L. Ma; Q. M. Ma; S. Ma; T. Ma; X. Y. Ma; F. E. Maas; M. Maggiora; Q. A. Malik; Y. J. Mao; Z. P. Mao; J. G. Messchendorp; J. Min; T. J. Min; R. E. Mitchell; X. H. Mo; C. Morales Morales; N. Yu. Muchnoi; H. Muramatsu; Y. Nefedov; C. Nicholson; I. B. Nikolaev; Z. Ning; S. L. Olsen; Q. Ouyang; S. Pacetti; J. W. Park; M. Pelizaeus; H. P. Peng; K. Peters; J. L. Ping; R. G. Ping; R. Poling; E. Prencipe; M. Qi; S. Qian; C. F. Qiao; L. Q. Qin; X. S. Qin; Y. Qin; Z. H. Qin; J. F. Qiu; K. H. Rashid; G. Rong; X. D. Ruan; A. Sarantsev; B. D. Schaefer; M. Shao; C. P. Shen; X. Y. Shen; H. Y. Sheng; M. R. Shepherd; X. Y. Song; S. Spataro; B. Spruck; D. H. Sun; G. X. Sun; J. F. Sun; S. S. Sun; Y. J. Sun; Y. Z. Sun; Z. J. Sun; Z. T. Sun; C. J. Tang; X. Tang; I. Tapan; E. H. Thorndike; D. Toth; M. Ullrich; G. S. Varner; B. Q. Wang; D. Wang; D. Y. Wang; K. Wang; L. L. Wang; L. S. Wang; M. Wang; P. Wang; P. L. Wang; Q. J. Wang; S. G. Wang; X. F. Wang; X. L. Wang; Y. F. Wang; Z. Wang; Z. G. Wang; Z. Y. Wang; D. H. Wei; J. B. Wei; P. Weidenkaff; Q. G. Wen; S. P. Wen; M. Werner; U. Wiedner; L. H. Wu; N. Wu; S. X. Wu; W. Wu; Z. Wu; L. G. Xia; Z. J. Xiao; Y. G. Xie; Q. L. Xiu; G. F. Xu; G. M. Xu; Q. J. Xu; Q. N. Xu; X. P. Xu; Z. R. Xu; F. Xue; Z. Xue; L. Yan; W. B. Yan; Y. H. Yan; H. X. Yang; Y. Yang; Y. X. Yang; H. Ye; M. Ye; M. H. Ye; B. X. Yu; C. X. Yu; H. W. Yu; J. S. Yu; S. P. Yu; C. Z. Yuan; Y. Yuan; A. A. Zafar; A. Zallo; Y. Zeng; B. X. Zhang; B. Y. Zhang; C. Zhang; C. C. Zhang; D. H. Zhang; H. H. Zhang; H. Y. Zhang; J. Q. Zhang; J. W. Zhang; J. Y. Zhang; J. Z. Zhang; R. Zhang; S. H. Zhang; X. J. Zhang; X. Y. Zhang; Y. Zhang; Y. H. Zhang; Z. P. Zhang; Z. Y. Zhang; Zhenghao Zhang; G. Zhao; H. S. Zhao; J. W. Zhao; K. X. Zhao; Lei Zhao; Ling Zhao; M. G. Zhao; Q. Zhao; Q. Z. Zhao; S. J. Zhao; T. C. Zhao; Y. B. Zhao; Z. G. Zhao; A. Zhemchugov; B. Zheng; J. P. Zheng; Y. H. Zheng; B. Zhong; Z. Zhong; L. Zhou; X. K. Zhou; X. R. Zhou; C. Zhu; K. Zhu; K. J. Zhu; S. H. Zhu; X. L. Zhu; Y. C. Zhu; Y. M. Zhu; Y. S. Zhu; Z. A. Zhu; J. Zhuang; B. S. Zou; J. H. Zou
2013-03-05T23:59:59.000Z
Using 106 $\\times 10^{6}$ $\\psi^{\\prime}$ decays collected with the BESIII detector at the BEPCII, three decays of $\\chi_{cJ}$ ($J=0,1,2$) with baryon pairs ($\\llb$, $\\ssb$, $\\SSB$) in the final state have been studied. The branching fractions are measured to be $\\cal{B}$$(\\chi_{c0,1,2}\\rightarrow\\Lambda\\bar\\Lambda) =(33.3 \\pm 2.0 \\pm 2.6)\\times 10^{-5}$, $(12.2 \\pm 1.1 \\pm 1.1)\\times 10^{-5}$, $(20.8 \\pm 1.6 \\pm 2.3)\\times 10^{-5}$; $\\cal{B}$$(\\chi_{c0,1,2}\\rightarrow\\Sigma^{0}\\bar\\Sigma^{0})$ = $(47.8 \\pm 3.4 \\pm 3.9)\\times 10^{-5}$, $(3.8 \\pm 1.0 \\pm 0.5)\\times 10^{-5}$, $(4.0 \\pm 1.1 \\pm 0.5) \\times 10^{-5}$; and $\\cal{B}$$(\\chi_{c0,1,2}\\rightarrow\\Sigma^{+}\\bar\\Sigma^{-})$ = $(45.4 \\pm 4.2 \\pm 3.0)\\times 10^{-5}$, $(5.4 \\pm 1.5 \\pm 0.5)\\times 10^{-5}$, $(4.9 \\pm 1.9 \\pm 0.7)\\times 10^{-5}$, where the first error is statistical and the second is systematic. Upper limits on the branching fractions for the decays of $\\chi_{c1,2}\\rightarrow\\Sigma^{0}\\bar\\Sigma^{0}$, $\\Sigma^{+}\\bar\\Sigma^{-}$, are estimated to be $\\cal{B}$$(\\chi_{c1}\\rightarrow\\Sigma^{0}\\bar\\Sigma^{0}) < 6.2\\times 10^{-5}$, $\\cal{B}$$(\\chi_{c2}\\rightarrow\\Sigma^{0}\\bar\\Sigma^{0}) < 6.5\\times 10^{-5}$, $\\cal{B}$$(\\chi_{c1}\\rightarrow\\Sigma^{+}\\bar\\Sigma^{-}) < 8.7\\times 10^{-5}$ and $\\cal{B}$$(\\chi_{c2}\\rightarrow\\Sigma^{+}\\bar\\Sigma^{-}) < 8.8\\times 10^{-5}$ at the 90% confidence level.
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Competing Pairing Symmetries in a Generalized Two-Orbital Model for the Pnictide Superconductors
Nicholson, Andrew D [ORNL; Ge, Weihao [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Zhang, Xiaotian [Oak Ridge National Laboratory (ORNL); Riera, J. A. [Universidad Nacional de Rosario; Daghofer, M. [IFW Dresden; Ols, Andrzej M. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Martins, G. B. [Oakland University, Rochester, MI; Moreo, Adriana [ORNL; Dagotto, Elbio R [ORNL
2011-01-01T23:59:59.000Z
We introduce and study an extended t-U-J two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms explicitly allows us to enhance the strength of the %;0 - 0;% spin order which favors the presence of tightly bound pairing states even in the small clusters that are here exactly diagonalized. The A1g and B2g pairing symmetries are found to compete in the realistic spin-ordered and metallic regime. The dynamical pairing susceptibility additionally unveils low-lying B1g states, suggesting that small changes in parameters may render any of the three channels stable.
Distribution of Primes and of Interval Prime Pairs Based on $?$ Function
Yifang Fan; Zhiyu Li
2010-04-19T23:59:59.000Z
$\\Theta$ function is defined based upon Kronecher symbol. In light of the principle of inclusion-exclusion, $\\Theta$ function of sine function is used to denote the distribution of composites and primes. The structure of Goldbach Conjecture has been analyzed, and $\\Xi$ function is brought forward by the linear diophantine equation; by relating to $\\Theta$ function, the interval distribution of composite pairs and prime pairs (i.e. the Goldbach Conjecture) is thus obtained. In the end, Abel's Theorem (Multiplication of Series) is used to discuss the lower limit of the distribution of the interval prime pairs.
Shenanigans at the black hole horizon: pair creation or Boulware accretion?
Israel, Werner
2015-01-01T23:59:59.000Z
The current scenario of black hole evaporation holds that the Hawking energy flux $F$ is powered by pair creation at the horizon. However, pair creation produces entanglements, some of which must necessarily be broken before the black hole evaporates completely. That leads to loss of information and violation of unitarity. In this paper, an alternative scenario is suggested that reproduces the essential features of Hawking evaporation, but does not invoke pair creation with its attendant problems. In this "accreting Boulware" scenario, a positive flux $F$ is still an outflux at infinity, but near the horizon it becomes an influx of negative energy. This negative energy flux (marginally) satisfies the Flanagan energy inequality.
Geometric Origin of Pair Production by Electric Field in de Sitter Space
Sang Pyo Kim
2014-04-15T23:59:59.000Z
The particle production in a de Sitter space provides an interesting model to understand the curvature effect on Schwinger pair production by a constant electric field or Schwinger mechanism on the de Sitter radiation. For that purpose, we employ the recently introduced complex analysis method, in which the quantum evolution in the complex time explains the pair production via the geometric transition amplitude and gives the pair-production rate as the contour integral. We compare the result by the contour integral with that of the phase-integral method.
Non-Archimedian integrals and stringy Euler numbers of log terminal pairs
Victor V. Batyrev
1998-03-16T23:59:59.000Z
Using non-Archimedian integration over spaces of arcs of algebraic varieties, we define stringy Euler numbers associated with arbitrary Kawamata log terminal pairs. There is a natural Kawamata log terminal pair corresponding to an algebraic variety V having a regular action of a finite group G. In this situation we show that the stringy Euler number of this pair coincides with the physicists' orbifold Euler number defined by the Dixon-Harvey-Vafa-Witten formula. As an application, we prove a conjecture of Miles Reid on the Euler numbers of crepant desingularizations of Gorenstein quotient singularities.
PHYSICAL REVIEW B 86, 195103 (2012) Dynamics of doublon-holon pairs in Hubbard two-leg ladders
Dias, Luis Gregório
PHYSICAL REVIEW B 86, 195103 (2012) Dynamics of doublon-holon pairs in Hubbard two-leg ladders Luis of holon-doublon pairs is studied in Hubbard two-leg ladders using the time-dependent density matrix of a doublon-holon pair. Two distinct regimes are identified. For weak interleg coupling, the results
Choi, Mahn-Soo
2014-01-01T23:59:59.000Z
PHYSICAL REVIEW B 89, 045137 (2014) Hanbury Brown and Twiss correlations of Cooper pairs in helical; published 29 January 2014) We propose a Hanbury Brown and Twiss (HBT) experiment of Cooper pairs on the edge a Hanbury Brown and Twiss (HBT) experiment of Cooper pairs on the edge channels of quantum spin Hall
A. V. Borisov; P. E. Sizin
2014-06-12T23:59:59.000Z
We calculate the neutrino luminosity of a degenerate electron gas in a strong magnetic field via plasmon decay to a neutrino pair due to neutrino electromagnetic moments and obtain the relative upper bounds on the effective neutrino magnetic moment.
WHEN A PAIR of nuclear-powered Russian submarines was reported patrolling
California at Los Angeles, University of
WHEN A PAIR of nuclear-powered Russian submarines was reported patrolling off the eastern seaboard as "explaining-away." Although several algorithms were later developed to perform Bayesian updating in general
Thesis for the Degree of Licentiate of Philosophy TwoLocus Affected SibPair
Patriksson, Michael
Thesis for the Degree of Licentiate of Philosophy TwoLocus Affected SibPair Identity By Descenttime arrangement. This licentiate thesis has been financially supported by the National Network in Applied
Study of nuclear pairing with Configuration-Space Monte-Carlo approach
Lingle, Mark
2015-01-01T23:59:59.000Z
Pairing correlations in nuclei play a decisive role in determining nuclear drip-lines, binding energies, and many collective properties. In this work a new Configuration-Space Monte-Carlo (CSMC) method for treating nuclear pairing correlations is developed, implemented, and demonstrated. In CSMC the Hamiltonian matrix is stochastically generated in Krylov subspace, resulting in the Monte-Carlo version of Lanczos-like diagonalization. The advantages of this approach over other techniques are discussed; the absence of the fermionic sign problem, probabilistic interpretation of quantum-mechanical amplitudes, and ability to handle truly large-scale problems with defined precision and error control, are noteworthy merits of CSMC. The features of our CSMC approach are shown using models and realistic examples. Special attention is given to difficult limits: situations with non-constant pairing strengths, cases with nearly degenerate excited states, limits when pairing correlations in finite systems are weak, and pr...
Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B; Luebke, David R.; Damodaran, Krishnan
2013-04-24T23:59:59.000Z
Density Functional Theory is used to investigate a weakly coordinating room-temperature ionic liquid, 1-ethyl-3-methyl imidazolium tetracyanoborate ([Emim]{sup +}[TCB]{sup -}). Four locally stable conformers of the ion pair were located. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of several hydrogen bonds. Further investigation through the Natural Bond Orbital (NBO) and Natural Energy Decomposition Analysis (NEDA) calculations provided insight into the origin of interactions in the [Emim]{sup +}[TCB]{sup -} ion pair. Strength of molecular interactions in the ionic liquid was correlated with frequency shifts of the characteristic vibrations of the ion pair. Harmonic vibrations of the ion pair were also compared with the experimental Raman and Infrared spectra. Vibrational frequencies were assigned by visualizing displacements of atoms around their equilibrium positions and through Potential Energy Distribution (PED) analysis.
INTRODUCTION Meiosis is the specialized pair of cell divisions that normally
Bass, Hank W.
(FISH) were used to localize a single pair of homologs in diploid nuclei of a chromosome-addition line of FISH signals. Using a triple labeling scheme for simultaneous imaging of chromatin, telomeres Hank W. Bass1,2,*, Osc
Formation of O Adatom Pairs and Charge Transfer upon O-2 Dissociation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
details of O2 dissociation leading to the formation of oxygen adatom (Oa) pairs at terminal Ti sites. An intermediate, metastable Oa-Oa configuration with two nearest-neighbor O...
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay Universit??e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 F38402 SaintMartind'H??eres, France Thierry.Gallay
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay Universit´e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 F-38402 Saint-Martin-d'H`eres, France Thierry.Gallay
Pairing preferences of the model mono-valence mono-atomic ions investigated by molecular simulation
Zhang, Qiang [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China) [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Department of Chemistry, Bohai University, Jinzhou 121000 (China); Zhang, Ruiting; Zhao, Ying; Li, HuanHuan; Zhuang, Wei, E-mail: wzhuang@dicp.ac.cn, E-mail: gaoyq@pku.edu.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China)] [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Gao, Yi Qin, E-mail: wzhuang@dicp.ac.cn, E-mail: gaoyq@pku.edu.cn [College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871 (China)
2014-05-14T23:59:59.000Z
We carried out a series of potential of mean force calculations to study the pairing preferences of a series of model mono-atomic 1:1 ions with evenly varied sizes. The probabilities of forming the contact ion pair (CIP) and the single water separate ion pair (SIP) were presented in the two-dimensional plots with respect to the ion sizes. The pairing preferences reflected in these plots largely agree with the empirical rule of matching ion sizes in the small and big size regions. In the region that the ion sizes are close to the size of the water molecule; however, a significant deviation from this conventional rule is observed. Our further analysis indicated that this deviation originates from the competition between CIP and the water bridging SIP state. The competition is mainly an enthalpy modulated phenomenon in which the existing of the water bridging plays a significant role.
Pair correlations in the neutrinoless double-{beta} decay candidate {sup 130}Te
Bloxham, T.; Freedman, S. J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kay, B. P.; Schiffer, J. P.; Clark, J. A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Deibel, C. M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48825 (United States); Freeman, S. J.; Howard, A. M.; McAllister, S. A.; Sharp, D. K.; Thomas, J. S. [Schuster Laboratory, University of Manchester, Manchester, M13 9PL (United Kingdom); Parker, P. D. [A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States)
2010-08-15T23:59:59.000Z
Pair correlations in the ground state of {sup 130}Te have been investigated using pair-transfer experiments to explore the validity of approximations in calculating the matrix element for neutrinoless double-{beta} decay. This nucleus is a candidate for the observation of such decay, and a good understanding of its structure is crucial for eventual calculations of the neutrino mass, should such a decay indeed be observed. For proton-pair adding, strong transitions to excited 0{sup +} states had been observed in the Te isotopes by Alford et al. [Nucl. Phys. A 323, 339 (1979)], indicating a breaking of the BCS approximation for protons in the ground state. We measured the neutron-pair removing (p,t) reaction on {sup 130}Te and found no indication of a corresponding splitting of the BCS nature of the ground state for neutrons.
Pair correlations in neutrinoless double {beta} decay candidate {sup 130}Te.
Bloxham, T.; Kay, B. P.; Schiffer, J. P.; Clark, J. A.; Deibel, C. M.; Freeman, S. J.; Freedman, S. J.; Howard, A. M.; McAllister, S. A.; Parker, P. D.; Sharp, D. K.; Thomas, J. S. (Physics); ( PSC-USR); (LBNL); (Michigan State Univ.); (Univ. of Manchester); (Yale Univ.)
2010-08-16T23:59:59.000Z
Pair correlations in the ground state of {sup 130}Te have been investigated using pair-transfer experiments to explore the validity of approximations in calculating the matrix element for neutrinoless double-{beta} decay. This nucleus is a candidate for the observation of such decay, and a good understanding of its structure is crucial for eventual calculations of the neutrino mass, should such a decay indeed be observed. For proton-pair adding, strong transitions to excited 0{sup +} states had been observed in the Te isotopes by Alford et al. [Nucl. Phys. A 323, 339 (1979)], indicating a breaking of the BCS approximation for protons in the ground state. We measured the neutron-pair removing (p,t) reaction on {sup 130}Te and found no indication of a corresponding splitting of the BCS nature of the ground state for neutrons.
Gomez-Ceballos, Guillelmo
We combine six measurements of the inclusive top-quark pair (t[bar over t]) production cross section (?[subscript tt]-) from data collected with the CDF and D0 detectors at the Fermilab Tevatron with proton-antiproton ...
Pairing of valence electrons as necessary condition for energy minimization in a crystal
Dolgopolov Stanislav Olegovich
2014-10-21T23:59:59.000Z
Pairing of valence electrons can lead to energy minimization of a crystal. It can be proved by use of representation of the valence electrons as plane waves in periodic potential of the crystal.
Parallel Assembly of Large Genomes from Paired Short Reads (2010 JGI/ANL HPC Workshop)
Aluru, Srinivas [Iowa State University
2011-06-08T23:59:59.000Z
Srinivas Aluru from Iowa State University gives a presentation on "Parallel Assembly of Large Genomes from Paired Short Reads" at the JGI/Argonne HPC Workshop on January 25, 2010.
Nucleon and nucleon-pair momentum distributions in A?12 nuclei
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wiringa, Robert B. [ANL; Schiavilla, Rocco [ODU, JLAB; Pieper, Steven C. [ANL; Carlson, Joseph A. [LANL
2014-02-01T23:59:59.000Z
We report variational Monte Carlo calculations of single-nucleon momentum distributions for A?12 nuclei and nucleon-pair and nucleon-cluster momentum distributions for A?8. The wave functions have been generated for a Hamiltonian containing the Argonne ?18 two-nucleon and Urbana X three-nucleon potentials. The single-nucleon and nucleon-pair momentum distributions exhibit universal features attributable to the one-pion-exchange tensor interaction The single-nucleon distributions are broken down into proton and neutron components and spin-up and spin-down components where appropriate. The nucleon-pair momentum distributions are given separately for pp and pn pairs. The nucleon-cluster momentum distributions include dp in 3He, tp and dd in S4He, ?d in 6Li,?t in 7Li, and ?? in 8Be. Detailed tables are provided on-line for download.
Towards laser based improved experimental schemes for multiphoton e+ e- pair production from vacuum
I. Ploumistakis; S. D. Moustaizis; I. Tsohantjis
2009-07-15T23:59:59.000Z
Numerical estimates for pair production from vacuum in the presence of strong electromagnetic fields are derived, for two experimental schemes : the First concerns a laser based X-FEL and the other imitates the E144 experiment. The approximation adopted in this work is that of two level multiphoton on resonance. Utilizing achievable values of laser beam parameters, an enhancedproduction efficiency of up to 10^11 and 10^15 pairs can be obtained, for the two schemes respectively.
Relativistic mean field plus exact pairing approach to open shell nuclei
Wei-Chia Chen; J. Piekarewicz; A. Volya
2013-11-20T23:59:59.000Z
Background: Pairing correlations play a critical role in determining numerous properties of open-shell nuclei. Traditionally, they are included in a mean-field description of atomic nuclei through the approximate Bardeen-Cooper-Schrieffer or Hartree-Fock-Bogoliubov formalism. Purpose: We propose a new hybrid ''relativistic-mean-field-plus-pairing'' approach in which pairing is treated exactly so the number of particles is conserved. To verify the reliability of the formalism, we apply it to the study of both ground-state properties and isoscalar monopole excitations of the Tin isotopes. Methods: Accurately-calibrated relativistic mean-field models supplemented by an exact treatment of pairing correlations are used to compute ground-state observables along the isotopic chain in Tin. In turn, ground-state densities are used as input to the calculation of giant monopole resonances through a constrained-relativistic approach. Results: We compute a variety of ground-state observables sensitive to pairing correlations as well as the evolution of giant monopole energies along the isotopic chain in Tin. Whereas ground-state properties are consistent with experiment, we find that pairing correlations have a minor effect on the giant monopole energies. Conclusions: A new mean-field-plus-pairing approach is introduced to compute properties of open-shell nuclei. The formalism provides an efficient and powerful alternative to the computation of both ground-state properties and monopole energies of open-shell nuclei. We find ground-state properties to be well reproduced in this approach. However, as many have concluded before us, we find that pairing correlations are unlikely to provide an answer to the question of ''why is Tin so soft?''
Electron-Positron Pair Production in Space- or Time-Dependent Electric Fields
Hagen Kleinert; Remo Ruffini; She-Sheng Xue
2008-07-06T23:59:59.000Z
Treating the production of electron and positron pairs by a strong electric field from the vacuum as a quantum tunneling process we derive, in semiclassical approximation, a general expression for the pair production rate in a $z$-dependent electric field $E(z)$ pointing in the $z$-direction. We also allow for a smoothly varying magnetic field parallel to $E(z)$. The result is applied to a confined field $E(z)\
Synaptonemal complex analysis of chromosomal pairing in two species of quail
Ryder, Elizabeth Jeanne
1989-01-01T23:59:59.000Z
SYNAPTONEMAL COMPLEX ANALYSIS OF CHROMOSOMAL PAIRING IN TWO SPECIES OF QUAIL A THESIS by ELIZABETH JEANNE RYDER Submitted to the Office of Graduate Studies of Texas A & M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1989 Maj or subj ect: Genetics SYNAPTONEMAL COMPLEX ANALYSIS OF CHROMOSOMAL PAIRING IN TWO SPECIES OF QUAIL A THESIS by ELIZABETH JEANNE RYDER Approved as to style and content by: / '. '/, ( ~ P /, g/? Ira F...
On Evolution of the Pair-Electromagnetic Pulse of a Charge Black Hole
Remo Ruffini; Jay D. Salmonson; James R. Wilson; She-Sheng Xue
1999-05-04T23:59:59.000Z
Using hydrodynamic computer codes, we study the possible patterns of relativistic expansion of an enormous pair-electromagnetic-pulse (P.E.M. pulse); a hot, high density plasma composed of photons, electron-positron pairs and baryons deposited near a charged black hole (EMBH). On the bases of baryon-loading and energy conservation, we study the bulk Lorentz factor of expansion of the P.E.M. pulse by both numerical and analytical methods.
Parity mixing of pair at nuclear surface due to spin-orbit potential in $^{18}$F
Yoshiko Kanada-En'yo; Fumiharu Kobayashi
2014-07-01T23:59:59.000Z
We investigate the structure of $^{18}$F with the microscopic wave function based on the three-body $^{16}$O+$p$+$n$ model. In the calculation of the generator coordinate method (GCM) of the three-body model, $T=0$ energy spectra of $J^\\pi=1^+$, $3^+$, and $5^+$ states and $T=1$ spectra of $J^\\pi=0^+$, $2^+$ states in $^{18}$F are described reasonably. Based on the dinucleon picture, the effect of the spin-orbit force on the $T=0$ and $T=1$ $pn$ pairs around the $^{16}$O core is discussed. The $T=1$ pair in the $J^\\pi=0^+$ state gains the spin-orbit potential energy involving the odd-parity mixing in the pair. The spin-orbit potential energy gain with the parity mixing is not so efficient for the $T=0$ pair in the $J^\\pi=1^+$ state. The parity mixing in the pair is regarded as the internal symmetry breaking of the pair in the spin-orbit potential at the nuclear surface.
Optical Flashes from Internal Pairs Formed in Gamma-Ray Burst Afterglows
Panaitescu, A
2015-01-01T23:59:59.000Z
We develop a numerical formalism for calculating the distribution with energy of the (internal) pairs formed in a relativistic source from unscattered MeV--TeV photons. For GRB afterglows, this formalism is more suitable if the relativistic reverse-shock that energizes the ejecta is the source of the GeV photons. The number of pairs formed is set by the source GeV output (calculated from the Fermi-LAT fluence), the unknown source Lorentz factor, and the unmeasured peak energy of the LAT spectral component. We show synchrotron and inverse-Compton light-curves expected from pairs formed in the shocked medium and identify some criteria for testing a pair origin of GRB optical counterparts. Pairs formed in bright LAT afterglows with a Lorentz factor in the few hundreds may produce bright optical counterparts (R < 10) lasting for up to one hundred seconds. The number of internal pairs formed from unscattered seed photons decreases very strongly with the source Lorentz factor, thus bright GRB optical counterpart...
Electron-positron pair oscillation in spatially inhomogeneous electric fields and radiation
Wen-Biao Han; Remo Ruffini; She-Sheng Xue
2010-06-11T23:59:59.000Z
It is known that strong electric fields produce electron and positron pairs from the vacuum, and due to the back-reaction these pairs oscillate back and forth coherently with the alternating electric fields in time. We study this phenomenon in spatially inhomogeneous and bound electric fields by integrating the equations of energymomentum and particle-number conservations and Maxwell equations. The space and time evolutions of the pair-induced electric field, electric charge- and currentdensities are calculated. The results show that non-vanishing electric charge-density and the propagation of pair-induced electric fields, differently from the case of homogeneous and unbound electric fields. The space and time variations of pair-induced electric charges and currents emit an electromagnetic radiation. We obtain the narrow spectrum and intensity of this radiation, whose peak {\\omega}peak locates in the region around 4 KeV for electric field strength \\sim Ec. We discuss their relevances to both the laboratory experiments for electron and positron pair-productions and the astrophysical observations of compact stars with an electromagnetic structure.
Generation, characterization and use of atom-resonant indistinguishable photon pairs
Morgan W. Mitchell
2015-02-26T23:59:59.000Z
We describe the generation of atom-resonant indistinguishable photon pairs using nonlinear optical techniques, their spectral purification using atomic filters, characterization using multi-photon interference, and application to quantum-enhanced sensing with atoms. Using either type-I or type-II cavity-enhanced spontaneous parametric down-conversion, we generate pairs of photons in the resonant modes of optical cavities with linewidths comparable to the 6 MHz natural linewidth of the D$_1$ line of atomic rubidium. The cavities and pump lasers are tuned so that emission occurs in a mode or a pair of orthogonally-polarized modes that are resonant to the D$_1$ line, at 794.7 nm. The emission from these frequency-degenerate modes is separated from other cavity emission using ultra-narrow atomic frequency filters, either a Faraday anomalous dispersion optical filter (FADOF) with a 445MHz linewidth and 57 dB of out-of-band rejection or an induced dichroism filter with an 80 MHz linewidth and $\\ge$35dB out-of-band rejection. Using the type-I source, we demonstrate interference of photon pair amplitudes against a coherent state and a new method for full characterization of the temporal wave-function of narrow-band photon pairs. With the type-II source we demonstrate high-visibility super-resolving interference, a high-fidelity atom-tuned NooN state, and quantum enhanced sensing of atoms using indistinguishable photon pairs.
P. A. Marchetti; F. Ye; Z. B. Su; L. Yu
2011-05-25T23:59:59.000Z
Within a gauge approach to the t-J model, we propose a new, non-BCS mechanism of superconductivity for underdoped cuprates. We implement the no-double occupancy constraint with a (semionic) slave-particle formalism. The dopant generates a vortex-like quantum distortion of the AF background centered on the empty sites, with opposite chirality for cores on the two N\\'eel sublattices. Empty sites are described in terms of spinless fermionic holons and the long-range attraction between spin vortices on two opposite N\\'eel sublattices is the holon pairing force, leading eventually to SC. The spin fluctuations are described by bosonic spinons with a gap generated by scattering on spin vortices. Due to the occupation constraint, there is a gauge attraction between holon and spinon, binding them into a physical hole. Through gauge interaction the spin vortex attraction induces the formation of spin-singlet RVB pairs reducing the spinon gap. Lowering T, there are two crossovers as precursors of the SC transition: at the higher one a gas of holon pairs appears, reducing the hole spectral weight, while at the lower one a gas of spinon pairs also appears, giving rise to a gas of incoherent preformed hole pairs with magnetic vortices in the plasma phase, supporting a Nernst signal. At an even lower T the hole pairs become coherent and SC appears beyond a critical doping. The proposed SC mechanism is not of the BCS-type, because it involves a gain in kinetic energy (lowering of spinon gap) and it is "almost" of the classical 3D XY-type. Since both the spinon gap and the holon pairing originate from the same term in the slave-particle representation of the t-J model, this approach incorporates a strong interplay between AF and SC, giving rise to a universal relation between Tc and the energy of the resonance mode, as observed in neutron scattering experiments.
Possible Effects of Pair Echoes on Gamma-Ray Burst Afterglow Emission
Kohta Murase; Bing Zhang; Keitaro Takahashi; Shigehiro Nagataki
2009-02-27T23:59:59.000Z
High-energy emission from gamma-ray bursts (GRBs) is widely expected but had been sparsely observed until recently when the Fermi satellite was launched. If >TeV gamma rays are produced in GRBs and can escape from the emission region, they are attenuated by the cosmic infrared background photons, leading to regeneration of GeV-TeV secondary photons via inverse-Compton scattering. This secondary emission can last for a longer time than the duration of GRBs, and it is called a pair echo. We investigate how this pair echo emission affects spectra and light curves of high energy afterglows, considering not only prompt emission but also afterglow as the primary emission. Detection of pair echoes is possible as long as the intergalactic magnetic field (IGMF) in voids is weak. We find (1) that the pair echo from the primary afterglow emission can affect the observed high-energy emission in the afterglow phase after the jet break, and (2) that the pair echo from the primary prompt emission can also be relevant, but only when significant energy is emitted in the TeV range, typically E_{gamma, >0.1 TeV} > (Y/(1+Y)) epsilon_e E_k. Even non-detections of the pair echoes could place interesting constraints on the strength of IGMF. The more favorable targets to detect pair echoes may be the "naked" GRBs without conventional afterglow emission, although energetic naked GRBs would be rare. If the IGMF is weak enough, it is predicted that the GeV emission extends to >30-300 s.
Interesting features of nonlinear shock equations in dissipative pair-ion-electron plasmas
Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Rizvi, H. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan)
2011-09-15T23:59:59.000Z
Two dimensional nonlinear electrostatic waves are studied in unmagnetized, dissipative pair-ion-electron plasmas in the presence of weak transverse perturbation. The dissipation in the system is taken into account by incorporating the kinematic viscosity of both positive and negative ions. In the linear case, a biquadratic dispersion relation is obtained, which yields the fast and slow modes in a pair-ion-electron plasma. It is shown that the limiting cases of electron-ion and pair-ion can be retrieved from the general biquadratic dispersion relation, and the differences in the characters of the waves propagating in both the cases are also highlighted. Using the small amplitude approximation method, the nonlinear Kadomtsev Petviashvili Burgers as well as Burgers-Kadomtsev Petviashvili equations are derived and their applicability for pair-ion-electron plasma is explained in detail. The present study may have relevance to understand the formation of two dimensional electrostatic shocks in laboratory produced pair-ion-electron plasmas.
The Radical Pair Mechanism and the Avian Chemical Compass: Quantum Coherence and Entanglement
Yiteng Zhang; Gennady P. Berman; Sabre Kais
2015-03-23T23:59:59.000Z
We review the spin radical pair mechanism which is a promising explanation of avian navigation. This mechanism is based on the dependence of product yields on (1) the hyperfine interaction involving electron spins and neighboring nuclear spins and (2) the intensity and orientation of the geomagnetic field. One surprising result is that even at ambient conditions quantum entanglement of electron spins can play an important role in avian magnetoreception. This review describes the general scheme of chemical reactions involving radical pairs generated from singlet and triplet precursors; the spin dynamics of the radical pairs; and the magnetic field dependence of product yields caused by the radical pair mechanism. The main part of the review includes a description of the chemical compass in birds. We review: the general properties of the avian compass; the basic scheme of the radical pair mechanism; the reaction kinetics in cryptochrome; quantum coherence and entanglement in the avian compass; and the effects of noise. We believe that the "quantum avian compass" can play an important role in avian navigation and can also provide the foundation for a new generation of sensitive and selective magnetic-sensing nano-devices.
Generation of potential/surface density pairs in flat disks Power law distributions
J. -M. Hure; D. Pelat; A. Pierens
2007-06-25T23:59:59.000Z
We report a simple method to generate potential/surface density pairs in flat axially symmetric finite size disks. Potential/surface density pairs consist of a ``homogeneous'' pair (a closed form expression) corresponding to a uniform disk, and a ``residual'' pair. This residual component is converted into an infinite series of integrals over the radial extent of the disk. For a certain class of surface density distributions (like power laws of the radius), this series is fully analytical. The extraction of the homogeneous pair is equivalent to a convergence acceleration technique, in a matematical sense. In the case of power law distributions, the convergence rate of the residual series is shown to be cubic inside the source. As a consequence, very accurate potential values are obtained by low order truncation of the series. At zero order, relative errors on potential values do not exceed a few percent typically, and scale with the order N of truncation as 1/N**3. This method is superior to the classical multipole expansion whose very slow convergence is often critical for most practical applications.
Comparison of Three Cre-LoxP Based Paired-End Library Construction Methods
Peng, Ze; Nath, Nandita; Tritt, Andrew; Liang, Shoudan; Han, James; Pennacchio, Len; Chen, Feng
2013-03-26T23:59:59.000Z
Paired-end library sequencing has been proven useful in scaffold construction during de novo whole genome shotgun assembly. The ability of generating mate pairs with > 8 Kb insert sizes is especially important for genomes containing long repeats. To make mate paired libraries for next generation sequencing, DNA fragments need to be circularized to bring the ends together. There are several methods that can be used for DNA circulation, namely ligation, hybridization and Cre-LoxP recombination. With higher circularization efficiency with large insert DNA fragments, Cre-LoxP recombination method generally has been used for constructing >8 kb insert size paired-end libraries. Second fragmentation step is also crucial for maintaining high library complexity and uniform genome coverage. Here we will describe the following three fragmentation methods: restriction enzyme digestion, random shearing and nick translation. We will present the comparison results for these three methods. Our data showed that all three methods are able to generate paired-end libraries with greater than 20 kb insert. Advantages and disadvantages of these three methods will be discussed as well.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T.; Albin, E.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; et al
2013-07-01T23:59:59.000Z
We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at ?s=1.96 TeV corresponding to an integrated luminosity of 6.6 fb?. We find the data to be consistent with nonresonant production. We report limits on ?(pp??jjjj) as a function of the masses of themorehypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T.; Albin, E.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Ciocci, M. A.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; dAscenzo, N.; Datta, M.; De Barbaro, P.; Demortier, L.; Deninno, M.; Devoto, F.; dErrico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; DOnofrio, M.; Donati, S.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Eusebi, R.; Farrington, S.; Fernndez Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzlez Lpez, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kim, Y. J.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, P.; Martnez, M.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernndez, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Sorin, V.; Song, H.; Stancari, M.; Denis, R. St.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.
2013-07-01T23:59:59.000Z
We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at ?s=1.96 TeV corresponding to an integrated luminosity of 6.6 fb?. We find the data to be consistent with nonresonant production. We report limits on ?(pp??jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.
Search for pair-produced resonances decaying to jet pairs in proton-proton collisions at ?s = 8 TeV
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan
2015-07-01T23:59:59.000Z
Results are reported of a general search for pair production of heavy resonances decaying to pairs of jets in events with at least four jets. The study is based on up to 19.4 inverse femtobarns of integrated luminosity from proton-proton collisions at a center-of-mass energy of 8 TeV, recorded with the CMS detector at the LHC. Limits are determined on the production of scalar top quarks (top squarks) in the framework of R-parity violating supersymmetry and on the production of color-octet vector bosons (colorons). First limits at the LHC are placed on top squark production for two scenarios. The firstmoreassumes decay to a bottom quark and a light-flavor quark and is excluded for masses between 200 and 385 GeV, and the second assumes decay to a pair of light-flavor quarks and is excluded for masses between 200 and 350 GeV at 95% confidence level. Previous limits on colorons decaying to light-flavor quarks are extended to exclude masses from 200 to 835 GeV.less
Long-range Cooper pair splitter with high entanglement production rate
Wei Chen; D. N. Shi; D. Y. Xing
2015-01-05T23:59:59.000Z
Cooper pairs in the superconductor are a natural source of spin entanglement. The existing proposals of the Cooper pair splitter can only realize a low efficiency of entanglement production, and its size is constrained by the superconducting coherence length. Here we show that a long-range Cooper pair splitter can be implemented in a normal metal-superconductor-normal metal (NSN) junction by driving a supercurrent in the S. The supercurrent results in a band gap modification of the S, which significantly enhances the crossed Andreev reflection (CAR) of the NSN junction and simultaneously quenches its elastic cotunneling. Therefore, a high entanglement production rate close to its saturation value can be achieved by the inverse CAR. Interestingly, in addition to the conventional entangled electron states between opposite energy levels, novel entangled states with equal energy can also be induced in our proposal.
Statistics of simulated and observed pair separations in the Gulf of Mexico
Beron-Vera, F J
2015-01-01T23:59:59.000Z
Pair-separation statistics of in-situ and synthetic surface drifters deployed near the \\emph{Deepwater Horizon} site in the Gulf of Mexico are investigated. The synthetic trajectories derive from synthetic particles advected by surface velocities from a 1-km-resolution data-assimilative Navy Coastal Ocean Model (NCOM) simulation. The in-situ drifters were launched in the Grand LAgrangian Deployment (GLAD). The statistical measures are of two classes---those which are functions of time, including the probability distribution function (PDF) of pair separations, the relative dispersion and the kurtosis, and those which are functions of separation, including the second-order velocity structure function and the relative diffusivity. The measures yield a consistent picture of the dispersion with the simulated pairs, with nonlocal dispersion from separations of 1 km to the Rossby deformation radius, $L_\\mathrm{D}$, and diffusive dispersion above $L_\\mathrm{D}$. The measures are less consistent with the GLAD drifters...
Study of correlation of PDF uncertainty in single top and top pair production at the LHC
The ATLAS collaboration
2015-01-01T23:59:59.000Z
The incomplete knowledge of parton distribution functions is an important source of systematic uncertainty for top-quark measurements, including top-quark pair and single top-quark production cross sections, as well as for analyses that have a large background from these processes. The correlation of the parton-distribution-function uncertainty is studied for top-quark pair production and single top-quark production in association with a W boson, in final states with two reconstructed leptons. Four types of correlation are studied: between total production cross-sections, between cross-section and acceptance correction, between the two processes for common selection requirements, and between different jet multiplicity requirements. The uncertainty correlation is evaluated for several sets of parton distribution functions using simulated samples of top-quark pair and single top-quark events.
Index pairings in presence of symmetries with applications to topological insulators
Julian Grossmann; Hermann Schulz-Baldes
2015-04-07T23:59:59.000Z
In a basic framework of a complex Hilbert space furnished with a complex conjugation and an involution, linear operators can be real, quaternionic, symmetric or anti-symmetric, and orthogonal projections can furthermore be symplectic. This paper investigates index pairings of projections and unitaries submitted to such symmetries. Various scenarios emerge: Noether indices can take either arbitrary integer values or only even integer values or they can vanish and then possibly have secondary $\\mathbb{Z}_2$-invariants. These general results are applied to prove index theorems for the strong invariants of topological insulators. The symmetries come from the Fermi projection ($K$-theoretic part of the pairing) and the Dirac operator ($K$-homological part of the pairing depending on the dimension of physical space).
Z. L. Li; D. Lu; B. F. Shen; L. B. Fu; J. Liu; B. S. Xie
2014-10-23T23:59:59.000Z
The mass shift effects in multiphoton pair production of a nonperturbative nature for arbitrary polarized electric fields are investigated numerically by employing the real-time Dirac-Heisenberg-Wigner formalism, and theoretically by proposing an effective energy concept. It is found that the theoretical results are agreement with the numerical ones very well. It is the first time to consider the roles of the momenta of created particles and the polarizations of external fields played in the mass shift effects. These results can deepen the understanding of pair production in the nonperturbative threshold regime. Moreover, the distinct mass shift effects are observable in the forthcoming experiments and can be used as a probe to distinguish the electron-positron pair production from other background events.
Krawtchouk polynomials, the Lie algebra $\\mathfrak{sl}_2$, and Leonard pairs
Nomura, Kazumasa
2012-01-01T23:59:59.000Z
A Leonard pair is a pair of diagonalizable linear transformations of a finite-dimensional vector space, each of which acts in an irreducible tridiagonal fashion on an eigenbasis for the other one. In the present paper we give an elementary but comprehensive account of how the following are related: (i) Krawtchouk polynomials; (ii) finite-dimensional irreducible modules for the Lie algebra ${\\mathfrak{sl}_2}$; (iii) a class of Leonard pairs said to have Krawtchouk type. Along the way we obtain elementary proofs of some well-known facts about Krawtchouk polynomials, such as the three-term recurrence, the orthogonality, the difference equation, and the generating function. The paper is a tutorial meant for a graduate student or a researcher unfamiliar with the above topics.
The vacuum bubbles in de Sitter background and black hole pair creation
Bum-Hoon Lee; Wonwoo Lee
2009-10-07T23:59:59.000Z
We study the possible types of the nucleation of vacuum bubbles. We classify vacuum bubbles in de Sitter background and present some numerical solutions. The thin-wall approximation is employed to obtain the nucleation rate and the radius of vacuum bubbles. With careful analysis we confirm that Parke's formula is also applicable to the large true vacuum bubbles. The nucleation of the false vacuum bubble in de Sitter background is also evaluated. The tunneling process in the potential with degenerate vacua is analyzed as the limiting cases of the large true vacuum bubble and false vacuum bubble. Next, we consider the pair creation of black holes in the background of bubble solutions. We obtain static bubble wall solutions of junction equation with black hole pair. The masses of created black holes are uniquely determined by the cosmological constant and surface tension on the wall. Finally, we obtain the rate of pair creation of black holes.
Neutral Higgs boson pair production at the linear collider in the noncommutative standard model
Das, Prasanta Kumar; Prakash, Abhishodh; Mitra, Anupam [Birla Institute of Technology and Science-Pilani, K.K. Birla Goa Campus, NH-17B, Zuarinagar, Goa-403726 (India)
2011-03-01T23:59:59.000Z
We study the Higgs boson pair production at the linear collider in the noncommutative extension of the standard model using the Seiberg-Witten map of this to the first order of the noncommutative parameter {Theta}{sub {mu}{nu}}. Unlike the standard model (where the process is forbidden) here the Higgs boson pair directly interacts with the photon. We find that the pair production cross section can be quite significant for the noncommutative scale {Lambda} lying in the range 0.5 TeV to 1.0 TeV. Using the experimental (LEP 2, Tevatron, and global electroweak fit) bound on the Higgs mass, we obtain 626 GeV{<=}{Lambda}{<=}974 GeV.
HIV-1 sequence variation between isolates from mother-infant transmission pairs
Wike, C.M.; Daniels, M.R.; Furtado, M.; Wolinsky, M.; Korber, B.; Hutto, C.; Munoz, J.; Parks, W.; Saah, A.
1991-12-31T23:59:59.000Z
To examine the sequence diversity of human immunodeficiency virus type 1 (HIV-1) between known transmission sets, sequences from the V3 and V4-V5 region of the env gene from 4 mother-infant pairs were analyzed. The mean interpatient sequence variation between isolates from linked mother-infant pairs was comparable to the sequence diversity found between isolates from other close contacts. The mean intrapatient variation was significantly less in the infants` isolates then the isolates from both their mothers and other characterized intrapatient sequence sets. In addition, a distinct and characteristic difference in the glycosylation pattern preceding the V3 loop was found between each linked transmission pair. These findings indicate that selection of specific genotypic variants, which may play a role in some direct transmission sets, and the duration of infection are important factors in the degree of diversity seen between the sequence sets.
HIV-1 sequence variation between isolates from mother-infant transmission pairs
Wike, C.M.; Daniels, M.R.; Furtado, M.; Wolinsky, M.; Korber, B.; Hutto, C.; Munoz, J.; Parks, W.; Saah, A.
1991-01-01T23:59:59.000Z
To examine the sequence diversity of human immunodeficiency virus type 1 (HIV-1) between known transmission sets, sequences from the V3 and V4-V5 region of the env gene from 4 mother-infant pairs were analyzed. The mean interpatient sequence variation between isolates from linked mother-infant pairs was comparable to the sequence diversity found between isolates from other close contacts. The mean intrapatient variation was significantly less in the infants' isolates then the isolates from both their mothers and other characterized intrapatient sequence sets. In addition, a distinct and characteristic difference in the glycosylation pattern preceding the V3 loop was found between each linked transmission pair. These findings indicate that selection of specific genotypic variants, which may play a role in some direct transmission sets, and the duration of infection are important factors in the degree of diversity seen between the sequence sets.
A CLOSE-PAIR ANALYSIS OF DAMP MERGERS AT INTERMEDIATE REDSHIFTS
Chou, Richard C. Y.; Abraham, Roberto G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Bridge, Carrie R., E-mail: chou@astro.utoronto.ca, E-mail: abraham@astro.utoronto.ca, E-mail: bridge@astro.caltech.edu [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
2012-12-01T23:59:59.000Z
We have studied the kinematics of {approx}2800 candidate close-pair galaxies at 0.1 < z < 1.2 identified from the Canada-France-Hawaii Telescope Legacy Survey fields. Spectra of these systems were obtained using spectrometers on the 6.5 m Magellan and 5 m Hale telescopes. These data allow us to constrain the rate of dry mergers at intermediate redshifts and to test the 'hot halo' model for quenching of star formation. Using virial radii estimated from the correlation between dynamical and stellar masses published by Leauthaud et al., we find that around 1/5 of our candidate pairs are likely to share a common dark matter halo (our metric for close physical association). These pairs are divided into red-red, blue-red, and blue-blue systems using the rest-frame colors classification method introduced in Chou et al.. Galaxies classified as red in our sample have very low star formation rates, but they need not be totally quiescent, and hence we refer to them as 'damp', rather than 'dry', systems. After correcting for known selection effects, the fraction of blue-blue pairs is significantly greater than that of red-red and blue-red pairs. Red-red pairs are almost entirely absent from our sample, suggesting that damp mergers are rare at z {approx} 0.5. Our data support models with a short merging timescale (<0.5 Gyr) in which star formation is enhanced in the early phase of mergers, but quenched in the late phase. Hot halo models may explain this behavior, but only if virial shocks that heat gas are inefficient until major mergers are nearly complete.
Nuclear pairing from bare interaction: Two and three-body chiral forces
Finelli, Paolo [Physics Department, University of Bologna, Via Irnerio 46, 40126 Bologna (Italy); INFN, Section of Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy)
2012-10-20T23:59:59.000Z
In a recent paper the {sup 1}S{sub 0} pairing gap in isospin-symmetric nuclear matter and finite nuclei has been investigated starting from the chiral nucleon-nucleon potential at the N{sup 3}LO order in the two-body sector and the N{sup 2}LO order in the three-body sector. To include realistic nuclear forces in RHB (Relativistic Hartree Bolgoliubov) calculations we relied on a separable representation of the pairing interaction. In this paper we would like to show recent results concerning isotonic chains with N= 28,50,82.
Feedback effects on the pairing interaction in color superconductors near the transition temperature
Kei Iida
2005-07-13T23:59:59.000Z
We examine the role that the gap dependence of the pairing interaction plays in the gap equation for a weakly coupled uniform superfluid of three-flavor massless quarks near the transition temperature T_c. We find that the feedback effects on Landau-damped transverse gluons mediating the pairing interaction alter the gap magnitude in a way dependent on the color structure of the gap. We estimate corrections by these effects to the parameters characterizing the fourth order terms in the Ginzburg-Landau free energy and ensure the stability of a color-flavor locked state near T_c.
On the frequency of oscillations in the pair plasma generated by a strong electric field
A. Benedetti; W. -B. Han; R. Ruffini; G. V. Vereshchagin
2011-02-21T23:59:59.000Z
We study the frequency of the plasma oscillations of electron-positron pairs created by the vacuum polarization in an uniform electric field with strength E in the range 0.2 Ec plasma oscillation equation when E -> 0. Thereby, we focus our attention on its evolution in time studying how this oscillation frequency approaches the plasma frequency. The time-scale needed to approach to the plasma frequency and the power spectrum of these oscillations are computed. The characteristic frequency of the power spectrum is determined uniquely from the initial value of the electric field strength. The effects of plasma degeneracy and pair annihilation are discussed.
Discovering Higgs boson pair production through rare final states at a 100 TeV collider
Papaefstathiou, Andreas
2015-01-01T23:59:59.000Z
We consider Higgs boson pair production at a future proton collider with centre-of-mass energy of 100 TeV, focusing on rare final states that include a bottom-anti-bottom quark pair and multiple isolated leptons: $hh \\rightarrow (b\\bar{b}) + n \\ell + X$, $n = \\{2,4\\}$, $X = \\{ E_T^\\mathrm{miss}, \\gamma, -\\}$. We construct experimental search strategies for observing the process through these channels and make suggestions on the desired requirements for the detector design of the future collider.
Validity of pair truncation of the nuclear shell model in {sup 46}Ca
Lei, Y.; Xu, Z. Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); CCAST, World Laboratory, Post Office Box 8730, Beijing 100080 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda-ku, Tokyo 102-0091 (Japan)
2009-12-15T23:59:59.000Z
We study the validity of pair truncation of the nuclear shell model by using the semimagic nucleus {sup 46}Ca. We present low-lying states and their E2 transition rates based on both nucleon pair approximation (NPA) and exact shell-model (SM) calculations. We also calculate overlaps between wave functions of low-lying states calculated by using the NPA and those calculated by using the SM. Our calculated results show a remarkable agreement between the NPA results and the SM results, although the NPA is a drastic truncation of the SM.
Gap anisotropy and universal pairing scale in a spin-fluctuation model of cuprate superconductors
Abanov, Artem; Chubukov, A. V.; Norman, M. R.
2008-01-01T23:59:59.000Z
-Tc cu- prate superconductors is a key problem.1 Some argue that the pseudogap originates from #1;quasi-#2;long-range order in a non- pairing channel #1;two-gap scenario#2;.2 Others argue instead that the pseudogap is a phase in which fermions already... and W is the bandwidth. For u#2;1, it is natural to assume that pairing is confined to near the Fermi surface and can be thought of as mediated by a bosonic ?glue,? the most natural candidate being collective excitations in the spin channel, enhanced...
Reduced effect of impurities on the universal pairing scale in the cuprates
Vorontsov, A. B.; Abanov, Artem; Vavilov, M. G.; Chubukov, A. V.
2010-01-01T23:59:59.000Z
corrections are small numerically.22 The set of equations includes fermionic and bosonic self- energies in the normal state and the linearized equation for the d-wave pairing vertex #11;pf #12; #1; m#2; #1;Ref. 1#2; pf#1; m#2; = #5;T #1;#7; m#1; #8...; /2#5;T #1;#2;?#7;#1;1 /2#2;, where #7;#1;x#2; is the di-Gamma function and T 0 #1; is the pairing temperature in the absence of impurities #1;for an s-wave and magnetic impurities, the formula is the same,7 but with #3; /2 instead of #3...
Neutrinoless Double Beta Decay within QRPA with Proton-Neutron Pairing
G. Pantis; F. Simkovic; J. D. Vergados; Amand Faessler
1996-12-14T23:59:59.000Z
We have investigated the role of proton-neutron pairing in the context of the Quasiparticle Random Phase approximation formalism. This way the neutrinoless double beta decay matrix elements of the experimentally interesting A= 48, 76, 82, 96, 100, 116, 128, 130 and 136 systems have been calculated. We have found that the inclusion of proton-neutron pairing influences the neutrinoless double beta decay rates significantly, in all cases allowing for larger values of the expectation value of light neutrino masses. Using the best presently available experimental limits on the half life-time of neutrinoless double beta decay we have extracted the limits on lepton number violating parameters.
Shape and pairing fluctuations effects on neutrinoless double beta decay nuclear matrix elements
Nuria Lpez Vaquero; Toms R. Rodrguez; J. Luis Egido
2014-01-03T23:59:59.000Z
Nuclear matrix elements (NME) for the most promising candidates to detect neutrinoless double beta decay have been computed with energy density functional methods including deformation and pairing fluctuations explicitly on the same footing. The method preserves particle number and angular momentum symmetries and can be applied to any decay without additional fine tunings. The finite range density dependent Gogny force is used in the calculations. An increase of $10\\%-40\\%$ in the NME with respect to the ones found without the inclusion of pairing fluctuations is obtained, reducing the predicted half-lives of these isotopes.
Gap anisotropy and universal pairing scale in a spin-fluctuation model of cuprate superconductors
Abanov, Artem; Chubukov, A. V.; Norman, M. R.
2008-01-01T23:59:59.000Z
Gap anisotropy and universal pairing scale in a spin-fluctuation model of cuprate superconductors Ar. Abanov,1 A. V. Chubukov,2 and M. R. Norman3 1Department of Physics, Texas A&M University, College Station, Texas 77843, USA 2Department...-Tc cu- prate superconductors is a key problem.1 Some argue that the pseudogap originates from #1;quasi-#2;long-range order in a non- pairing channel #1;two-gap scenario#2;.2 Others argue instead that the pseudogap is a phase in which fermions already...
A Method for Constructing a Lax Pair for the Ernst Equation
C. J. Papachristou; B. Kent Harrison
2009-10-26T23:59:59.000Z
A systematic construction of a Lax pair and an infinite set of conservation laws for the Ernst equation is described. The matrix form of this equation is rewritten as a differential ideal of gl(2,R)-valued differential forms, and its symmetry condition is expressed as an exterior equation which is linear in the symmetry characteristic and has the form of a conservation law. By means of a recursive process, an infinite collection of such laws is then obtained, and the conserved "charges" are used to derive a linear exterior equation whose components constitute a Lax pair.
Energy levels of odd-even nuclei using broken pair model
Hamammu, I. M.; Haq, S.; Eldahomi, J. M. [Department of Physics, Faculty of Science Benghazi University, P. O. Box 9480 Benghazi (Libya)
2012-09-06T23:59:59.000Z
A method to calculate energy levels and wave functions of odd-even nuclei, in the frame work of the broken pair model have been developed. The accuracy of the model has been tested by comparing the shell model results of limiting cases in which the broken pair model exactly coincides with the shell model, where there are two-proton/neutron + one-neutron/proton in the valence levels. The model is then applied to calculate the energy levels of some nuclei in the Zirconium region. The model results compare reasonably well with the shell model as well as with the experimental data.
Production of mixed flavour heavy quarkonium pair $\\Upsilon(1S) J/\\psi$ at LHC
Likhoded, A K; Poslavsky, S V
2015-01-01T23:59:59.000Z
Inclusive production of $\\Upsilon J/\\psi$ pair in proton-proton interation at LHCb is considered. This process is forbidden at leading order of perturbation theory, so such channels as double parton scattering, $\\chi_b\\chi_c$ pair production with subsequent radiative decays of $P$-wave quarkonia, contributions of color-octet states, and NLO corrections are studied in details. For all these channels we present theoretical predictions of total cross sections at LHCb and distributions over different kinematical variables. According to presented in the paper results, double parton interaction gives main contribution to the cross section of the considered reaction.
Subnatural-Linewidth Polarization-Entangled Photon Pairs with Controllable Temporal Length
Kaiyu Liao; Hui Yan; Junyu He; Shengwang Du; Zhi-Ming Zhang; Shi-Liang Zhu
2014-07-15T23:59:59.000Z
We demonstrate an efficient experimental scheme for producing polarization-entangled photon pairs from spontaneous four-wave mixing (SFWM) in a laser-cooled $^{85}$Rb atomic ensemble, with a bandwidth (as low as 0.8 MHz) much narrower than the rubidium atomic natural linewidth. By stabilizing the relative phase between the two SFWM paths in a Mach-Zehnder interferometer configuration, we are able to produce all four Bell states. These subnatural-linewidth photon pairs with polarization entanglement are ideal quantum information carriers for connecting remote atomic quantum nodes via efficient light-matter interaction in a photon-atom quantum network.
Spin polarized electron-positron pair production via elliptical polarized laser fields
Wllert, Anton; Keitel, Christoph H
2015-01-01T23:59:59.000Z
We study nonperturbative multiphoton electron-positron pair creation in ultra-strong electromagnetic fields formed by two counterpropagating pulses with elliptic polarization. Our numerical approach allows us to take into account the temporal as well as the spatial variation of the standing electromagnetic field. The spin and momentum resolved pair creation probabilities feature characteristic Rabi oscillations and resonance spectra. Therefore, each laser frequency features a specific momentum distribution of the created particles. We find that depending on the relative polarization of both pulses the created electrons may be spin polarized along the direction of field propagation.
Reduced effect of impurities on the universal pairing scale in the cuprates
Vorontsov, A. B.; Abanov, Artem; Vavilov, M. G.; Chubukov, A. V.
2010-01-01T23:59:59.000Z
corrections are small numerically.22 The set of equations includes fermionic and bosonic self- energies in the normal state and the linearized equation for the d-wave pairing vertex #11;pf #12; #1; m#2; #1;Ref. 1#2; pf#1; m#2; = #5;T #1;#7; m#1; #8...; /2#5;T #1;#2;?#7;#1;1 /2#2;, where #7;#1;x#2; is the di-Gamma function and T 0 #1; is the pairing temperature in the absence of impurities #1;for an s-wave and magnetic impurities, the formula is the same,7 but with #3; /2 instead of #3...
Equal-spin pairing state of superfluid {sup 3}He in aerogel
Aoyama, Kazushi; Ikeda, Ryusuke [Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)
2005-07-01T23:59:59.000Z
The equal-spin pairing state, the so-called A-like phase, of superfluid {sup 3}He in aerogels is studied theoretically in the Ginzburg-Landau region by examining thermodynamics, and the resulting equilibrium phase diagram is mapped out. We find that the ABM pairing state with presumably quasi-long-ranged superfluid order has a lower free energy than the planar and 'robust' states and is the best candidate of the A-like phase with a strange lowering of the polycritical point observed experimentally.
Spin polarized electron-positron pair production via elliptical polarized laser fields
Anton Wllert; Heiko Bauke; Christoph H. Keitel
2015-02-23T23:59:59.000Z
We study nonperturbative multiphoton electron-positron pair creation in ultra-strong electromagnetic fields formed by two counterpropagating pulses with elliptic polarization. Our numerical approach allows us to take into account the temporal as well as the spatial variation of the standing electromagnetic field. The spin and momentum resolved pair creation probabilities feature characteristic Rabi oscillations and resonance spectra. Therefore, each laser frequency features a specific momentum distribution of the created particles. We find that depending on the relative polarization of both pulses the created electrons may be spin polarized along the direction of field propagation.
Recent results from HADES on electron pair production in relativistic heavy-ion collisions
The HADES Collaboration; T. Galatyuk; G. Agakishiev; A. Balanda; D. Belver; A. V. Belyaev; A. Blanco; M. Bhmer; J. L. Boyard; P. Braun-Munzinger; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Daz; F. Dohrmann; A. Dybczak; L. Fabbietti; O. V. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Frhlich; J. A. Garzn; R. Gernhuser; A. Gil; C. Gilardi; M. Golubeva; D. Gonzlez-Daz; F. Guber; T. Hennino; R. Holzmann; I. Iori; A. Ivashkin; M. Jurkovic; B. Kmpfer; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; F. Krizek; R. Krcken; W. Khn; A. Kugler; A. Kurepin; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Markert; V. Metag; B. Michalska; J. Michel; E. Morinire; J. Mousa; C. Mntz; L. Naumann; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; A. Rustamov; A. Sadovsky; P. Salabura; A. Schmah; E. Schwab; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Strbele; J. Stroth; C. Sturm; M. Sudol; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; V. Wagner; M. Weber; M. Wisniowski; T. Wojcik; J. Wstenfeld; S. Yurevich; Y. V. Zanevsky; P. Zhou
2009-11-12T23:59:59.000Z
Systematic investigations of dilepton production are performed at the SIS accelerator of GSI with the HADES spectrometer. The goal of this program is a detailed understanding of di-electron emission from hadronic systems at moderate temperatures and densities. New results obtained in HADES experiments focussing on electron pair production in elementary collisions are reported here. They pave the way to a better understanding of the origin of the so-called excess pairs earlier on observed in heavy-ion collisions by the DLS collaboration and lately confirmed in two measurements of the HADES collaboration using C+C and Ar+KCl collisions. Results of these studies are discussed.
Study of correlations between photoproduced pairs of charmed particles at Experiment E831/FOCUS
Castromonte Flores, Cesar Manuel; /Rio de Janeiro, CBPF
2008-08-01T23:59:59.000Z
The authors present the study of the charm-pair correlations produced in photon-nucleon interactions at
Compositions of orthogonal lysyl-tRNA and aminoacyl-tRNA synthetase pairs and uses thereof
Anderson, J. Christopher (San Francisco, CA); Wu, Ning (Brookline, MA); Santoro, Stephen (Cambridge, MA); Schultz, Peter G. (La Jolla, CA)
2009-12-29T23:59:59.000Z
Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal lysyl-tRNAs, orthogonal lysyl-aminoacyl-tRNA synthetases, and orthogonal pairs of lysyl-tRNAs/synthetases, which incorporate homoglutamines into proteins are provided in response to a four base codon. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with homoglutamines using these orthogonal pairs.
Compositions of orthogonal lysyl-tRNA and aminoacyl-tRNA synthetase pairs and uses thereof
Anderson, J. Christopher (San Francisco, CA); Wu, Ning (Brookline, MA); Santoro, Stephen (Cambridge, MA); Schultz, Peter G. (La Jolla, CA)
2011-10-04T23:59:59.000Z
Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal lysyl-tRNAs, orthogonal lysyl-aminoacyl-tRNA synthetases, and orthogonal pairs of lysyl-tRNAs/synthetases, which incorporate homoglutamines into proteins are provided in response to a four base codon. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with homoglutamines using these orthogonal pairs.
Compositions of orthogonal lysyl-tRNA and aminoacyl-tRNA synthetase pairs and uses thereof
Anderson, J. Christopher (San Francisco, CA); Wu, Ning (Brookline, MA); Santoro, Stephen (Cambridge, MA); Schultz, Peter G. (La Jolla, CA)
2009-08-18T23:59:59.000Z
Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal lysyl-tRNAs, orthogonal lysyl-aminoacyl-tRNA synthetases, and orthogonal pairs of lysyl-tRNAs/synthetases, which incorporate homoglutamines into proteins are provided in response to a four base codon. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with homoglutamines using these orthogonal pairs.
Compositions of orthogonal lysyl-tRNA and aminoacyl-tRNA synthetase pairs and uses thereof
Anderson, J. Christopher; Wu, Ning; Santoro, Stephen; Schultz, Peter G
2014-03-11T23:59:59.000Z
Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal lysyl-tRNAs, orthogonal lysyl-aminoacyl-tRNA synthetases, and orthogonal pairs of lysyl-tRNAs/synthetases, which incorporate homoglutamines into proteins are provided in response to a four base codon. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with homoglutamines using these orthogonal pairs.
Using a Bayesian Network in the ProdFLOWTM Stefan Wagner
unchen Garching b. Munchen, Germany wagnerst@in.tum.de Melanie Ruhe Siemens AG Munich, Germany melanie.ruhe@siemens- ment organisations created by the research department of the Siemens AG. Its core are organisation to be adapted to the characteristics of R&D. In the research department of the Siemens AG a new approach
PROD. TYPE: COM PP:1-17 (col.fig.: nil) CBM856 MODE+
Serpen, Gursel
). The main premise is that there exists substantial and significant specialized knowledge in the domain of PE reserved. doi:10.1016/j.compbiomed.2007.10.001 ventilationperfusion scans along with correlated chest X
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Nabben, Reinhard
- croscope images revealed 109 QDs=cm2 with a11 at, truncated shape. Di erent pieces of the sam- ple were properties. The investigated sam- ples were derived from a single sample by ex5 situ annealing as described
Department: Theatre and Film 2013/14 Season Prod. # Feb 24, 2014 Ver. 8
Martin, Jeff
Game by Eugene Ionesco, trans Helen Gary Bishop Event Date & Time: Tue, Nov 26 - Fri, Nov 29 - 8pm, Sat Churchill Event Date & Time: Sat Mar 29 Director: Blake Taylor Location: ACTF Theatre 1T15, Possession: Fri
int. j. prod. res., 2001, vol. 39, no. 16, 35613600 A review of agile manufacturing systems
Nagi, Rakesh
literature on agile manufacturing. About 73 papers from premier scien- ti®c journals and conferences have Manufacturing International Journal of Production Research ISSN 0020±7543 print/ISSN 1366±588X online # 2001 Taylor & Francis Ltd http://www.tandf.co.uk/journals DOI: 10.1080/00207540110068790 Revision received
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Andras, Peter
statistically valid population decoding models3 Peter Andras, Stefano Panzeri, Malcolm P. Young Neural Systems to formalize the read-out model, Monte Carlo validation to check the statistical validity of the model. Andras), stefano.panzeri@ncl.ac.uk (S. Panzeri), m.p.young@ncl.ac.uk (M. P. Young). 0925-2312/02/$ - see
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Garver, John I.
-- SCAN: Padma ARTICLE IN PRESS Radiation Measurements ( ) www.elsevier.com/locate/radmeas 1 Etching tracks with a optical microscope using at a total magniÿcation between 1250? and 1600? ( 80%)9 with about to sample. This problem is undoubtedly due to sample-to-sample vari- 53 ation in -damage (combined -recoil
http://cemp.dri.edu/cgi-bin/cemp_stations.pl?stn=tono&prod=11
National Nuclear Security Administration (NNSA)
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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilAElectronic Input Options Gary L. Hirsch SNLMaythe InteriorWaterhepf3 Community
http://cemp.dri.edu/cgi-bin/cemp_stations.pl?stn=tono&prod=11
National Nuclear Security Administration (NNSA)
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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilAElectronic Input Options Gary L. Hirsch SNLMaythe InteriorWaterhepf3 Community1
NIR Luminosity Function of Galaxies in Close Major-Merger Pairs and Mass Dependence of Merger Rate
C. K. Xu; Y. C. Sun; X. T. He
2004-02-07T23:59:59.000Z
A sample of close major-merger pairs (projected separation ${\\rm 5 \\leq r \\leq 20 h^{-1}}$ kpc, ${\\rm K_s}$ band magnitude difference $\\delta {\\rm K_s} \\leq 1$ mag) is selected from the matched 2MASS-2dFGRS catalog of Cole et al. (2001). The pair primaries are brighter than ${\\rm K_s} = 12.5$ mag. After corrections for various biases, the comparison between counts in the paired galaxy sample and counts in the parent sample shows that for the local `M* galaxies' sampled by flux limited surveys, the fraction of galaxies in the close major-merger pairs is 1.70$\\pm 0.32%$. Using 38 paired galaxies in the sample, a ${\\rm K_s}$ band luminosity function (LF) is calculated. This is the first unbiased LF for a sample of objectively defined interacting/merging galaxies in the local universe, while all previously determined LFs of paired galaxies are biased by mistreating paired galaxies as singles. A stellar mass function (MF) is translated from the LF. Compared to the LF/MF of 2MASS galaxies, a differential pair fraction function is derived. The results suggest a trend in the sense that less massive galaxies may have lower chance to be involved in close major-merger pairs than more massive galaxies. The algorithm presented in this paper can be easily applied to much larger samples of 2MASS galaxies with redshifts in near future.
Drell-Yan Lepton pair production at NNLO QCD with parton showers
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hoeche, Stefan [SLAC National Accelerator Lab., Menlo Park, CA (United States); Li, Ye [SLAC National Accelerator Lab., Menlo Park, CA (United States); Prestel, Stefan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2015-04-01T23:59:59.000Z
We present a simple approach to combine NNLO QCD calculations and parton showers, based on the UNLOPS technique. We apply the method to the computation of Drell-Yan lepton-pair production at the Large Hadron Collider. We comment on possible improvements and intrinsic uncertainties.
JOINTLY HYPONORMAL PAIRS OF COMMUTING SUBNORMAL OPERATORS NEED NOT BE JOINTLY SUBNORMAL
Curto, Raúl
JOINTLY HYPONORMAL PAIRS OF COMMUTING SUBNORMAL OPERATORS NEED NOT BE JOINTLY SUBNORMAL RA´UL E operators, jointly hyponormal but not admitting commuting normal extensions. Each such family can be used] := ST - TS. We say that an n-tuple T = (T1, · · · , Tn) of operators on H is (jointly) hyponormal
29 Nov 2001 A. Bacchetta -Fragmentation to probe transversity 31 Hadron pair azimuthal angle
1 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 31 Hadron pair azimuthal angle 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 32 Center of mass angle hadron decay plane Center of mass direction in lab frame Center of mass frame R #12;2 29 Nov 2001 A. Bacchetta
Costa, Eunice
The layer-by-layer (LbL) assembly of polyelectrolyte pairs on temperature and pH-sensitive cross-linked poly(N-isopropylacrylamide)-co-(methacrylic acid), poly(NIPAAm-co-MAA), microgels enabled a fine-tuning of the gel ...
Pairs and heptamers of C70 molecules ordered via PTCDI-melamine supramolecular networks
Castell, Martin
Pairs and heptamers of C70 molecules ordered via PTCDI-melamine supramolecular networks Fabien Silly Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom and Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands Adam
Model Calculations of Protein Pair Interference Functions P. B. MOORE AND D. I~. ENGELMAN
of the interference cross term, derived from neutron scattering studies of structures containing pairs of deuterated by the neutron scattering method, and should help clarify the interpretation of such data. A2. Method Our and -~2 are the radii of the spheres in question, px and p2 are their respective scattering densities
Higher twist contributions to lepton-pair production and other QCD processes
Brodsky, S.J.; Berger, E.L.; Lepage, G.P.
1982-12-01T23:59:59.000Z
A general discussion of the calculations and phenomenological consequences of power-law suppressed QCD processes is given with emphasis on tests in massive lepton pair production. Absolutely normalized predictions are given for the leading twist (transverse current) and higher twist (longitudinal current) contributions to the meson structure function in the region of large x.
First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider
Paus, Christoph M. E.
We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W, Z) where one boson decays to a dijet final state. The data correspond to 3.5??fb[superscript -1] of ...
Peck, Mason A.
American Institute of Aeronautics and Astronautics 1 A Flux-Pinned Magnet-Superconductor Pair consisting of combinations of magnets and Type II superconductors, establishing a non-contacting interaction between the modules thanks to magnetic flux pinning. This stable action-at-a- distance interaction
Use of Exchangeable Pairs in the Analysis of Simulations Charles Stein with
labels (the so-called magnetization), direct or theoretical evaluation of EW is impossible e.g. when N are introduced. The relation with reversible Markov chains is recalled. A basic identity for an exchangeable pair (Stein [23]) and to derive combinatorial formulae for balls and boxes and cycle lengths in random
Nuclear Physics A 781 (2007) 317341 Symmetry energies, pairing energies, and mass
O'Donnell, Tom
2007-01-01T23:59:59.000Z
Nuclear Physics A 781 (2007) 317341 Symmetry energies, pairing energies, and mass equations J of the respective mass equation since symmetry energies are related to the curvature of the nuclear mass surface.10.Dr; 21.10.Hw; 21.30.Fe; 21.60.-n Keywords: NUCLEAR STRUCTURE Z = 1118; analyzed isobaric analog
A Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry
Gerstein, Mark
uncertainties in this data set closely match numerical values reported in the recent survey of nucleic acid baseA Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry These preliminary (Rockefeller University), Richard E. Dickerson (University of California, Los Angeles), Mark Gerstein (Yale
Domanski, Tadeusz
Influence of pair coherence on charge tunneling through a quantum dot connected the temperature below T* larger than Tc the single particle states become gradually depleted over a certain energy to a close neighborhood to the Mott insulating state, or because of competition with some other types
R. Rodriguez-Guzman; Y. Alhassid; G. F. Bertsch
2007-09-04T23:59:59.000Z
We describe a procedure for mapping a self-consistent mean-field theory (also known as density functional theory) into a shell model Hamiltonian that includes quadrupole-quadrupole and monopole pairing interactions in a truncated space. We test our method in the deformed N=Z sd-shell nuclei Ne-20, Mg-24 and Ar-36, starting from the Hartree-Fock plus BCS approximation of the USD shell model interaction. A similar procedure is then followed using the SLy4 Skyrme energy density functional in the particle-hole channel plus a zero-range density-dependent force in the pairing channel. Using the ground-state solution of this density functional theory at the Hartree-Fock plus BCS level, an effective shell model Hamiltonian is constructed. We use this mapped Hamiltonian to extract quadrupolar and pairing correlation energies beyond the mean field approximation. The rescaling of the mass quadrupole operator in the truncated shell model space is found to be almost independent of the coupling strength used in the pairing channel of the underlying mean-field theory.
D0 Collaboration; V. Abazov
2011-07-10T23:59:59.000Z
We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron Collider in ppbar collisions at $\\sqrt{s}=1.96$ TeV. In the channel $LQ \\bar{LQ} \\rightarrow e\
Stillinger, Frank
Synthetic diamond and wurtzite structures self-assemble with isotropic pair interactions Mikael C with strongly repulsive cores that cause the tetrahedrally coordinated diamond and wurtzite lattices-dimensional diamond and wurtzite structures can self-assemble with isotropic in- teractions possessing a strongly
Isosuperconductivity: A nonlocal-nonhamiltonian theory of pairing in high-T{sub c} superconductivity
Animalu, A.O.E. [Univ. of Nigeria, Nsukka (Nigeria)]|[The Institute for Basic Research, Palm Harbor, FL (United States)
1994-08-01T23:59:59.000Z
The author presents a review and reformulation of the author`s recent nonlocal-nonhamiltonian generalization of the standard BCS (Bardeen-Cooper-Schrieffer) theory of electron pairing in superconductors, here called iso-superconductivity or iso-standard model for short, by drawing two analogies. The first analogy is a geometrical (relativistic) one between the internal (isominkowskian) structures of the neutral pion and the Cooper pair envisaged in the generalization; and the second analogy is a dynamical (fluid mechanics) one between the classical Hamilton-Santilli limit of the generalization and its apparent local/nonlocal two-dimensional (London) superfluid mechanics realizations for flows in the CuO{sub 2} planes of the high-T{sub c} cuprate superconductors. By using the analogies and physical considerations, the author elucidates the origins of the interactions responsible for the fluctuations in the iso-characteristics of the electron within the pair due to the mutual overlapping of the paired electron wavefunctions. The fluctuations are defined in terms of a single quantity, namely an integral operator or {open_quotes}iso unit{close_quotes}. 33 refs., 5 figs., 4 tabs.
Modification of the GS LT Paired-end Library Protocol for Constructing Longer Insert Size Libraries
Peng, Ze; Peng, Ze; Hamilton, Matthew; Ting, Sara; Tu, Hank; Goltsman, Eugene; Lapidus, Alla; Lucas, Susan; Cheng, Jan-Fang
2008-05-22T23:59:59.000Z
Paired-end library sequencing has been proven useful in scaffold construction during de novo assembly of genomic sequences. The ability of generating mate pairs with 8 Kb or greater insert sizes is especially important for genomes containing long repeats. While the current 454 GS LT Paired-end library preparation protocol can successfully construct libraries with 3 Kb insert size, it fails to generate longer insert sizes because the protocol is optimized to purify shorter fragments. We have made several changes in the protocol in order to increase the fragment length. These changes include the use of Promega column to increase the yield of large size DNA fragments, two gel purification steps to remove contaminated short fragments, and a large reaction volume in the circularization step to decrease the formation of chimeras. We have also made additional changes in the protocol to increase the overall quality of the libraries. The quality of the libraries are measured by a set of metrics, which include levels of redundant reads, linker positive, linker negative, half linker reads, and driver DNA contamination, and read length distribution, were used to measure the primary quality of these libraries. We have also assessed the quality of the resulted mate pairs including levels of chimera, distribution of insert sizes, and genome coverage after the assemblies are completed. Our data indicated that all these changes have improved the quality of the longer insert size libraries.
Kinetic Energy Driven Pairing in Cuprate Superconductors Th. A. Maier,1
Jarrell, Mark
Kinetic Energy Driven Pairing in Cuprate Superconductors Th. A. Maier,1 M. Jarrell,2 A. Macridin,2, Tennessee 37831-6164, USA 2 Department of Physics, University of Cincinnati, Cincinnati Ohio 45221, USA 3 of the electronic potential energy accompanied by an increase in kinetic energy. In the underdoped cuprates, optical
Tunneling into black hole, escape from black hole, reflection from horizon and pair creation
V. V. Flambaum
2004-08-05T23:59:59.000Z
Within classical general relativity, a particle cannot reach the horizon of a black hole during a finite time, in the reference frame of an external observer; a particle inside cannot escape from a black hole; and the horizon does not produce any reflection. We argue that these processes may possibly be allowed in the quantum world. It is known that quantum mechanics allows pair creation at the horizon (one particle inside, another particle outside) and Hawking radiation. One can extend this idea to propose other processes. Tunneling of an external particle inside black hole may be produced by the creation of a pair at the horizon, followed by the annihilation of one created particle with the initial particle outside, with the other created particle appearing inside. Escape of a particle from a black hole may result from the creation of a pair, followed by the annihilation of one created particle with the particle inside, with the other created particle appearing outside. The escape may allow the transfer of information to the outside.Finally, the reflection of an external particle from the horizon may be modelled by a combination of the two processes presented above. The relationship between these "pair creation-annihilation'' mechanisms and the "horizon tunneling" calculations [1-5] is discussed.
Detecting W/Z pairs and Higgs at high energy pp colliders: Main experimental issues
Alverson, G.; Bengtsson, H.U.; Hauptman, J.; Hedin, D.; Herrero, M.J.; Wang, E.; Linn, S.; Young, C.; Milliken, B.; Paige, F.
1987-03-01T23:59:59.000Z
The main detection issues implied by the search for W and Z/sup 0/ pairs and Higgs in a high energy pp collider context are discussed here. It includes: precise electron identification, missing energy measurement, multilepton recognition, sophisticated jet pattern recognition, and pile-up. The study uses, as much as possible, a ''realistic simulation of life.''
QCD Corrections to Vector Boson Pair Production via Weak Boson Fusion
B. Jager; C. Oleari; D. Zeppenfeld
2006-08-24T23:59:59.000Z
NLO-QCD corrections to vector boson pair production via weak boson fusion have recently been calculated and implemented into flexible parton-level Monte-Carlo programs. These allow for the computation of cross sections and kinematical distributions within realistic experimental cuts. We summarize the basic elements of the calculation and review phenomenological results for the LHC.
Next-to-leading order QCD corrections to light Higgs Pair production via vector boson fusion
Terrance Figy
2008-06-15T23:59:59.000Z
We present the NLO QCD corrections for light Higgs pair production via vector boson fusion at the LHC within the CP conserving type II two higgs doublet model in the form of a fully flexible parton--level Monte Carlo program. Scale dependences on integrated cross sections and distributions are reduced with QCD K-factors of order unity.
Niu, J. G. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Department of Mechanical Engineering, Hebei University, Baoding 071000 (China); Zhan, Q., E-mail: qzhan@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Geng, W. T., E-mail: geng@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Psi Quantum Materials LLC, Laiwu 271100 (China)
2014-06-15T23:59:59.000Z
Despite well documented first-principles theoretical determination of the low migration energy (0.06 eV) of a single He in tungsten, fully quantum mechanical calculations on the migration of a He pair still present a challenge due to the complexity of its trajectory. By identifying the six most stable configurations of the He pair in W and decomposing its motion into rotational, translational, and rotational-translational routines, we are able to determine its migration barrier and trajectory. Our density functional theory calculations demonstrate a He pair has three modes of motion: a close or open circular two-dimensional motion in (100) plane with an energy barrier of 0.30 eV, a snaking motion along [001] direction with a barrier of 0.30 eV, and a twisted-ladder motion along [010] direction with the two He swinging in the plane (100) and a barrier of 0.31 eV. The graceful associative movements of a He pair are related to the chemical-bonding-like He-He interaction being much stronger than its migration barrier in W. The excellent agreement with available experimental measurements (0.240.32 eV) on He migration makes our first-principles result a solid input to obtain accurate He-W interatomic potentials in molecular dynamics simulations.
On the kinetic equation approach to pair production by time-dependent electric field
A. M. Fedotov; E. G. Gelfer; K. Yu. Korolev; S. A. Smolyansky
2010-08-12T23:59:59.000Z
We investigate the quantum kinetic approach to pair production from vacuum by time-dependent electric field. Equivalence between this approach and the more familiar S-matrix approach is explicitly established for both scalar and fermion cases. For the particular case of a constant electric field exact solution for kinetic equations is provided and the accuracy of low-density approximation is estimated.
Chaotic ratchet dynamics with cold atoms in a pair of pulsed optical lattices
Gabriel G. Carlo; Giuliano Benenti; Giulio Casati; Sandro Wimberger; Oliver Morsch; Riccardo Mannella; Ennio Arimondo
2006-07-27T23:59:59.000Z
We present a very simple model for realizing directed transport with cold atoms in a pair of periodically flashed optical lattices. The origin of this ratchet effect is explained and its robustness demonstrated under imperfections typical of cold atom experiments. We conclude that our model offers a clear-cut way to implement directed transport in an atom optical experiment.
Measurement of prompt J/? pair production in pp collisions at ?s = 7 Tev
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan
2014-09-01T23:59:59.000Z
Production of prompt J/? meson pairs in proton-proton collisions at ?s = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb?. The two J/? mesons are fully reconstructed via their decays into ?? ?? pairs. This observation provides for the first time access to the high-transverse-momentum region of J/? pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/? transverse momentum (pTJ/?) and rapidity (|yJ/?|): |yJ/?| morepTJ/? > 6.5 GeV/c, 1.2 J/?| T threshold that scales linearly with |yJ/?| from 6.5 to 4.5 GeV/c, and 1.43 J/?| TJ/? > 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/? pair production is 1.49 0.07 (stat) 0.13 (syst) nb. Different assumptions about the J/? polarization imply modifications to the cross section ranging from -31% to +27%.less
Quasi-stationary states and a classification of the range of pair interactions
Gabrielli, A. [Istituto dei Sistemi Complessi (ISC), CNR, Via dei Taurini 19, Rome (Italy); Joyce, M. [Laboratoire de Physique Nucleaire et Hautes Energies, Universite Pierre et Marie Curie (France); Marcos, B. [Laboratoire J.-A. Dieudonne, Universite de Nice-Sophia Antipolis (France)
2011-03-24T23:59:59.000Z
Systems of long-range interacting particles present typically 'quasi-stationary' states (QSS). Investigating their lifetime for a generic pair interaction V(r{yields}{infinity}){approx}1/r{sup {gamma}} we give a classification of the range of the interactions according to the dynamical properties of the system.
Swigon, David
DNA stretching modeled at the base pair level: Overtwisting and shear instability in elastic Accepted 28 October 2011 Available online 12 November 2011 Keywords: DNA mechanics Overstretching Discrete elastic model Simplex algorithm Bifurcations a b s t r a c t Stretching experiments on single DNA
Donor-vacancy pairs in irradiated n-Ge: A searching look at the problem
Emtsev, Vadim; Oganesyan, Gagik [IoffePhysicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ulitsa 26, 194021 St. Petersburg (Russian Federation)
2014-02-21T23:59:59.000Z
The present situation concerning the identification of vacancy-donor pairs in irradiated n-Ge is discussed. The challenging points are the energy states of these defects deduced from DLTS spectra. Hall effect data seem to be at variance with some important conclusions drawn from DLTS measurements. Critical points of the radiation-produced defect modeling in n-Ge are highlighted.
Adams, R.L. [Sandia National Labs., Albuquerque, NM (United States). Communications Dept.
1994-09-01T23:59:59.000Z
This revision updates Sandia`s working standard for testing optical fiber and unshielded twisted pair cables included in the Lab-wide telecommunications cabling infrastructure. The purpose of these standard testing procedures is to deliver to all Sandians a reliable, low-maintenance, state-of-the-art, ubiquitous telecommunications cabling infrastructure capable of satisfying all current and future telecommunication needs.
Visual Image of Cooper Pairing in Superconductors A. O. E. Animalu
Nigeria Nsukka, Nigeria and Tepper L. Gill Department of Electrical & Computer Engineering Computational-relativistic quasiparticle energy in (k-space) of a Cooper pair, Ek = k 2 + k( ), as an eigenvalue of a 4 4 Hamiltonian construction of a positive energy relativistic wave equation for an integral spin particle. We find a new class
Gckler, Heinz G.
subband-signals by a synthe- sis filter bank (SFB). Due to low battery energy available in hear- ing aidsOVERSAMPLING COMPLEX-MODULATED DIGITAL FILTER BANK PAIRS SUITABLE FOR EXTENSIVE SUBBAND@nt.rub.de, web: www.dsv.rub.de ABSTRACT Oversampling, complex-modulated digital subband coder filter banks
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1
Hagberg, Aric
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1 and Ehud typically evolves into rotating spiral waves. In an anisotropic system, instead of spiral waves, the vortices can form wave fragments that propagate with a constant speed in a given direction determined
Performance comparison of pulse-pair and wavelets methods for the pulse Doppler weather radar
Paris-Sud XI, Universit de
- eters. The radar reflectivity (Z), the radial velocity (Vr) and the spectral width of velocities (W). [1). Generally, the meteorological targets move with speeds lower than 50 m/secs. The Doppler Effect wouldPerformance comparison of pulse-pair and wavelets methods for the pulse Doppler weather radar
Measurement of prompt J/? pair production in pp collisions at ?s = 7 Tev
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan [Yerevan Physics Institute (Armenia)
2014-09-01T23:59:59.000Z
Production of prompt J/? meson pairs in proton-proton collisions at ?s = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb?. The two J/? mesons are fully reconstructed via their decays into ?? ?? pairs. This observation provides for the first time access to the high-transverse-momentum region of J/? pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/? transverse momentum (pTJ/?) and rapidity (|yJ/?|): |yJ/?| TJ/? > 6.5 GeV/c, 1.2 J/?| T threshold that scales linearly with |yJ/?| from 6.5 to 4.5 GeV/c, and 1.43 J/?| TJ/? > 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/? pair production is 1.49 0.07 (stat) 0.13 (syst) nb. Different assumptions about the J/? polarization imply modifications to the cross section ranging from ?31% to +27%.
PHYSICAL REVIEW C 85, 034328 (2012) Pairing dynamics in particle transport
Bertsch George F.
2012-01-01T23:59:59.000Z
PHYSICAL REVIEW C 85, 034328 (2012) Pairing dynamics in particle transport Guillaume Scamps on particle transport in time-dependent theories based on the Hartree-Fock- Bogoliubov (HFB) or BCS in particle densities. This can be ameliorated by freezing the occupation numbers during the evolution in TDHF
Random perturbations of spiking activity in a pair of coupled neurons
Random perturbations of spiking activity in a pair of coupled neurons Boris Gutkin , Jurgen Jost on the firing be- haviour of two coupled Type 1 or Type 2 neurons. In Hodgkin-Huxley model neurons with standard that regular spiking and fast spiking neurons in the rat somatosensory cortex exhibit Type 1 and Type 2 firing
Computer simulation study of liquid CH2F2 with a new effective pair potential model
Mezei, Mihaly
to reproduce the thermodynamic internal energy, density, heat capacity, vapor-liquid equilibrium and structuralComputer simulation study of liquid CH2F2 with a new effective pair potential model Pa potential model is proposed for computer simulations of liquid methylene fluoride and used in Monte Carlo
ENVIRONMENTAL BENZENE EXPOSURE ASSESSMENT FOR PARENT-CHILD PAIRS IN ROUEN, FRANCE
Boyer, Edmond
1 ENVIRONMENTAL BENZENE EXPOSURE ASSESSMENT FOR PARENT-CHILD PAIRS IN ROUEN, FRANCE Amin KOUNIALIa environmental benzene exposure. In this study we compared personal benzene exposure and inhalation uptake in a group of children to those of their parents. We also compared levels of urinary benzene metabolites
Management and Conservation Article Estimation of Successful Breeding Pairs for Wolves in the
Mitchell, Mike
successful breeding pairs will become more difficult following proposed delisting of NRM wolves; alternatives delisting, are required. Because pack size is easier to monitor than pack composition, we estimated where number of packs and their sizes are known. Following delisting of NRM wolves, human
A Distributed Scheme for Efficient Pair-wise Comparison of Complete Genomes
Bansal, Arvind K.
#12;48 A Distributed Scheme for Efficient Pair-wise Comparison of Complete Genomes Valerian S}@mcs.kent.edu 1 Corresponding author Abstract The comparisons of newly sequenced genomes against a genome and a CORBA-based implementation to compare and align gene sequences in large complete genomes, using multiple
Evidence for the 125 GeV Higgs boson decaying to a pair of ? leptons
Apyan, Aram
A search for a standard model Higgs boson decaying into a pair of ? leptons is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012. The dataset corresponds to an integrated luminosity of 4.9 ...
Search for the associated production of the Higgs boson with a top-quark pair
CMS Collaboration
A search for the standard model Higgs boson produced in association with a top-quark pair (ttH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb?1 and 19.7 fb?1 collected in pp ...
Measurement of prompt J/? pair production in pp collisions at ?s = 7 Tev
Khachatryan, Vardan [Yerevan Physics Institute (Armenia)
2014-09-01T23:59:59.000Z
Production of prompt J/? meson pairs in proton-proton collisions at ?s = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb?. The two J/? mesons are fully reconstructed via their decays into ?? ?? pairs. This observation provides for the first time access to the high-transverse-momentum region of J/? pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/? transverse momentum (p_{T}^{J/?}) and rapidity (|y^{J/?}|): |y^{J/?}| < 1.2 for p_{T}^{J/?} > 6.5 GeV/c, 1.2 < |y^{J/?}| < 1.43 for a p_{T} threshold that scales linearly with |y^{J/?}| from 6.5 to 4.5 GeV/c, and 1.43 < |y^{J/?}| < 2.2 for p_{T}^{J/?} > 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/? pair production is 1.49 0.07 (stat) 0.13 (syst) nb. Different assumptions about the J/? polarization imply modifications to the cross section ranging from -31% to +27%.
Pair Production and Radiation Effects in Clouds Illuminated by Gamma Ray Sources
C. D. Dermer; M. Boettcher; E. P. Liang
2001-07-12T23:59:59.000Z
Many classes of gamma-ray sources, such as gamma-ray bursts, blazars, Seyfert galaxies, and galactic black hole sources are surrounded by large amounts of gas and dust. X-rays and gamma-rays that traverse this material will be attenuated by Compton scattering and photoelectric absorption. One signature of an intervening scattering cloud is radiation-hardening by electrons that have been scattered and heated by the incident radiation, as illustrated by a Monte Carlo calculation. Compton scattering provides backscattered photons that will attenuate subsequent gamma rays through \\gamma\\gamma pair-production processes. We calculate the pair efficiency for a cloud illuminated by gamma-ray burst radiation. An analytic calculation of the flux of X-rays and gamma rays Thomson scattered by an intervening cloud is presented. Illuminated clouds near GRBs will form relativistic plasmas containing large numbers of electron-positron pairs that can be detected within ~1-2 days of the explosion before expanding and dissipating. Localized regions of pair annihilation radiation in the Galaxy could reveal gamma-ray sources embedded in dense clouds, or sites of past GRB explosions.
proteinsSTRUCTURE O FUNCTION O BIOINFORMATICS Integrating statistical pair potentials into
Weng, Zhiping
they are typical of many approaches to problems in computational biology. In this work, we have chosen the popularproteinsSTRUCTURE O FUNCTION O BIOINFORMATICS Integrating statistical pair potentials into protein and Zhiping Weng1,2 * 1 Bioinformatics Program Boston University, Massachusetts 02215 2 Biomedical Engineering
proteinsSTRUCTURE O FUNCTION O BIOINFORMATICS Integrating statistical pair potentials into
Weng, Zhiping
they are typical of many approaches to problems in computational biology. In this work, we have chosen the popularproteinsSTRUCTURE O FUNCTION O BIOINFORMATICS Integrating statistical pair potentials into protein , and Zhiping Weng1,2 * 1 Bioinformatics Program Boston University, Massachusetts 02215 2 Biomedical Engineering
Peng, Ze [DOE JGI
2013-01-25T23:59:59.000Z
Ze Peng from DOE JGI presents "Fosmid Cre-LoxP Inverse PCR Paired-End (Fosmid CLIP-PE), a Novel Method for Constructing Fosmid Pair-End Library" at the 7th Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting held in June, 2012 in Santa Fe, NM.
Peng, Ze [DOE JGI] [DOE JGI
2012-06-01T23:59:59.000Z
Ze Peng from DOE JGI presents "Fosmid Cre-LoxP Inverse PCR Paired-End (Fosmid CLIP-PE), a Novel Method for Constructing Fosmid Pair-End Library" at the 7th Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting held in June, 2012 in Santa Fe, NM.
Cohn, Martin
Biphasic Hoxd Gene Expression in Shark Paired Fins Reveals an Ancient Origin of the Distal Limb of expression occurs at later stages of shark fin development, in which Hoxd12 and Hoxd13 are re-expressed along GJ, Cohn MJ (2007) Biphasic Hoxd Gene Expression in Shark Paired Fins Reveals an Ancient Origin
Methods and composition for the production of orthogonal tRNA-aminoacyl tRNA synthetase pairs
Schultz, Peter G. (La Jolla, CA); Wang, Lei (San Diego, CA); Anderson, John Christopher (San Diego, CA); Chin, Jason W. (San Diego, CA); Liu, David R. (Lexington, MA); Magliery, Thomas J. (North Haven, CT); Meggers, Eric L. (Philadelphia, PA); Mehl, Ryan Aaron (San Diego, CA); Pastrnak, Miro (San Diego, CA); Santoro, Stephen William (San Diego, CA); Zhang, Zhiwen (San Diego, CA)
2012-05-08T23:59:59.000Z
This invention provides compositions and methods for generating components of protein biosynthetic machinery including orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases. Methods for identifying orthogonal pairs are also provided. These components can be used to incorporate unnatural amino acids into proteins in vivo.
John, Volker
48 2 Functional Analysis for Linear Saddle Point Problems 2.4 Examples of Pairs of Finite Element Spaces Violating the Discrete Inf-Sup Condition Remark 2.50. On simple pairs of finite element spaces. The simplest and most common finite element spaces are spaces of continuous functions which are piecewise
Four-nucleon alpha-type correlations and proton-neutron pairing away of N=Z line
N. Sandulescu; D. Negrea; C. W. Johnson
2012-09-15T23:59:59.000Z
We study the competition between alpha-type and conventional pair condensation in the ground state of nuclei with neutrons and protons interacting via a charge-independent pairing interaction. The ground state is described by a product of two condensates, one of alpha-like quartets and the other one of pairs in excess relative to the isotope with N=Z. It is shown that this ansatz for the ground state gives very accurate pairing correlation energies for nuclei with the valence nucleons above the closed cores 16O, 40Ca and 100Sn. These results indicate that alpha-type correlations are important not only for the self-conjugate nuclei but also for nuclei away of N=Z line. In the latter case alpha-like quartets coexist with the collective Cooper pairs formed by the nucleons in excess.
Four-nucleon alpha-type correlations and proton-neutron pairing away of N=Z line
Sandulescu, N; Johnson, C W
2012-01-01T23:59:59.000Z
We study the competition between alpha-type and conventional pair condensation in the ground state of nuclei with neutrons and protons interacting via a charge-independent pairing interaction. The ground state is described by a product of two condensates, one of alpha-like quartets and the other one of pairs in excess relative to the isotope with N=Z. It is shown that this ansatz for the ground state gives very accurate pairing correlation energies for nuclei with the valence nucleons above the closed cores 16O, 40Ca and 100Sn. These results indicate that alpha-type correlations are important not only for the self-conjugate nuclei but also for nuclei away of N=Z line. In the latter case alpha-like quartets coexist with the collective Cooper pairs formed by the nucleons in excess.
S. Lin; X. Z. Zhang; Z. Song
2015-01-09T23:59:59.000Z
We study the dynamics of bound pairs in the extended Hubbard model driven by a linear external field. It is shown that two interacting bosons or singlet fermions with nonzero on-site and nearest-neighbor interaction strengths can always form bound pairs in the absence of an external field. There are two bands of bound pairs, one of which may have incomplete wave vectors when it has an overlap with the scattering band, referred to as an imperfect band. In the presence of the external field, the dynamics of the bound pair in the perfect band exhibits distinct Bloch-Zener oscillation (BZO), while in the imperfect band the oscillation presents a sudden death. The pair becomes uncorrelated after the sudden death and the BZO never comes back. Such dynamical behaviors are robust even for the weak-coupling regime and thus can be used to characterize the phase diagram of the bound states.
Search for the standard model Higgs boson in tau lepton pair final states
D0 Collaboration
2012-05-16T23:59:59.000Z
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data corresponding to an integrated luminosity of up to 7.3 fb^{-1} collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau lepton pairs or W boson pairs. Observed (expected) limits are set on the ratio of 95% C.L. upper limits on the cross section times branching ratio, relative to those predicted by the Standard Model, of 14 (22) at a Higgs boson mass of 115 GeV and 7.7 (6.8) at 165 GeV.
Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, Islamabad 44000 (Pakistan); Rizvi, H. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 54000 (Pakistan)
2011-04-15T23:59:59.000Z
Nonlinear electrostatic shock waves are studied in unmagnetized, dissipative pair-ion plasmas. The dissipation in the system is taken into account by considering the effect of kinematic viscosity of both positive and negative ions in plasmas. The system of fluid equations for asymmetric pair-ion plasma is reduced to Korteweg-deVries-Burgers equation in the limit of small amplitude perturbation. It is observed that the system under consideration admits rarefactive shocks. Keeping in view the practical applications, the nonlinear propagation of both the exploding and imploding shocks is investigated and the differences are expounded in detail. The present study may have relevance in the study of the formation of electrostatic shocks in laser-induced implosion devices, star formation, supernovae explosion, etc.
Mushtaq, A. [Theoretical Plasma Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Nilore, Islamabad 45660 (Pakistan); School of Physics, University of Sydney, New South Wales 2006 (Australia); Saeed, R.; Haque, Q. [Theoretical Plasma Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Nilore, Islamabad 45660 (Pakistan)
2011-04-15T23:59:59.000Z
Linear and nonlinear coupled electrostatic drift and ion acoustic waves are studied in inhomogeneous, collisional pair ion-electron plasma. The Korteweg-de Vries-Burgers (KdVB) equation for a medium where both dispersion and dissipation are present is derived. An attempt is made to obtain exact solution of KdVB equation by using modified tanh-coth method for arbitrary velocity of nonlinear drift wave. Another exact solution for KdVB is obtained, which gives a structure of shock wave. Korteweg-de Vries (KdV) and Burgers equations are derived in limiting cases with solitary and monotonic shock solutions, respectively. Effects of species density, magnetic field, obliqueness, and the acoustic to drift velocity ratio on the solitary and shock solutions are investigated. The results discussed are useful in understanding of low frequency electrostatic waves at laboratory pair ion plasmas.
Testing the local-void alternative to dark energy using galaxy pairs
Wang, F Y
2013-01-01T23:59:59.000Z
The possibility that we live in a special place in the universe, close to the center of a large, radially inhomogeneous void, has attracted attention recently as an alternative to dark energy or modified gravity to explain the accelerating universe. We show that the distribution of orientations of galaxy pairs can be used to test the Copernican principle that we are not in a central or special region of Universe. The popular void models can not fit both the latest type Ia supernova, cosmic microwave background data and the distribution of orientations of galaxy pairs simultaneously. Our results rule out the void models at the $4\\sigma$ confidence level as the origin of cosmic acceleration and favor the Copernican principle.
Optical-fiber source of polarization-entangled photon pairs in the 1550nm telecom band
Xiaoying Li; Paul L. Voss; Jay E. Sharping; Prem Kumar
2004-08-12T23:59:59.000Z
We present a fiber based source of polarization-entangled photon pairs that is well suited for quantum communication applications in the 1550nm band of standard fiber-optic telecommunications. Polarization entanglement is created by pumping a nonlinear-fiber Sagnac interferometer with two time-delayed orthogonally-polarized pump pulses and subsequently removing the time distinguishability by passing the parametrically scattered signal-idler photon pairs through a piece of birefringent fiber. Coincidence detection of the signal-idler photons yields biphoton interference with visibility greater than 90%, while no interference is observed in direct detection of either the signal or the idler photons. All four Bell states can be prepared with our setup and we demonstrate violations of CHSH form of Bell's inequalities by up to 10 standard deviations of measurement uncertainty.
The latest results on top quark pair cross-section measurement
Yamauchi, Katsuya; The ATLAS collaboration
2015-01-01T23:59:59.000Z
The latest results on top quark pair production cross-section measurement in proton-proton collisions at $\\sqrt{s} = 7\\ TeV$ and $\\sqrt{s} = 8\\ TeV$ with the ATLAS detector are reported. The inclusive cross-section was measured with 4% of uncertainty using di-lepton e-mu events. The measurement of the differential cross-section as functions of various observables such as transverse momentum and rapidity of the top quark and invariant mass of the pseudo-top-quark pair system including the results in boosted topologies are also reported. These results are compared with the various generators such as Powheg, Alpgen and MC@NLO and the various PDF sets.
On detection of narrow angle e+e- pairs from dark photon decays
Dermenev, A V; Gninenko, S N; Kuleshov, S B; Matveev, V A; Myalkovskiy, V V; Peshekhonov, V D; Poliakov, V A; Savenkov, A A; Tikhomirov, V O; Zhukov, I A
2015-01-01T23:59:59.000Z
A class of models of dark sectors consider new very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam from the CERN SPS. The proposed search scheme suggests detection of the e+e- pairs produced in the A' -> e+e- decay with a very small opening angle. Coordinate chambers based on the thin-wall drift tubes with a minimal material budget and a two-hit resolution for e+ and e- tracks separated by more than 0.5 mm are considered as an option for detecting such pairs.
Finding the first cosmic explosions. III. Pulsational pair-instability supernovae
Whalen, Daniel J.; Smidt, Joseph [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Woosley, S. E. [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Clayton, Victoria 3800 (Australia); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
2014-02-01T23:59:59.000Z
Population III supernovae have been the focus of growing attention because of their potential to directly probe the properties of the first stars, particularly the most energetic events that can be seen at the edge of the observable universe. But until now pulsational pair-instability supernovae, in which explosive thermonuclear burning in massive stars fails to unbind them but can eject their outer layers into space, have been overlooked as cosmic beacons at the earliest redshifts. These shells can later collide and, like Type IIn supernovae, produce superluminous events in the UV at high redshifts that could be detected in the near infrared today. We present numerical simulations of a 110 M {sub ?} pulsational pair-instability explosion done with the Los Alamos radiation hydrodynamics code Radiation Adaptive Grid Eulerian. We find that collisions between consecutive pulsations are visible in the near infrared out to z ? 15-20 and can probe the earliest stellar populations at cosmic dawn.
First Measurement of the Fraction of Top Quark Pair Production Through Gluon-Gluon Fusion
CDF Collaboration; T. Aaltonen
2008-04-08T23:59:59.000Z
We present the first measurement of the fraction of top quark pair production through gluon-gluon fusion. We use 0.96/fb of s**(1/2)=1.96 TeV p-pbar collision data recorded with the CDF II detector at Fermilab. We identify the candidate t-tbar events with a high-energy charged lepton, a neutrino candidate, and four or more jets. Using charged particles with low transverse momentum in t-tbar events, we find the fraction of top quark pair production through gluon-gluon fusion to be 0.07+/-0.14(stat)+/-0.07(syst), corresponding to a 95% confidence level upper limit of 0.33, in agreement with the standard model NLO prediction of 0.15+/-0.05.
Fred Cooper; Gouranga C. Nayak
2006-12-29T23:59:59.000Z
We study the Schwinger mechanism for the pair production of fermions in the presence of an arbitrary time-dependent background electric field E(t) by directly evaluating the path integral. We obtain an exact non-perturbative result for the probability of fermion-antifermion pair production per unit time per unit volume per unit transverse momentum (of the fermion or antifermion) from the arbitrary time dependent electric field E(t) via Schwinger mechanism. We find that the exact non-perturbative result is independent of all the time derivatives d^nE(t)/dt^n, where n=1,2,....\\infty. This result has the same functional dependence on E as the Schwinger's constant electric field E result with the replacement: E -> E(t).
Pair dispersion in a chaotic flow reveals the role of the memory of initial velocity
Afik, Eldad
2015-01-01T23:59:59.000Z
The leading paradigm for chaotic flows dominated by dissipation predicts an exponential growth of the mean distance between pairs of fluid elements, in the long run. This is reflected in the analysis of experimental results on tracer particles and the discussions which follow, as reported in recent experimental and numerical publications. To quantitatively validate this prediction, we have conducted a microfluidic experiment generating elastic turbulence, a flow characterised in the literature as smooth in space and random in time. To our great surprise, we discovered that the pair separation follows a much slower power-law --- also known as ballistic --- a notion overlooked so far for flows of this type. We provide conclusive experimental evidence that this scaling is well-desribed by the same coefficients derived from the short-time dynamics. Our finding reinforces the role of the ballistic regime over a significant range in time and space, providing a quantitative estimation for the spreading of particles ...
Observation of ?_{c1} Decays into Vector Meson Pairs ??, ?? and, ??
Ablikim, M.; Achasov, M. N.; An, L.; An, Q.; An, Z. H.; Bai, J. Z.; Baldini, R.; Ban, Y.; Becker, J.; Berger, N.; Bertani, M.; Bian, J. M.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cao, G. F.; Cao, X. X.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denysenko, I.; Destefanis, M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Duan, M. Y.; Fan, R. R.; Fang, J.; Fang, S. S.; Feng, C. Q.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Greco, M.; Grishin, S.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, B.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jia, L. K.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kavatsyuk, M.; Komamiya, S.; Kuehn, W.; Lange, J. S.; Leung, J. K. C.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, Lei; Li, N. B.; Li, Q. J.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, G. C.; Liu, H.; Liu, H. B.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K.; Liu, K. Y.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Y. W.; Liu, Yong; Liu, Z. A.; Liu, Z. Q.; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, T.; Ma, X.; Ma, X. Y.; Maggiora, M.; Malik, Q. A.; Mao, H.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Muchnoi, N. Yu.; Nefedov, Y.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pelizaeus, M.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Pun, C. S. J.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, X. Y.; Sonoda, S.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. D.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tang, X. F.; Tian, H. L.; Toth, D.; Varner, G. S.; Wan, X.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Wen, Q. G.; Wen, S. P.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, W.; Wu, Z.; Xiao, Z. J.; Xie, Y. G.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Y.; Xu, Z. R.; Xu, Z. Z.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, M.; Yang, T.; Yang, Y.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, L.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, L.; Zhang, S. H.; Zhang, T. R.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, Jiawei; Zhao, Jingwei; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhao, Z. L.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zheng, Z. P.; Zhong, B.; Zhong, J.; Zhong, L.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Zuo, J. X.; Zweber, P.
2011-08-01T23:59:59.000Z
Using (1064)10? ?(3686) events accumulated with the BESIII detector at the BEPCII e?e? collider, we present the first measurement of decays of ?_{c1} to vector meson pairs ??, ??, and ??. The branching fractions are measured to be (4.40.30.5)10??, (6.00.30.7)10??, and (2.20.60.2)10??, for ?_{c1} ???, ??, and ??, respectively, which indicates that the hadron helicity selection rule is significantly violated in ?_{cJ} decays. In addition, the measurement of ?_{cJ}??? provides the first indication of the rate of doubly OZI-suppressed ?_{cJ} decay. Finally, we present improved measurements for the branching fractions of ?_{c0} and ?_{c2} to vector meson pairs.
Auxiliary-field quantum Monte Carlo method for strongly paired fermions
Carlson, J.; Gandolfi, Stefano [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Schmidt, Kevin E. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Zhang, Shiwei [Department of Physics, College of William and Mary, Williamsburg, Virginia 23187 (United States)
2011-12-15T23:59:59.000Z
We solve the zero-temperature unitary Fermi gas problem by incorporating a BCS importance function into the auxiliary-field quantum Monte Carlo method. We demonstrate that this method does not suffer from a sign problem and that it increases the efficiency of standard techniques by many orders of magnitude for strongly paired fermions. We calculate the ground-state energies exactly for unpolarized systems with up to 66 particles on lattices of up to 27{sup 3} sites, obtaining an accurate result for the universal parameter {xi}. We also obtain results for interactions with different effective ranges and find that the energy is consistent with a universal linear dependence on the product of the Fermi momentum and the effective range. This method will have many applications in superfluid cold atom systems and in both electronic and nuclear structures where pairing is important.
Nonlinear pair production in scattering of photons on ultra-short laser pulses at high energy
Tuchin, Kirill
2009-01-01T23:59:59.000Z
We consider scattering of a photon on a short intense laser pulse at high energy. We argue that for ultra-short laser pulses the interaction is coherent over the entire length of the pulse. At low pulse intensity $I$ the total cross section for electron-positron pair production is proportional to $I$. However, at pulse intensities higher than the characteristic value $I_s$, the total cross section saturates -- it becomes proportional to the logarithm of intensity. This nonlinear effect is due to multi-photon interactions. We derive the total cross section for pair production at high energies by resuming the multi-photon amplitudes to all orders in intensity. We calculate the saturation intensity $I_s$ and show that it is significantly lower than the Schwinger's critical value. We discuss possible experimental tests.
Parity violating radiative emission of neutrino pair in heavy alkaline earth atoms of even isotopes
M. Yoshimura; N. Sasao; S. Uetake
2014-03-26T23:59:59.000Z
Metastable excited states ${}^3P_2, {}^3P_0$ of heavy alkaline earth atoms of even isotopes are studied for parity violating (PV) effects in radiative emission of neutrino pair (RENP). PV terms arise from interference between two diagrams containing neutrino pair emission of valence spin current and nuclear electroweak charge density proportional to the number of neutrons in nucleus. This mechanism gives large PV effects, since it does not suffer from the suppression of 1/(electron mass) usually present for non-relativistic atomic electrons. A controllable magnetic field is crucial to identify RENP process by measuring PV observables. Results of PV asymmetries under the magnetic field reversal and the photon circular polarization reversal are presented for an example of Yb atom.
Two-step quantum direct communication protocol using the Einstein-Podolsky-Rosen pair block
Deng Fuguo; Liu Xiaoshu [Department of Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory For Quantum Information and Measurements, Beijing 100084 (China); Long Guilu [Department of Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory For Quantum Information and Measurements, Beijing 100084 (China); Center for Atomic and Molecular NanoSciences, Tsinghua University, Beijing 100084 (China); Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080 (China)
2003-10-01T23:59:59.000Z
A protocol for quantum secure direct communication using blocks of Einstein-Podolsky-Rosen (EPR) pairs is proposed. A set of ordered N EPR pairs is used as a data block for sending secret message directly. The ordered N EPR set is divided into two particle sequences, a checking sequence and a message-coding sequence. After transmitting the checking sequence, the two parties of communication check eavesdropping by measuring a fraction of particles randomly chosen, with random choice of two sets of measuring bases. After insuring the security of the quantum channel, the sender Alice encodes the secret message directly on the message-coding sequence and sends them to Bob. By combining the checking and message-coding sequences together, Bob is able to read out the encoded messages directly. The scheme is secure because an eavesdropper cannot get both sequences simultaneously. We also discuss issues in a noisy channel.
Nonlinear pair production in scattering of photons on ultra-short laser pulses at high energy
Kirill Tuchin
2010-02-15T23:59:59.000Z
We consider scattering of a photon on a short intense laser pulse at high energy. We argue that for ultra-short laser pulses the interaction is coherent over the entire length of the pulse. At low pulse intensity $I$ the total cross section for electron-positron pair production is proportional to $I$. However, at pulse intensities higher than the characteristic value $I_s$, the total cross section saturates -- it becomes proportional to the logarithm of intensity. This nonlinear effect is due to multi-photon interactions. We derive the total cross section for pair production at high energies by resuming the multi-photon amplitudes to all orders in intensity. We calculate the saturation intensity $I_s$ and show that it is significantly lower than the Schwinger's critical value. We discuss possible experimental tests.
Borisov, A. V.; Kerimov, B. K.; Sizin, P. E., E-mail: borisov@phys.msu.ru [Moscow State University (Russian Federation)
2012-11-15T23:59:59.000Z
Expressions for the power of neutrino radiation from a degenerate electron gas in a strong magnetic field are derived for the case of neutrino-pair photoproduction via the weak and electromagnetic interaction mechanisms (it is assumed that the neutrino possesses electromagnetic form factors). It is shown that the neutrino luminosity of a medium in the electromagnetic reaction channel may exceed substantially the luminosity in the weak channel. Relative upper bounds on the effective neutrino magnetic moment are obtained.
X-shooter Science Verification Proposal A special co-moving white dwarfmain sequence pair
Liske, Jochen
and HD 122750 form a co-moving proper motion pair (PM in mas/yr: RA, Dec, from UCAC-2): WD 1401-147 (-170: The white dwarf (WD) WD 1401-147 and the main sequence (MS) star HD 122750 form a co-moving proper motion laboratory to study the complex physics of pulsating WDs in a quantitative manner. Scientific Case: WD 1401-147
Two-color ghost interference with photon pairs generated in hot atoms
Ding Dongsheng; Zhou Zhiyuan; Shi Baosen; Zou Xubo; Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026 (China)
2012-09-15T23:59:59.000Z
We report on an experimental observation of a two-photon ghost interference experiment. A distinguishing feature of our experiment is that the photons are generated via a non-degenerated spontaneous four-wave mixing process in a hot atomic ensemble; therefore the photon has narrow bandwidth. Besides, there is a large difference in frequency between two photons in a pair. Our works may be important to achieve more secure, large transmission capacity long-distance quantum communication.
Pure-state dynamics of a pair of charge qubits in a random environment
Buric, Nikola [Department of Physics and Mathematics, Faculty of Pharmacy, University of Beograd, Vojvode Stepe 450, Belgrade (Serbia and Montenegro)
2005-10-15T23:59:59.000Z
A pair of charge qubits in a random electromagnetic environment is studied, using the description of the random dynamics of its pure-state vector as given by quantum-state diffusion theory. It is shown by numerical computations that the pure-state dynamics provides a more detailed description than the density-matrix picture of the main effects such as phase dumping and depolarization.
Next-to-leading order QCD corrections to slepton pair production via vector-boson fusion
Partha Konar; Dieter Zeppenfeld
2006-12-11T23:59:59.000Z
Slepton pairs can be produced in vector-boson fusion processes at hadron colliders. The next-to-leading order QCD corrections to the electroweak production cross section for p p -> slepton+ slepton- +2jets at order alpha_s alpha^4 have been calculated and implemented in a NLO parton-level Monte Carlo program. Numerical results are presented for the CERN Large Hadron Collider.
Thomas Garrity
2012-05-25T23:59:59.000Z
A new classification scheme for pairs of real numbers is given, generalizing earlier work of the author that used continued fraction, which in turn was motivated by ideas from statistical mechanics in general and work of Knauf and Fiala and Kleban in particular. Critical for this classification are the number theoretic and geometric properties of the triangle map, a type of multi-dimensional continued fraction.
Relativistic Quantization of Cooper Pairs and Distributed Electrons in Rotating Superconductors
I. E. Bulyzhenkov
2009-07-02T23:59:59.000Z
Relativistic time synchronization along closed integral lines maintains magnetic flux quantization independently from gravitation. All Fermi-volume electrons form time-averaged electromagnetic fields within rotating conductors, while Fermi-surface superelectrons enable flux quantization in SQUID experiments. Inertia is not related to instantaneous self-coherent states of the distributed electric charge and, therefore, the Cooper pair mass can not be measured in principle from magnetic flux quantization.
Two pairs of interacting EBs towards the LMC in the OGLE database
Aviv Ofir
2008-12-17T23:59:59.000Z
A single point source on the OGLE LMC database shows the characteristics of two superimposed eclipsing binaries (EBs). The two EBs happen to have periods very close to the 3:2 resonance. The telescope's small PSF and the apparent resonance between the two EBs raises the suspicion that this is not chance alignment but rather a compact hierarchical system of two pairs of interacting EBs in 3:2 resonance.
Contributions of different neutron pairs in different approaches for neutrinoless double beta decay
Alberto Escuderos; Amand Faessler; Vadim Rodin; Fedor Simkovic
2010-06-07T23:59:59.000Z
The methods used till now to calculate the neutrinoless double beta decay matrix elements are: the Quasiparticle Random Phase Approximation (QRPA), the Shell Model (SM), the angular momentum projected Hartee-Fock-Bogoliubov approach (HFB) and the Interacting Boson Model (IBM). The different approaches are compared specifically concerning the the angular momenta and parities of the neutron pairs, which are changed into two protons by the $0\
Electron-Positron Pair Production by an Electron in a Magnetic Field Near the Process Threshold
O. P. Novak; R. I. Kholodov; P. I. Fomin
2011-01-13T23:59:59.000Z
The electron-positron pair production by an electron in a strong magnetic field near the process threshold is considered. The process is shown to be more probable if the spin of the initial electron is oriented along the field. In this case, the probability of the process is $\\sim10^{13} s^{-1}$ when the magnetic field strength is $H=4\\cdot 10^{12}$ G.
mTGen: mass scale measurements in pair-production at colliders
Lester, Christopher G; Barr, Alan
2007-01-01T23:59:59.000Z
ar X iv :0 70 8. 10 28 v4 [ he p- ph ] 6 A ug 20 09 Cavendish-HEP-2007-05 PACS: 13.85.Hd 13.85.-t 11.30.Pb 11.80.Cr 12.60.-i mTGen : Mass scale measurements in pair-production at colliders Christopher G. Lester and Alan J. Barr Cavendish...
N. N. Ajitanand; J. M. Alexander; P. Chung; W. G. Holzmann; M. Issah; Roy A. Lacey; A. Shevel; A. Taranenko; P. Danielewicz
2005-06-14T23:59:59.000Z
Methodology is presented for analysis of two-particle azimuthal angle correlation functions obtained in collisions at ultra-relativistic energies. We show that harmonic and di-jet contributions to these correlation functions can be reliably decomposed by two techniques to give an accurate measurement of the jet-pair distribution. Results from detailed Monte Carlo simulations are used to demonstrate the efficacy of these techniques in the study of possible modifications to jet topologies in heavy ion reactions.
STUDYING INTERCLUSTER GALAXY FILAMENTS THROUGH STACKING gmBCG GALAXY CLUSTER PAIRS
Zhang Yuanyuan; Dietrich, Joerg P.; McKay, Timothy A.; Nguyen, Alex T. Q. [Department of Physics, University of Michigan, Ann Arbor, MI (United States); Sheldon, Erin S. [Brookhaven National Laboratory, Upton, NY (United States)
2013-08-20T23:59:59.000Z
We present a method to study the photometric properties of galaxies in filaments by stacking the galaxy populations between pairs of galaxy clusters. Using Sloan Digital Sky Survey data, this method can detect the intercluster filament galaxy overdensity with a significance of {approx}5{sigma} out to z = 0.40. Using this approach, we study the g - r color and luminosity distribution of filament galaxies as a function of redshift. Consistent with expectation, filament galaxies are bimodal in their color distribution and contain a larger blue galaxy population than clusters. Filament galaxies are also generally fainter than cluster galaxies. More interestingly, the observed filament population seems to show redshift evolution at 0.12 < z < 0.40: the blue galaxy fraction has a trend to increase at higher redshift; such evolution is parallel to the ''Butcher-Oemler effect'' of galaxy clusters. We test the dependence of the observed filament density on the richness of the cluster pair: richer clusters are connected by higher density filaments. We also test the spatial dependence of filament galaxy overdensity: this quantity decreases when moving away from the intercluster axis between a cluster pair. This method provides an economical way to probe the photometric properties of filament galaxies and should prove useful for upcoming projects like the Dark Energy Survey.
Non-astigmatic imaging with matched pairs of spherically bent reflectors
Bitter, Manfred Ludwig (Princeton, NJ); Hill, Kenneth Wayne (Plainsboro, NJ); Scott, Steven Douglas (Wellesley, MA); Feder, Russell (Newton, PA); Ko, Jinseok (Cambridge, MA); Rice, John E. (N. Billerica, MA); Ince-Cushman, Alexander Charles (New York, NY); Jones, Frank (Manalapan, NJ)
2012-07-10T23:59:59.000Z
Arrangements for the point-to-point imaging of a broad spectrum of electromagnetic radiation and ultrasound at large angles of incidence employ matched pairs of spherically bent reflectors to eliminate astigmatic imaging errors. Matched pairs of spherically bent crystals or spherically bent multi-layers are used for X-rays and EUV radiation; and matched pairs of spherically bent mirrors that are appropriate for the type of radiation are used with microwaves, infrared and visible light, or ultrasound. The arrangements encompass the two cases, where the Bragg angle--the complement to the angle of incidence in optics--is between 45.degree. and 90.degree. on both crystals/mirrors or between 0.degree. and 45.degree. on the first crystal/mirror and between 45.degree. and 90.degree. on the second crystal/mirror, where the angles of convergence and divergence are equal. For x-rays and EUV radiation, also the Bragg condition is satisfied on both spherically bent crystals/multi-layers.
Neutrino pair emission due to scattering of electrons off fluxoids in superfluid neutron star cores
A. D. Kaminker; D. G. Yakovlev; P. Haensel
1997-02-18T23:59:59.000Z
We study the emission of neutrinos, resulting from the scattering of electrons off magnetic flux tubes (fluxoids) in the neutron star cores with superfluid (superconducting) protons. In the absence of proton superfluidity (T> T_{cp}), this process transforms into the well known electron synchrotron emission of neutrino pairs in a locally uniform magnetic field B, with the neutrino energy loss rate Q proportional to B^2 T^5. For temperatures T not much below T_{cp}, the synchrotron regime (Q \\propto T^5) persists and the emissivity Q can be amplified by several orders of magnitude due to the appearance of the fluxoids and associated enhancement of the field within them. For lower T, the synchrotron regime transforms into the bremsstrahlung regime (Q \\propto T^6) similar to the ordinary neutrino-pair bremsstrahlung of electrons which scatter off atomic nuclei. We calculate Q numerically and represent our results through a suitable analytic fit. In addition, we estimate the emissivities of two other neutrino-production mechanisms which are usually neglected -- neutrino-pair bremsstrahlung processes due to electron-proton and electron-electron collisions. We show that the electron-fluxoid and electron-electron scattering can provide the main neutrino production mechanisms in the neutron star cores with highly superfluid protons and neutrons at T scattering is significant if the initial, locally uniform magnetic field B > 10^{13} G.
Pair Production of Heavy Quarkonium and $B_c(^*)$ Mesons at Hadron Colliders
Rong Li; Yu-Jie Zhang; Kuang-Ta Chao
2009-03-12T23:59:59.000Z
We investigate the pair production of S-wave heavy quarkonium at the LHC in the color-singlet mechanism (CSM) and estimate the contribution from the gluon fragmentation process in the color-octet mechanism (COM) for comparison. With the matrix elements extracted previously in the leading order calculations, the numerical results show that the production rates are quite large for the pair production processes at the LHC. The $p_t$ distribution of double $J/\\psi$ production in the CSM is dominant over that in the COM when $p_t$ is smaller than about 8GeV. For the production of double $\\Upsilon$, the contribution of the COM is always larger than that in the CSM. The large differences in the theoretical predictions between the CSM and COM for the $p_t$ distributions in the large $p_t$ region are useful in clarifying the effects of COM on the quarkonium production. We also investigate the pair production of S-wave $B_c$ and $B_c^*$ mesons, and the measurement of these processes is useful to test the CSM and extract the LDMEs for the $B_c$ and $B_c^*$ mesons.
Pair Production from Vacuum at the Focus of an X-Ray Free Electron Laser
A. Ringwald
2001-03-16T23:59:59.000Z
There are definite plans for the construction of X-ray free electron lasers (FEL), both at DESY, where the so-called XFEL is part of the design of the electron-positron linear collider TESLA, as well as at SLAC, where the so-called Linac Coherent Light Source (LCLS) has been proposed. Such an X-ray laser would allow for high-field science applications: One could make use of not only the high energy and transverse coherence of the X-ray beam, but also of the possibility of focusing it to a spot with a small radius, hopefully in the range of the laser wavelength. Along this route one obtains very large electric fields, much larger than those obtainable with any optical laser of the same power. In this letter we discuss the possibility of obtaining an electric field so high that electron-positron pairs are spontaneously produced in vacuum (Schwinger pair production). We find that if X-ray optics can be improved to approach the diffraction limit of focusing, and if the power of the planned X-ray FELs can be increased to the terawatt region, then there is ample room for an investigation of the Schwinger pair production mechanism.
Vacuum pair production of charged scalar bosons in time-dependent electric fields
Zi-Liang Li; Ding Lu; Bai-Song Xie
2013-12-10T23:59:59.000Z
Based on the quantum mechanical scattering model, the dynamical assist effect and the multiple-slit interference effect in electron-positron pair production from vacuum are generalized to vacuum pair production of charged scalar bosons. For the former effect some combinations of a strong but slowly varying electric field and a weak but rapidly varying one with different time delay are studied. Results indicate that the oscillation intensity of momentum spectrum and the number density of created bosons reduce with increasing of the time delay. Obviously, they achieve the maximum if the time delay equals zero. For the latter effect, it is shown that this effect does not exist for equal-sign $N$-pulse electric field in contrast to its existence for alternating-sign $N$-pulse. An approximate solution of boson momentum spectrum is got and it is agreeable well with the exact numerical one in alternating-sign $N$-pulse electric field, especially for $2$-pulse field and for small longitudinal momentum. The difference of vacuum pair production between bosons and fermions are also compared for their longitudinal momentum spectra.
Pair dispersion in a chaotic flow reveals the role of the memory of initial velocity
Eldad Afik; Victor Steinberg
2015-02-10T23:59:59.000Z
The leading paradigm for chaotic flows dominated by dissipation predicts an exponential growth of the mean distance between pairs of fluid elements, in the long run. This is reflected in the analysis of experimental results on tracer particles and the discussions which follow, as reported in recent experimental and numerical publications. To quantitatively validate this prediction, we have conducted a microfluidic experiment generating elastic turbulence, a flow characterised in the literature as smooth in space and random in time. To our great surprise, we discovered that the pair separation follows a much slower power-law --- also known as ballistic --- a notion overlooked so far for flows of this type. We provide conclusive experimental evidence that this scaling is well-desribed by the same coefficients derived from the short-time dynamics. Our finding reinforces the role of the ballistic regime over a significant range in time and space, providing a quantitative estimation for the spreading of particles in mixing microfluidic flows based on the initial velocity snapshot. Finally we note that the conditions for the asymptotic exponential pair separation are quite stringent when it comes to tracer particles and are unlikely to be realised in wall-bounded flows. Therefore this work raises questions regarding the relevance and applicability of the currently leading paradigm.
Li, Wei; Harrington, Richard; Tang, Yuanzhi; Kubicki, James D.; Aryanpour, Masoud; Reeder, Richard J.; Parise, John B.; Phillips, Brian L. (SBU); (Penn)
2012-03-15T23:59:59.000Z
Structural information is important for understanding surface adsorption mechanisms of contaminants on metal (hydr)oxides. In this work, a novel technique was employed to study the interfacial structure of arsenate oxyanions adsorbed on {gamma}-alumina nanoparticles, namely, differential pair distribution function (d-PDF) analysis of synchrotron X-ray total scattering. The d-PDF is the difference of properly normalized PDFs obtained for samples with and without arsenate adsorbed, otherwise identically prepared. The real space pattern contains information on atomic pair correlations between adsorbed arsenate and the atoms on {gamma}-alumina surface (Al, O, etc.). PDF results on the arsenate adsorption sample on {gamma}-alumina prepared at 1 mM As concentration and pH 5 revealed two peaks at 1.66 {angstrom} and 3.09 {angstrom}, corresponding to As-O and As-Al atomic pair correlations. This observation is consistent with those measured by extended X-ray absorption fine structure (EXAFS) spectroscopy, which suggests a first shell of As-O at 1.69 {+-} 0.01 {angstrom} with a coordination number of 4 and a second shell of As-Al at 3.13 {+-} 0.04 {angstrom} with a coordination number of 2. These results are in agreement with a bidentate binuclear coordination environment to the octahedral Al of {gamma}-alumina as predicted by density functional theory (DFT) calculation.
A new measure of phase synchronization for a pair of time series and seizure focus localization
Kaushik Majumdar
2006-12-22T23:59:59.000Z
Defining and measuring phase synchronization in a pair of nonlinear time series are highly nontrivial. This can be done with the help of Fourier transform, when it exists, for a pair of stored (hence stationary) signals. In a time series instantaneous phase is often defined with the help of Hilbert transform. In this paper phase of a time series has been defined with the help of Fourier transform. This gives rise to a deterministic method to detect phase synchronization in its most general form between a pair of time series. Since this is a stricter method than the statistical methods based on instantaneous phase, this can be used for lateralization and source localization of epileptic seizures with greater accuracy. Based on this method a novel measure of phase synchronization, called syn function, has been defined, which is capable of quantifying neural phase synchronization and asynchronization as important parameters of epileptic seizure dynamics. It has been shown that such a strict measure of phase synchronization has potential application in seizure focus localization from scalp electroencephalogram (EEG) data, without any knowledge of electrical conductivity of the head.
Llordes, Anna [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Gazquez, J. [Oak Ridge National Laboratory (ORNL); Coll, M. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Ye, S. [ICMAB, Barcelona, Spain; Rouco, V [ICMAB, Barcelona, Spain; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Chataigner, D. [CRISMAT, Caen, France; Vanacken, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Gutierrez, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Deutscher, G. [Tel Aviv University; Magen Dominguez, Cesar [ORNL; Obradors, Xavier [ICMAB, Barcelona, Spain
2012-01-01T23:59:59.000Z
Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centers in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.
${\\mathbb{Z}}_N$ graded discrete Lax pairs and discrete integrable systems
Allan P. Fordy; Pavlos Xenitidis
2014-11-22T23:59:59.000Z
We introduce a class of ${\\mathbb{Z}}_N$ graded discrete Lax pairs, with $N\\times N$ matrices, linear in the spectral parameter. We give a classification scheme for such Lax pairs and the associated discrete integrable systems. We present two potential forms and completely classify the generic case. Many well known examples belong to our scheme for $N=2$, so many of our systems may be regarded as generalisations of these. Even at $N=3$, several new integrable systems arise. Many of our equations are mutually compatible, so can be used together to form "coloured" lattices. We also present continuous isospectral deformations of our Lax pairs, giving compatible differential-difference systems, which play the role of continuous symmetries of our discrete systems. We present master symmetries and a recursive formulae for their respective hierarchies, for the generic case. We present two nonlocal symmetries of our discrete systems, which have a natural representation in terms of the potential forms. These give rise to the two-dimensional Toda lattice, with our nonlinear symmetries being the B\\"acklund transformations and our discrete system being the nonlinear superposition formula (for the generic case).
Nuclear pairing from microscopic forces: singlet channels and higher-partial waves
S. Maurizio; J. W. Holt; P. Finelli
2014-08-26T23:59:59.000Z
Background: An accurate description of nuclear pairing gaps is extremely important for understanding static and dynamic properties of the inner crusts of neutron stars and to explain their cooling process. Purpose: We plan to study the behavior of the pairing gaps $\\Delta_F$ as a function of the Fermi momentum $k_F$ for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations will employ realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. Methods: The superfluid states of neutron and nuclear matter are studied by solving the BCS gap equation for chiral nuclear potentials using the method suggested by Khodel et al., where the original gap equation is replaced by a coupled set of equations for the dimensionless gap function $\\chi(p)$ defined by $\\Delta(p) = \\Delta_F \\chi(p)$ and a non-linear algebraic equation for the gap magnitude $\\Delta_F = \\Delta(p_F)$ at the Fermi surface. This method is numerically stable even for small pairing gaps, such as that encountered in the coupled $^3PF_2$ partial wave. Results: We have successfully applied Khodel's method to singlet ($S$) and coupled channel ($SD$ and $PF$) cases in neutron and nuclear matter. Our calculations agree with other ab-initio approaches, where available, and provide crucial inputs for future applications in superfluid systems.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Mani, Tomoyasu; Grills, David C.; Miller, John R.
2015-01-28T23:59:59.000Z
A recently-developed instrument for time-resolved infrared detection following pulse radiolysis has been used to measure the ?(C?N) IR band of the radical anion of a CN-substituted fluorene in tetrahydrofuran. Specific vibrational frequencies can exhibit distinct frequency shifts due to ion-pairing, which can be explained in the framework of the vibrational Stark effect. Measurements of the ratio of free ions and ion-pairs in different electrolyte concentrations allowed us to obtain an association constant and free energy change for ion-pairing. This new method has the potential to probe the geometry of ion-pairing and allows the reduction potentials of molecules to be determinedmorein the absence of electrolyte in an environment of low dielectric constant.less
Constraints on the Higgs boson width from off-shell production and decay to Z-boson pairs
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan; et al.,
2014-09-01T23:59:59.000Z
Constraints are presented on the total width of the recently discovered Higgs boson, Gamma[H], using its relative on-shell and off-shell production and decay rates to a pair of Z bosons, where one Z boson decays to an electron or muon pair, and the other to an electron, muon, or neutrino pair. The analysis is based on the data collected by the CMS experiment at the LHC in 2011 and 2012, corresponding to integrated luminosities of 5.1 inverse femtobarns at a centre-of-mass energy sqrt(s) = 7 TeV and 19.7 inverse femtobarns at sqrt(s) = 8 TeV. A simultaneous maximum likelihood fitmoreto the measured kinematic distributions near the resonance peak and above the Z-boson pair production threshold leads to an upper limit on the Higgs boson width of Gamma[H] less
2009-01-01T23:59:59.000Z
2002). Gene expression profile of human bone marrow stromal2003). Gene expression profile of mouse bone marrow stromalRNA (ncRNA) expression profiles of MSC from match-paired UC
Popovych, Roman
]). Terwilliger showed [5, 10] that a Leonard pair X, Y satisfies a certain algebraic relations with respect to commutators. In turn, the Terwilliger relations follow from to the so-called relations of the AW
Narrow Band Source of Transform-Limited Photon Pairs via Four-Wave Mixing in a Cold Atomic Ensemble
Bharath Srivathsan; Gurpreet Kaur Gulati; Chng Mei Yuen Brenda; Gleb Maslennikov; Dzmitry Matsukevich; Christian Kurtsiefer
2013-09-18T23:59:59.000Z
We observe narrowband pairs of time-correlated photons of wavelengths 776\\,nm and 795\\,nm from non-degenerate four-wave mixing in a laser-cooled atomic ensemble of $^{87}${Rb} using a cascade decay scheme. Coupling the photon pairs into single mode fibers, we observe an instantaneous rate of 7700 pairs per second with silicon avalanche photodetectors, and an optical bandwidth below 30\\,MHz. Detection events exhibit a strong correlation in time ($g^{(2)}(\\tau=0)\\approx5800$), and a high coupling efficiency indicated by a pair-to-single ratio of 23%. The violation of the Cauchy-Schwarz inequality by a factor of $8.4\\times10^6$ indicates a strong non-classical correlation between the generated fields, while a Hanbury--Brown--Twiss experiment in the individual photons reveals their thermal nature. The narrow bandwidth and brightness of our source makes it ideal for interacting with atomic ensembles in quantum communication protocols.
Gomez-Ceballos, Guillelmo
We measure the inclusive forwardbackward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in protonantiproton collisions and decaying to final states that contain two charged leptons (electrons ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Mani, Tomoyasu [Brookhaven National Lab. (BNL), Upton, NY (United States); Grills, David C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Miller, John R. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2015-01-28T23:59:59.000Z
A recently-developed instrument for time-resolved infrared detection following pulse radiolysis has been used to measure the ?(C?N) IR band of the radical anion of a CN-substituted fluorene in tetrahydrofuran. Specific vibrational frequencies can exhibit distinct frequency shifts due to ion-pairing, which can be explained in the framework of the vibrational Stark effect. Measurements of the ratio of free ions and ion-pairs in different electrolyte concentrations allowed us to obtain an association constant and free energy change for ion-pairing. This new method has the potential to probe the geometry of ion-pairing and allows the reduction potentials of molecules to be determined in the absence of electrolyte in an environment of low dielectric constant.
Aggelen, Helen van [Department of Inorganic and Physical Chemistry, Ghent University, Ghent (Belgium) [Department of Inorganic and Physical Chemistry, Ghent University, Ghent (Belgium); Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Yang [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States)] [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Weitao [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)] [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)
2014-05-14T23:59:59.000Z
Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H{sub 2}, and eliminates delocalization errors in H{sub 2}{sup +} and other single-bond systems. It gives surprisingly good non-bonded interaction energies competitive with the ph-RPA with the correct R{sup ?6} asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations.
Particle Acceleration Zones Above Pulsar Polar Caps: Electron and Positron Pair Formation Fronts
Alice K. Harding; Alexander G. Muslimov
1998-05-11T23:59:59.000Z
We investigate self-consistent particle acceleration near a pulsar polar cap (PC) by the electrostatic field due to the effect of inertial frame dragging. Test particles gain energy from the electric field parallel to the open magnetic field lines and lose energy by both curvature radiation (CR) and resonant and non-resonant inverse Compton scattering (ICS) with soft thermal X-rays from the neutron star (NS) surface. Gamma-rays radiated by electrons accelerated from the stellar surface produce pairs in the strong magnetic field, which screen the electric field beyond a pair formation front (PFF). Some of the created positrons can be accelerated back toward the surface and produce gamma-rays and pairs that create another PFF above the surface. We find that ICS photons control PFF formation near the surface, but due to the different angles at which the electron and positron scatter the soft photons, positron initiated cascades develop above the surface and screen the accelerating electric field. Stable acceleration from the NS surface is therefore not possible in the presence of dominant ICS energy losses. However, we find that stable acceleration zones may occur at some distance above the surface, where CR dominates the electron and positron energy losses, and there is up-down symmetry between the electron and positron PFFs. We examine the dependence of CR-controlled acceleration zone voltage, width and height above the surface on parameters of the pulsar and its soft X-ray emission. For most pulsars, we find that acceleration will start at a height of 0.5 - 1 stellar radii above the NS surface.
Vacuum Potentials for the Two Only Permanent Free Particles, Proton and Electron. Pair Productions
J. X. Zheng-Johansson
2015-02-26T23:59:59.000Z
The two only species of isolatable, smallest, or unit charges +e and -e present in nature interact with the universal vacuum in a polarisable dielectric representation through two uniquely defined vacuum potential functions. All of the non-composite subatomic particles containing one-unit charges, +e or -e, are therefore formed in terms of the IED model of the respective charges, of zero rest masses, oscillating in either of the two unique vacuum potential fields, together with the radiation waves of their own charges. In this paper we give a first principles treatment of the dynamics of charge in a dielectric vacuum, based on which, combined with solutions for the radiation waves obtained previously, we subsequently derive the vacuum potential function for a given charge q, which we show to be quadratic and consist each of quantised potential levels, giving therefore rise to quantised characteristic oscillation frequencies of the charge and accordingly quantised, sharply-defined masses of the IED particles. By further combining with relevant experimental properties as input information, we determine the IED particles built from the charges +e,-e at their first excited states in the respective vacuum potential wells to be the proton and the electron, the observationally two only stable (permanently lived) and "free" particles containing one-unit charges. Their antiparticles as produced in pair productions can be accordingly determined. The characteristics of all of the other more energetic non-composite subatomic particles can also be recognised. We finally discuss the energy condition for pair production, which requires two successive energy supplies to (1) first disintegrate the bound pair of vaculeon charges +e,-e composing a vacuuon of the vacuum and (2) impart masses to the disintegrated charges.
Electron pair emission detected by time-of-flight spectrometers: Recent progress
Huth, Michael; Schumann, Frank O. [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Chiang, Cheng-Tien; Trtzschler, Andreas; Kirschner, Jrgen [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Institute of Physics, Martin-Luther-Universitt Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle (Saale) (Germany); Widdra, Wolf [Institute of Physics, Martin-Luther-Universitt Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle (Saale) (Germany); Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany)
2014-02-10T23:59:59.000Z
We present results for electron coincidence spectroscopy using two time-of-flight (ToF) spectrometers. Excited by electron impact, the energy and momentum distribution of electron pairs emitted from the Cu(111) surface are resolved and a spectral feature related to the Shockley surface state is identified. By combining the two ToF spectrometers with a high-order harmonic generation light source, we demonstrate double photoemission spectroscopy in the laboratory that required synchrotron radiation in the past. Utilizing this setup, we report results for (?,2e) on NiO(001) on Ag(001) excited with light at 30?eV photon energy.
Measurement of Delta G/G from high transverse momentum hadron pairs in COMPASS
Marcin Stolarski
2008-09-10T23:59:59.000Z
The new COMPASS Delta G/G result obtained from high transverse momentum hadron pairs in the Q^2>1 GeV^2 region is presented. Comparing to the previous analysis in this region the statistical error of Delta G/G is reduced by a factor 3 to 0.10. A weighted method of the Delta G/G measurement based on neural network approach is used. In addition, the formula for the Delta G/G extraction used in the analysis has been updated. The contributions coming from the leading order and QCD Compton processes are no longer neglected.
Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; Alverson, George O.; Alves, Gilvan Augusto; Aoki, Masato
2011-10-11T23:59:59.000Z
We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb^{-1} collected with the D0 detector at the Fermilab Tevatron Collider in pp? collisions at ?s = 1.96 TeV. In the channel LQLQ ? eq?_{e}q?, where q,q? are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and ?_{e}q?.
Quantum statistics effect in Schwinger pair production in short laser pulses
Florian Hebenstreit; Reinhard Alkofer; Gerald V. Dunne; Holger Gies
2009-10-23T23:59:59.000Z
We investigate non-perturbative pair production from vacuum (the Schwinger effect) in the focal region of two counter-propagating, ultra-short laser pulses with sub-cycle structure. We use the quantum kinetic formulation to calculate the momentum spectrum of created particles and show the extreme sensitivity to the laser frequency $\\omega$, the pulse length $\\tau$ and the carrier-envelope absolute phase $\\phi$. We apply this formalism to both fermions and bosons to illustrate the influence of quantum statistics in this type of electric background field.
Self-regulation of the reconnecting current layer in relativistic pair plasma reconnection
S. Zenitani; M. Hesse
2008-08-07T23:59:59.000Z
We investigate properties of the reconnecting current layer in relativistic pair plasma reconnection. We found that the current layer self-regulates its thickness when the current layer runs out current carriers, and so relativistic reconnection retains a fast reconnection rate. Constructing a steady state Sweet-Parker model, we discuss conditions for the current sheet expansion. Based on the energy argument, we conclude that the incompressible assumption is invalid in relativistic Sweet-Parker reconnection. The guide field cases are more incompressible than the anti-parallel cases, and we find a more significant current sheet expansion.
Temporal Loop Multiplexing: A resource efficient scheme for multiplexed photon-pair sources
Francis-Jones, Robert J A
2015-01-01T23:59:59.000Z
Single photons are a vital resource for photonic quantum information processing. However, even state-of-the-art single photon sources based on photon-pair generation and heralding detection have only a low probability of delivering a single photon when one is requested. We analyse a scheme that uses a switched fibre delay loop to increase the delivery probability per time bin of single photons from heralded sources. We show that, for realistic experimental parameters, combining the output of up to 15 pulses can yield a performance improvement of a factor of 10. We consider the future performance of this scheme with likely component improvements.
SUSY QCD Corrections to Higgs Pair Production from Bottom Quark Fusion
Sally Dawson; Chung Kao; Yili Wang
2007-10-23T23:59:59.000Z
We present a complete next-to-leading order (NLO) calculation for the total cross section for inclusive Higgs pair production via bottom-quark fusion at the CERN Large Hadron Collider (LHC) in the minimal supersymmetric standard model (MSSM) and the minimal supergravity model (mSUGRA). We emphasize the contributions of squark and gluino loops (SQCD) and the decoupling properties of our results for heavy squark and gluino masses. The enhanced couplings of the b quark to the Higgs bosons in supersymmetric models with large tanb yield large NLO SQCD corrections in some regions of parameter space.
Fermion Pair Production From an Electric Field Varying in Two Dimensions
J. E. Seger; A. B. Balantekin
1995-06-26T23:59:59.000Z
The Hamiltonian describing fermion pair production from an arbitrarily time-varying electric field in two dimensions is studied using a group-theoretic approach. We show that this Hamiltonian can be encompassed by two, commuting SU(2) algebras, and that the two-dimensional problem can therefore be reduced to two one-dimensional problems. We compare the group structure for the two-dimensional problem with that previously derived for the one-dimensional problem, and verify that the Schwinger result is obtained under the appropriate conditions.
On the Vlasov equation for Schwinger pair production in a time-dependent electric field
Adolfo Huet; Sang Pyo Kim; Christian Schubert
2015-01-26T23:59:59.000Z
Schwinger pair creation in a purely time-dependent electric field can be described through a quantum Vlasov equation describing the time evolution of the single-particle momentum distribution function. This equation exists in two versions, both of which can be derived by a Bogoliubov transformation, but whose equivalence is not obvious. For the spinless case, we show here that the difference between these two evolution equations corresponds to the one between the "in-out" and "in-in" formalisms. We give a simple relation between the asymptotic distribution functions generated by the two Vlasov equations. As examples we discuss the Sauter and single-soliton field cases.
Evidence for a Transverse Single-Spin Asymmetry in Leptoproduction of $\\pi^{+} \\pi^{-}$ Pairs
Airapetian, A; Akopov, Z; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bacchetta, A; Barion, L; Belostotskii, S; Bianchi, N; Blok, H P; Bttcher, H; Bonomo, C; Borisov, A; Borysenko, A; Brll, A; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Bryzgalov, V; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Devitsin, E; Diefenthaler, M; Di Nezza, P; Dreschler, J; Dren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Elalaoui-Moulay, A; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Funel, A; Gapienko, G; Gapienko, V; Garibaldi, F; Gavrilov, G; Karibian, V; Giordano, F; Grebenyuk, O; Gregor, I M; Griffioen, K; Guler, H; Hadjidakis, C; Hartig, M; Hasch, D; Hasegawa, T; Hesselink, W H A; Hill, G; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Hristova, I; Iarygin, G; Imazu, Y; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Keri, T; Kinney, E; Kiselev, A; Kobayashi, T; Kopytin, M; Korotkov, V; Kozlov, V; Krauss, B; Kravchenko, P; Krivokhizhin, V G; Lagamba, L; Lapiks, L; Lenisa, P; Linden-Levy, L A; Lorenzon, W; Lu, S; L, X; Ma, B Q; Liebing, P; Maiheu, B; Makins, N C R; Mao, Y; Marianski, B; Marukyan, H; Mexner, V; Miller, C A; Miyachi, Y; Muccifora, V; Murray, M; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Negodaev, M; Nowak, W D; Osborne, A; Pappalardo, L L; Perez-Benito, R; Pickert, N; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rock, S E; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Schfer, A; Schnell, G; Schler, K P; Seitz, B; Shearer, C; Shibata, T A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Streit, J; Tait, P; Taroian, S; Tchuiko, B; Terkulov, A; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Van Haarlem, Y; van Hulse, C; Veretennikov, D; Vikhrov, V; Vogel, C; Wang, S; Ye, Y; Ye, Z; Yen, S; Zeiler, D; Zihlmann, B; Zupranski, P
2008-01-01T23:59:59.000Z
A single-spin asymmetry was measured in the azimuthal distribution of $\\pi^{+} \\pi^{-}$ pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation between the transverse target polarization and the azimuthal orientation of the plane containing the two pions.The corresponding single-spin asymmetry is expected to be related to the product of the little-known quark transversity distribution function and an unknown naive-T-odd chiral-odd dihadron fragmentation function.
Neutron blocking and delayed proton pair alignment in superdeformed {sup 195}Pb
Farris, L.P.; Henry, E.A.; Becker, J.A.; Brinkman, M.J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Cederwall, B. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Cizewski, J.A. [Rutgers University, New Brunswick, New Jersey 08901 (United States)] [Rutgers University, New Brunswick, New Jersey 08901 (United States); Deleplanque, M.A.; Diamond, R.M. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Draper, J.E.; Duyar, C. [University of California, Davis, California 95616 (United States)] [University of California, Davis, California 95616 (United States); Fallon, P. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Hughes, J.R. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kelly, W.H. [Iowa State University, Ames, Iowa 50010 (United States)] [Iowa State University, Ames, Iowa 50010 (United States); Lee, I.Y.; Macchiavelli, A.O. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Rubel, E.C. [University of California, Davis, California 95616 (United States)] [University of California, Davis, California 95616 (United States); Stephens, F.S. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Vo, D.T. [Iowa State University, Ames, Iowa 50010 (United States)] [Iowa State University, Ames, Iowa 50010 (United States)
1995-05-01T23:59:59.000Z
Four new superdeformed bands have been observed in {sup 195}Pb, the first time superdeformation has been observed in an odd-{ital A} Pb nucleus. Two of the bands have a dynamic moment of inertia that is nearly constant as a function of {h_bar}{omega}. This is the first time that bands with such behavior have been observed in an odd-{ital A} nucleus in the {ital A}{approx}190 region and it is interpreted as the result of the blocking of the alignment of neutron pairs.
Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles
Gilbert, Benjamin
2008-10-01T23:59:59.000Z
The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; Alverson, George O.; Alves, Gilvan Augusto; Aoki, Masato
2011-10-11T23:59:59.000Z
We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider in pp? collisions at ?s = 1.96 TeV. In the channel LQLQ ? eq?eq?, where q,q? are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and ?eq?.
Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs
Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku , Saitama 338-8570 (Japan); Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Kuboya, Shigeyuki; Onabe, Kentaro [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Katayama, Ryuji [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
2013-12-04T23:59:59.000Z
We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.
A. Moujahid; A. D'Anjou; F. J. Torrealdea; C. Sarasola
2012-04-17T23:59:59.000Z
Many biological processes involve synchronization between nonequivalent systems, i.e, systems where the difference is limited to a rather small parameter mismatch. The maintenance of the synchronized regime in this cases is energetically costly \\cite{1}. This work studies the energy implications of synchronization phenomena in a pair of structurally flexible coupled neurons that interact through electrical coupling. We show that the forced synchronization between two nonidentical neurons creates appropriate conditions for an efficient actuation of adaptive laws able to make the neurons structurally approach their behaviours in order to decrease the flow of energy required to maintain the synchronization regime.
Moujahid, A; Torrealdea, F J; Sarasola, C; 10.1007/978-3-642-12433-4_77
2012-01-01T23:59:59.000Z
Many biological processes involve synchronization between nonequivalent systems, i.e, systems where the difference is limited to a rather small parameter mismatch. The maintenance of the synchronized regime in this cases is energetically costly \\cite{1}. This work studies the energy implications of synchronization phenomena in a pair of structurally flexible coupled neurons that interact through electrical coupling. We show that the forced synchronization between two nonidentical neurons creates appropriate conditions for an efficient actuation of adaptive laws able to make the neurons structurally approach their behaviours in order to decrease the flow of energy required to maintain the synchronization regime.
Christopher Thompson
2008-02-19T23:59:59.000Z
We consider the details of the QED processes that create electron-positron pairs in magnetic fields approaching and exceeding 10^{14} G. The formation of free and bound pairs is addressed, and the importance of positronium dissociation by thermal X-rays is noted. We calculate the collision cross section between an X-ray and a gamma ray, and point out a resonance in the cross section when the gamma ray is close to the threshold for pair conversion. We also discuss how the pair creation rate in the open-field circuit and the outer magnetosphere can be strongly enhanced by instabilities near the light cylinder. When the current has a strong fluctuating component, a cascade develops. We examine the details of particle heating, and show that a high rate of pair creation can be sustained close to the star, but only if the spin period is shorter than several seconds. The dissipation rate in this turbulent state can easily accommodate the observed radio output of the transient radio-emitting magnetars, and even their infrared emission. Finally, we outline how a very high rate of pair creation on the open magnetic field lines can help to stabilize a static twist in the closed magnetosphere and to regulate the loss of magnetic helicity by reconnection at the light cylinder.
Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Allgower, C.; Amonett, J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Caines, H.; Calderon de la Barca Sanchez, M.; Cardenas, A.; Carroll, J.; Castillo, J.; Castro, M.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Choi, B.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Corral, M.M.; Cramer, J.G.; Crawford, H.J.; Deng, W.S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Draper, J.E.; Dunin, V.B.; Dunlop, J.C.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Grachov, O.; Grigoriev, V.; Guedon, M.; Guertin, S.M.; Gushin, E.; Hallman, T.J.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Herston, T.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Humanic, T.J.; Igo, G.; Ishihara, A.; Ivanshin, Yu.I.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kaneta, M.; Kaplan, M.; Keane, D.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Kollegger, T.; Konstantinov, A.; Kopytine, S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.K.; Kuznetsov, A.A.; Lamont, M.A.C.; Landgraf, J.M.; Lange, S.; Lansdell, C.P.; Lasiuk, B.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Leontiev, V.M.; LeVine, M.J.; Li, Q.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, L.; Liu, Z.; et al.
2004-04-07T23:59:59.000Z
We present the first data on e{sup +}e{sup -} pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, p{sub T}, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The e{sup +} and e{sup -} p{sub T} spectra are similar, with no evidence for interference effects due to higher-order diagrams.
Electrostatic soliton and double layer structures in unmagnetized degenerate pair plasmas
Mahmood, S. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics (DPAM), PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan); Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad 44000 (Pakistan); Ur-Rehman, H. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics (DPAM), PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan)
2010-11-15T23:59:59.000Z
The acoustic solitons and double layers are studied in unmagnetized quantum electron-positron plasmas in the presence of stationary ions. The quantum hydrodynamic model is employed and reductive perturbation method is used to derive the Korteweg-de Vries (KdV) and extended KdV equations for solitons and double layers, respectively. It is found that in the linear limit both slow acoustic and fast Langmuir waves can propagate in such type of quantum plasmas like in classical pair-ion or pair plasmas. The amplitude and width of the electrostatic solitons are found to be decreasing with the increase in concentration of positrons (or decrease in the concentration of ions) in degenerate electron-positron-ion plasmas. It is found that only rarefactive double layer can exist in such plasmas which depend on various parameters. The dependence of double layer structure on ion concentration and quantum diffraction effects of electrons and positrons are also discussed. The results are also elaborated graphically by considering dense plasma parameters in the outer layers of astrophysical objects such as white dwarfs and neutron stars.
Compass Results on Gluon Polarisation from High pT hadron pairs
L. Silva; for the COMPASS Collaboration
2010-10-13T23:59:59.000Z
One of the goals of the COMPASS experiment is the determination of the gluon polarisation \\Delta G/G, for a deep understanding of the spin structure of the nucleon. In DIS the gluon polarisation can be measured via the Photon-Gluon-Fusion (PGF) process, identified by open charm production or by selecting high p_T hadron pairs in the final state. The data used for this work were collected by the COMPASS experiment during the years 2002-2004, using a 160 GeV naturally polarised positive muon beam scattering on a polarised nucleon target. A new preliminary result of the gluon polarisation \\Delta G/G from high p_T hadron pairs in events with Q^2>1 (GeV/c)^2 is presented. In order to extract \\Delta G/G, this analysis takes into account the leading process \\gamma q contribution together with the PGF and QCD Compton processes. A new weighted method based on a neural network approach is used. A preliminary \\Delta G/G result for events from quasi-real photoproduction (Q^2<1 (GeV/c)^2) is also presented.
Non-resonant kaon pair production and medium effects in proton-nucleus collisions
E. Ya. Paryev; M. Hartmann; Yu. T. Kiselev
2015-05-08T23:59:59.000Z
We study the non-resonant (non-$\\phi$) production of $K^+K^-$ pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag, and Au targets within the collision model, based on the nuclear spectral function, for incoherent primary proton--nucleon and secondary pion--nucleon creation processes. The model takes into account the initial proton and final kaon absorption, target nucleon binding and Fermi motion as well as nuclear mean-field potential effects on these processes. We calculate the antikaon momentum dependences of the exclusive absolute and relative $K^+K^-$ pair yields in the acceptance window of the ANKE magnetic spectrometer, used in a recent experiment performed at COSY, within the different scenarios for the antikaon-nucleus optical potential. We demonstrate that the above observables are strongly sensitive to this potential. Therefore, they can be useful to help determine the $K^-$ optical potential from the direct comparison of the results of our calculations with the data from the respective ANKE-at-COSY experiment. We also show that the pion--nucleon production channels dominate in the low-momentum $K^-$, $K^+$ production in the considered kinematics and, hence, they have to be accounted for in the analysis of these data.
Development of Hard X-ray Imaging Optics with Two Pairs of Elliptical and Hyperbolic Mirrors
Matsuyama, S.; Fujii, M.; Wakioka, T.; Mimura, H.; Handa, S.; Kimura, T. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishino, Y.; Tamasaku, K.; Makina, Y.; Ishikawa, T. [SPring-8/RIKEN, 1-1-1 Kouto, Sayoucho, Sayogun, Hyogo 679-5148 (Japan); Yamauchi, K. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Research Center for Ultra-Precision Science and Technology, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)
2010-06-23T23:59:59.000Z
To form a magnified hard X-ray image with a 50 nm resolution, we have studied total reflection mirror optics with two pairs of elliptical and hyperbolic mirrors, which is called 'Advanced Kirkpatrick-Baez system'. A designed optical system has 200x and 300x magnifications in vertical and horizontal directions. Also diffraction limit size in the optical system is 40 nmx45 nm. We fabricated a pair of elliptical and hyperbolic mirrors for horizontal imaging with a figure accuracy of 2 nm using elastic emission machining (EEM), microstitching interferometry (MSI) and relative-angle-determinable stitching interferometry (RADSI). One-dimensional tests for forming a demagnified image of a slit were carried out at an X-ray energy of 11.5 keV at BL29XUL (EH2) of SPring-8. As a result, a shape beam with a FWHM of 78 nm was observed. This demonstrates that we realized one-dimensional Wolter optics that has a spatial resolution of 78 nm.
Signature of heavy Majorana neutrinos at a linear collider: Enhanced charged Higgs pair production
Atwood, David [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Bar-Shalom, Shaouly [Physics Department, Technion-Institute of Technology, Haifa 32000 (Israel); Soni, Amarjit [Theory Group, Brookhaven National Laboratory, Upton, New York 11973 (United States)
2007-08-01T23:59:59.000Z
A charged Higgs pair can be produced at an ee collider through a t-channel exchange of a heavy neutrino (N) via e{sup +}e{sup -}{yields}H{sup +}H{sup -} and, if N is a Majorana particle, also via the lepton number violating (LNV) like-sign reaction e{sup {+-}}e{sup {+-}}{yields}H{sup {+-}}H{sup {+-}}. Assuming no a priori relation between the effective eNH{sup +} coupling ({xi}) and light neutrino masses, we show that this interaction vertex can give a striking enhancement to these charged Higgs pair production processes. In particular, the LNV H{sup -}H{sup -} signal can probe N at the International Linear Collider (ILC) in the mass range 100 GeV < or approx. m{sub N} < or approx. 10{sup 4} TeV and with the effective mixing angle {xi} in the range 10{sup -4} < or approx. {xi}{sup 2} < or approx. 10{sup -8}--well within its perturbative unitarity bound and the {beta}{beta}{sub 0{nu}} limit. The lepton number conserving e{sup +}e{sup -}{yields}H{sup +}H{sup -} mode can be sensitive to, e.g., an O(10) TeV heavy Majorana neutrino at a 500 GeV ILC, if {xi}{sup 2} > or approx. 0.001.
Interstellar Hydroxyl Masers in the Galaxy. II. Zeeman Pairs and the Galactic Magnetic Field
Vincent L. Fish; Mark J. Reid; Alice L. Argon; Karl M. Menten
2003-07-08T23:59:59.000Z
We have identified and classified Zeeman pairs in the survey by Argon, Reid, & Menten of massive star-forming regions with 18 cm (2 Pi 3/2, J = 3/2) OH maser emission. We have found a total of more than 100 Zeeman pairs in more than 50 massive star-forming regions. The magnetic field deduced from the Zeeman splitting has allowed us to assign an overall line-of-sight magnetic field direction to many of the massive star-forming regions. Combining these data with other data sets obtained from OH Zeeman splitting, we have looked for correlations of magnetic field directions between star-forming regions scattered throughout the Galaxy. Our data do not support a uniform, Galactic-scale field direction, nor do we find any strong evidence of magnetic field correlations within spiral arms. However, our data suggest that in the Solar neighborhood the magnetic field outside the Solar circle is oriented clockwise as viewed from the North Galactic Pole, while inside the Solar circle it is oriented counterclockwise. This pattern, including the magnetic field reversal near the Sun, is in agreement with results obtained from pulsar rotation measures.
Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions
Khachatryan, V. [Yerevan Physics Institute (Armenia); et al.,
2014-10-01T23:59:59.000Z
A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 24.6 fb$^{?1}$, with 4.9 fb$^{?1}$ at 7 TeV and 19.7 fb$^{?1}$ at 8 TeV. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes the case where the Higgs boson is produced in association with a b-quark jet. No excess is observed in the tau-lepton-pair invariant mass spectrum. Exclusion limits are presented in the MSSM parameter space for different benchmark scenarios, m$_{h}^{max}$ , m$_{h}^{mod?+}$ , m$_{h}^{mod??}$ , light-stop, light-stau, ?-phobic, and low-m$_{H}$. Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given.
The curious case of HD41248. A pair of static signals buried behind red-noise
Jenkins, James S
2014-01-01T23:59:59.000Z
Gaining a better understanding of the effects of stellar induced radial velocity noise is critical for the future of exoplanet studies, since the discovery of the lowest-mass planets using this method will require us to go below the intrinsic stellar noise limit. An interesting test case in this respect is that of the southern solar analogue HD41248. The radial velocity time series of this star has been proposed to contain either a pair of signals with periods of around 18 and 25 days, that could be due to a pair of resonant super-Earths, or a single and varying 25 day signal that could arise due to a complex interplay between differential rotation and modulated activity. In this letter we build-up more evidence for the former scenario, showing that the signals are still clearly significant even after more than 10 years of observations and they likely do not change in period, amplitude, or phase as a function of time, the hallmarks of static Doppler signals. We show that over the last two observing seasons th...
Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP
Schael, S; Bruneliere, R; Buskulic, D; De Bonis, I; Decamp, D; Ghez, P; Goy, C; Jezequel, S; Lees, J P; Lucotte, A; Martin, F; Merle, E; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Trocme, B; Bravo, S; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Fernandez, E; Fernandez-Bosman, M; Garrido, Ll; Grauges, E; Juste, A; Martinez, M; Merino, G; Miquel, R; Mir, Ll. M; Orteu, S; Pacheco, A; Park, I C; Perlas, J; Riu, I; Ruiz, H; Sanchez, F; Colaleo, A; Creanza, D; De Filippis, N; De Palma, M; Iaselli, G; Maggi, G; Maggi, M; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Bazarko, A; Becker, U; Boix, G; Bird, F; Blucher, E; Bonvicini, B; Bright-Thomas, P; Barklow, T; Buchmuller, O; Cattaneo, M; Cerutti, F; Ciulli, V; Clerbaux, B; Drevermann, H; Forty, R W; Frank, M; Greening, T C; Hagelberg, R; Halley, A W; Gianotti, F; Girone, M; Hansen, J B; Harvey, J; Jacobsen, R; Hutchcroft, D E; Janot, P; Jost, B; Knobloch, J; Kado, M; Lehraus, I; Lazeyras, P; Maley, P; Mato, P; May, J; Moutoussi, A; Pepe-Altarelli, M; Ranjard, F; Rolandi, L; Schlatter, D; Schmitt, B; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Tournefier, E; Veenhof, R; Valassi, A; Wiedenmann, W; Wright, A E; Ajaltouni, Z; Badaud, F; Chazelle, G; Deschamps, O; Dessagne, S; Falvard, A; Ferdi, C; Fayolle, D; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Pascolo, J M; Perret, P; Podlyski, F; Bertelsen, H; Fernley, T; Hansen, J D; Hansen, J R; Hansen, P H; Kraan, A C; Lindahl, A; Mollerud, R; Nilsson, B S; Rensch, B; Waananen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, E; Siotis, I; Vayaki, A; Zachariadou, K; Blondel, A; Bonneaud, G; Brient, J C; Machefert, F; Rouge, A; Rumpf, M; Swynghedauw, M; Tanaka, R; Verderi, M; Videau, H; Ciulli, V; Focardi, E; Parrini, G; Zachariadou, K; Corden, M; Georgiopoulos, C; Antonelli, A; Antonelli, M; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Cerutti, F; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, G P; Passalacqua, L; Picchi, P; Colrain, P; Have, I. ten; Hughes, I S; Kennedy, J; Knowles, I G; Lynch, J G; Morton, W T; Negus, P; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Turnbull, R M; Wasserbaech, S; Buchmuller, O; Cavanaugh, R; Dhamotharan, S; Geweniger, C; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Stenzel, H; Tittel, K; Werner, W; Wunsch, M; Beuselinck, R; Binnie, D M; Cameron, W; Davies, G; Dornan, P J; Goodsir, S; Marinelli, N; Martin, E B; Nash, J; Nowell, J; Rutherford, S A; Sedgbeer, J K; Thompson, J C; White, R; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Bouhova-Thacker, E; Bowdery, C K; Buck, P G; Clarke, D P; Ellis, G; Finch, A J; Foster, F; Hughes, G; Jones, R.W L; Keemer, N R; Pearson, M R; Robertson, N A; Sloan, T; Smizanska, M; Snow, S W; Williams, M I; van der Aa, O; Delaere, C; Leibenguth, G; Lemaitre, V; Bauerdick, L.A T; Blumenschein, U; van Gemmeren, P; Giehl, I; Holldorfer, F; Jakobs, K; Kasemann, M; Kayser, F; Kleinknecht, K; Muller, A S; Quast, G; Renk, B; Rohne, E; Sander, H G; Schmeling, S; Wachsmuth, H; Wanke, R; Zeitnitz, C; Ziegler, T; Aubert, J J; Benchouk, C; Bonissent, A; Carr, J; Coyle, P; Curtil, C; Ealet, A; Etienne, F; Fouchez, D; Motsch, F; Payre, P; Rousseau, D; Tilquin, A; Talby, M; Thulasidas, M; Aleppo, M; Antonelli, M; Ragusa, F; Buscher, V; David, A; Dietl, H; Ganis, G; Huttmann, K; Lutjens, G; Mannert, C; Manner, W; Moser, H G; Settles, R; Seywerd, H; Stenzel, H; Villegas, M; Wiedenmann, W; Wolf, G; Azzurri, P; Boucrot, J; Callot, O; Chen, S; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, Ph; Jacholkowska, A; Le Diberder, F; Lefrancois, J; Mutz, A M; Schune, M H; Serin, L; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Bettarini, S; Boccali, T; Bozzi, C; Calderini, G; Dell'Orso, R; Fantechi, R; Ferrante, I; Fidecaro, F; Foa, L; Giammanco, A; Giassi, A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, F; Rizzo, G; Sanguinetti, G; Sciaba, A; Sguazzoni, G; Spagnolo, P; Steinberger, J; Tenchini, R; Vannini, C; Venturi, A; Verdini, P G; Awunor, O; Blair, G A; Cowan, G; Garcia-Bellido, A; Green, M G; Medcalf, T; Misiejuk, A; Strong, J A; Teixeira-Dias, P; Botterill, D R; Clifft, R W; Edgecock, T R; Edwards, M; Haywood, S J; Norton, P R; Tomalin, I R; Ward, J J; Bloch-Devaux, B; Boumediene, D; Colas, P; Emery, S; Fabbro, B; Kozanecki, W; Lancon, E; Lemaire, M C; Locci, E; Perez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Tuchming, B; Vallage, B; Black, S N; Dann, J H; Kim, H Y; Konstantinidis, N; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Cartwright, S
2013-01-01T23:59:59.000Z
Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising ...
Search for Resonances in the Photoproduction of Proton-Antiproton Pairs
Burnham Stokes
2006-06-30T23:59:59.000Z
Results are reported on the reaction {gamma}p {yields} p{bar p}p with beam energy in the range 4.8-5.5 GeV. The data were collected at the Thomas Jefferson National Accelerator Facility in CLAS experiment E01-017(G6C). The focus of this study is an understanding of the mechanisms of photoproduction of proton-antiproton pairs, and to search for intermediate resonances, both narrow and broad, which decay to p{bar p}. The total measured cross section in the photon energy range 4.8-5.5 GeV is {sigma} = 33 {+-} 2 nb. Measurement of the cross section as a function of energy is provided. An upper limit on the production of a narrow resonance state previously observed with a mass of 2.02 GeV/c{sup 2} is placed at 0.35 nb. No intermediate resonance states were observed. Meson exchange production appears to dominate the production of the proton-antiproton pairs.
Johnson, John Asher [California Institute of Technology, Department of Astrophysics, MC 249-17, Pasadena, CA 91125 (United States); Payne, Matthew; Ford, Eric B. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611-2055 (United States); Howard, Andrew W.; Marcy, Geoffrey W. [Department of Astronomy, University of California, Mail Code 3411, Berkeley, CA 94720 (United States); Clubb, Kelsey I. [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States); Bowler, Brendan P. [Institute for Astronomy, University of Hawai'i, Honolulu, HI 96822 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Boulevard, Box 9501, Nashville, TN 37209 (United States); Fischer, Debra A.; Brewer, John M.; Schwab, Christian [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Reffert, Sabine [ZAH-Landessternwarte, Koenigstuhl 12, D-69117 Heidelberg (Germany); Lowe, Thomas B., E-mail: johnjohn@astro.caltech.edu [UCO/Lick Observatory, Santa Cruz, CA 95064 (United States)
2011-01-15T23:59:59.000Z
We report radial velocity (RV) measurements of the G-type subgiants 24 Sextanis (= HD 90043) and HD 200964. Both are massive, evolved stars that exhibit periodic variations due to the presence of a pair of Jovian planets. Photometric monitoring with the T12 0.80 m APT at Fairborn Observatory demonstrates both stars to be constant in brightness to {<=}0.002 mag, thus strengthening the planetary interpretation of the RV variations. Based on our dynamical analysis of the RV time series, 24 Sex b, c have orbital periods of 452.8 days and 883.0 days, corresponding to semimajor axes 1.333 AU and 2.08 AU, and minimum masses 1.99 M{sub Jup} and 0.86 M{sub Jup}, assuming a stellar mass M{sub *}= 1.54 M{sub sun}. HD 200964 b, c have orbital periods of 613.8 days and 825.0 days, corresponding to semimajor axes 1.601 AU and 1.95 AU, and minimum masses 1.99 M{sub Jup} and 0.90 M{sub Jup}, assuming M{sub *}= 1.44 M{sub sun}. We also carry out dynamical simulations to properly account for gravitational interactions between the planets. Most, if not all, of the dynamically stable solutions include crossing orbits, suggesting that each system is locked in a mean-motion resonance that prevents close encounters and provides long-term stability. The planets in the 24 Sex system likely have a period ratio near 2:1, while the HD 200964 system is even more tightly packed with a period ratio close to 4:3. However, we caution that further RV observations and more detailed dynamical modeling will be required to provide definitive and unique orbital solutions for both cases, and to determine whether the two systems are truly resonant.
Hard photo-disintegration of proton pairs in {sup 3}He nuclei
Ishay Pomerantz
2011-09-01T23:59:59.000Z
Extensive studies of high-energy deuteron photodisintegration over the past two decades have probed the limits of meson-baryon descriptions of nuclei and nuclear reactions. At high energies, photodisintegration cross sections have been shown to scale as a power law in s (the total cm energy squared), which suggests that quarks are the relevant degrees of freedom. In an attempt to more clearly identify the underlying dynamics at play, JLab/Hall A experiment 03-101 measured the hard photodisintegration of {sup 3}He into p-p and p-d pairs at ?{sub c.m.} = 90? and E{sub {gamma}} = 0.8 - 4.7 GeV. The basic idea is that the measurement should be able to test theoretical predictions for the relative size of pp versus pn disintegrations. This document presents data for the energy dependence of the high energy 90? c.m. photodisintegration of {sup3]He: d?/dt(? + {sup3}He ? p + p + n{sub spectator}), and d?/dt(? + {sup 3}He ? p + d). The cross sections were observed to scale as a function of s{sup ?n} where n was found to be 11.10.1 and 17.40.5 for the two reactions respectively. The degree of scaling found for d#27;{sigma}/dt (? + {sup 3}He ? p + d) is the highest degree of scaling ever observed in a nuclear process. The onset of the observed scaling are at photon energy of 2.2 GeV for the pp breakup and 0.7 GeV for the pd breakup. The magnitude of the invariant cross section for pp pair breakup was found to be dramatically lower than for the breakup of pn pairs and theoretical predictions. At energies below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in the pn breakup. The data indicate a transition from three-nucleon hadronic photodisintegration processes at low energies to two-nucleon quark-dominated photodisintegration processes at high energies.
Biggs, D.C. [Texas A& M Univ., College Station, TX (United States)] [Texas A& M Univ., College Station, TX (United States); Mueller-Karger, F.E. [Univ. of South Florida, St. Petersburg, FL (United States)] [Univ. of South Florida, St. Petersburg, FL (United States)
1994-04-15T23:59:59.000Z
When anticyclonic eddies shed by the Loop Current of the Gulf of Mexico reach the western margin of the gulf, they influence the surface circulation over the continental slope and rise. Of particular interest is the generation of cyclone (cold-core)- anticyclone (warm-core) pairs when aging Loop Current eddies interact with the continental margin. In this paper the authors describe the physical and biological characteristics of these cyclone-anticyclone pairs. Their objective was to determine how eddy pairs affect the distribution of phytoplankton in the region and how satellite ocean color measurements are applicable to tracing of the eddies. They present shipboard data collected between 1980 and 1982 on the hydrography, chlorophyll stocks, and nutrient concentrations of eddy pairs in the western Gulf of Mexico and compare these data with coastal zone color scanner (CZCS) images collected during the time frame of the cruises. Surface pigment concentrations followed a seasonal cycle, with low concentrations (0.05-0.1 mg m{sup {minus}3}) found within cyclones and anticyclones from April through early November and higher concentrations (>0.1 mg m{sup {minus}3}) found in the winter. CZCS pigment concentrations were locally high in the flow confluence of cyclone-anticyclone pairs. The CZCS imagery shows that some cyclone-anticyclone geometries transport high-chlorophyll shelf water seaward at least 100-200 km off-shelf. 46 figs., 9 figs., 3 tabs.
Shota Kino; Taiki Nii; Holger F. Hofmann
2015-02-23T23:59:59.000Z
Joint measurements of non-commuting observables are characterized by unavoidable measurement uncertainties that can be described in terms of the error statistics for input states with well-defined values for the target observables. However, a complete characterization of measurement errors must include the correlations between the errors of the two observables. Here, we show that these correlations appear in the experimentally observable measurement statistics obtained by performing the joint measurement on maximally entangled pairs. For two-level systems, the results indicate that quantum theory requires imaginary correlations between the measurement errors of X and Y since these correlations are represented by the operator product XY=iZ in the measurement operators. Our analysis thus reveals a directly observable consequence of non-commutativity in the statistics of quantum measurements.
Alejandro Carrillo; Marcio F. Cornelio; Marcos C. de Oliveira
2013-04-10T23:59:59.000Z
Earth's magnetic field is essential for orientation in birds migration. The most promising explanation for this orientation is the photo-stimulated radical pair (RP) mechanism, conjectured to occur in cryptochrome photoreceptors. The radicals must have an intrinsic anisotropy in order to define a reference frame for the compass. This anisotropy, when introduced through hyperfine interactions, imposes immobility of the RP, and implies that entanglement between the unpaired electrons of the RP is preserved over long coherence times. We show that this kind of anisotropy, and consequently the entanglement in the model, are not necessary for the proper functioning of the compass. Classically correlated initial conditions for the RP, subjected to a fast decoherence process, are able to provide the anisotropy required. The environment in which the RP is immersed is then responsible for the reference frame of the compass, relaxing the immobility assumption. This fact significantly expands the range of applicability of the RP mechanism providing more elements for experimental search.
D'Angelo, M; Sgattoni, A; Pegoraro, F; Macchi, A
2015-01-01T23:59:59.000Z
The evolution of the filamentation instability produced by two counter-streaming pair plasmas is studied with particle-in-cell (PIC) simulations in both one (1D) and two (2D) spatial dimensions. Radiation friction effects on particles are taken into account. After an exponential growth of both the magnetic field and the current density, a nonlinear quasi-stationary phase sets up characterized by filaments of opposite currents. During the nonlinear stage, a strong broadening of the particle energy spectrum occurs accompanied by the formation of a peak at twice their initial energy. A simple theory of the peak formation is presented. The presence of radiative losses does not change the dynamics of the instability but affects the structure of the particle spectra.
Search for the associated production of the Higgs boson with a top-quark pair
Khachatryan, Vardan [Yerevan Physics Institute (Armenia)
2014-09-01T23:59:59.000Z
A search for the standard model Higgs boson produced in association with a top-quark pair (t?tH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb? and 19.7 fb? collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H ? hadrons, H ? photons, and H ? leptons. The results are characterized by an observed t?tH signal strength relative to the standard model cross section, ?=?/?_{SM}, under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is ? = 2.8 1.0 for a Higgs boson mass of 125.6 GeV.
Search for the associated production of the Higgs boson with a top-quark pair
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan
2014-09-01T23:59:59.000Z
A search for the standard model Higgs boson produced in association with a top-quark pair (t?tH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb? and 19.7 fb? collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H ? hadrons, H ? photons, and H ? leptons. The results are characterized by an observed t?tH signal strength relative to the standard model cross section, ?=?/?SM, under the assumption that the Higgs boson decays as expected in themorestandard model. The best fit value is ? = 2.8 1.0 for a Higgs boson mass of 125.6 GeV.less
Search for the associated production of the Higgs boson with a top-quark pair
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan [Yerevan Physics Institute (Armenia)
2014-09-01T23:59:59.000Z
A search for the standard model Higgs boson produced in association with a top-quark pair (t?tH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb? and 19.7 fb? collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H ? hadrons, H ? photons, and H ? leptons. The results are characterized by an observed t?tH signal strength relative to the standard model cross section, ?=?/?SM, under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is ? = 2.8 1.0 for a Higgs boson mass of 125.6 GeV.
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.
Pair of null gravitating shells II. Canonical theory and embedding variables
P. Hajicek; I. Kouletsis
2001-12-28T23:59:59.000Z
The study of the two shell system started in our first paper ``Pair of null gravitating shells I'' (gr-qc/0112060) is continued. An action functional for a single shell due to Louko, Whiting and Friedman is generalized to give appropriate equations of motion for two and, in fact, any number of spherically symmetric null shells, including the cases when the shells intersect. In order to find the symplectic structure for the space of solutions described in paper I, the pull back to the constraint surface of the Liouville form determined by the action is transformed into new variables. They consist of Dirac observables, embeddings and embedding momenta (the so-called Kucha\\v{r} decomposition). The calculation includes the integration of a set of coupled partial differential equations. A general method of solving the equations is worked out.
Quantum Simulation of Pairing Hamiltonians with Nearest-Neighbor Interacting Qubits
Zhixin Wang; Xiu Gu; Lian-Ao Wu; Yu-xi Liu
2014-11-23T23:59:59.000Z
Although a universal quantum computer is still far from reach, the tremendous advances in controllable quantum devices, in particular with solid-state systems, make it possible to physically implement "quantum simulators". Quantum simulators are physical setups able to simulate other quantum systems efficiently that are intractable on classical computers. Based on solid-state qubit systems with various types of nearest-neighbor interactions, we propose a complete set of algorithms for simulating pairing Hamiltonians. Fidelity of the target states corresponding to each algorithm is numerically studied. We also compare algorithms designed for different types of experimentally available Hamiltonians and analyze their complexity. Furthermore, we design a measurement scheme to extract energy spectra from the simulators. Our simulation algorithms might be feasible with state-of-the-art technology in solid-state quantum devices.
Coulomb displacement energies as a probe for nucleon pairing in the $f_{7/2}$ shell
A. Kankainen; T. Eronen; D. Gorelov; J. Hakala; A. Jokinen; V. S. Kolhinen; M. Reponen; J. Rissanen; A. Saastamoinen; V. Sonnenschein; J. yst
2014-03-17T23:59:59.000Z
Coulomb displacement energies of $T=1/2$ mirror nuclei have been studied via a series of high-precision $Q_\\mathrm{EC}$-value measurements with the double Penning trap mass spectrometer JYFLTRAP. Most recently, the $Q_\\mathrm{EC}$ values of the $f_{7/2}$-shell mirror nuclei $^{45}$V ($Q_\\mathrm{EC}=7123.82(22)$ keV) and $^{49}$Mn ($Q_\\mathrm{EC}=7712.42(24)$ keV) have been measured with an unprecedented precision. The data reveal a 16-keV ($1.6\\sigma$) offset in the adopted Atomic Mass Evaluation 2012 value of $^{49}$Mn suggesting the need for further measurements to verify the breakdown of the quadratic form of the isobaric multiplet mass equation. Precisely measured $Q_\\mathrm{EC}$ values confirm that the pairing effect in the Coulomb energies is quenched when entering the $f_{7/2}$ shell and reaches a minimum in the midshell.
Neutrino-Pair Emission due to Electron-Phonon Scattering in a Neutron Star Crust
D. G. Yakovlev; A. D. Kaminker
1996-04-19T23:59:59.000Z
Neutrino-pair bremsstrahlung radiation is considered due to electron--phonon scattering of degenerate, relativistic electrons in a lattice of spherical atomic nuclei in a neutron star crust. The neutrino energy generation rate is calculated taking into account exact spectrum of phonons, the Debye--Waller factor, and the nuclear form--factor in the density range from $10^7$~g~cm$^{-3}$ to $10^{14}$~g~cm$^{-3}$ at arbitrary nuclear composition for body-centered-cubic and face-centered-cubic Coulomb crystals. The results are fitted by a unified analytic expression. A comparison is given of the neutrino bremsstrahlung energy losses in a neutron star crust composed of ground state and accreted matter, in the solid and liquid phases.
Synthetic Diamond and Wurtzite Structures Self-Assemble with Isotropic Pair Interactions
Mikael C. Rechtsman; Frank H. Stillinger; Salvatore Torquato
2007-09-24T23:59:59.000Z
Using inverse statistical-mechanical optimization techniques, we have discovered isotropic pair interaction potentials with strongly repulsive cores that cause the tetrahedrally coordinated diamond and wurtzite lattices to stabilize, as evidenced by lattice sums, phonon spectra, positive-energy defects, and self-assembly in classical molecular dynamics simulations. These results challenge conventional thinking that such open lattices can only be created via directional covalent interactions observed in nature. Thus, our discovery adds to fundamental understanding of the nature of the solid state by showing that isotropic interactions enable the self-assembly of open crystal structures with a broader range of coordination number than previously thought. Our work is important technologically because of its direct relevance generally to the science of self-assembly and specifically to photonic crystal fabrication.
Integrable Gross-Neveu models with fermion-fermion and fermion-antifermion pairing
Michael Thies
2014-08-23T23:59:59.000Z
The massless Gross-Neveu and chiral Gross-Neveu models are well known examples of integrable quantum field theories in 1+1 dimensions. We address the question whether integrability is preserved if one either replaces the four-fermion interaction in fermion-antifermion channels by a dual interaction in fermion-fermion channels, or if one adds such a dual interaction to an existing integrable model. The relativistic Hartree-Fock-Bogoliubov approach is adequate to deal with the large N limit of such models. In this way, we construct and solve three integrable models with Cooper pairing. We also identify a candidate for a fourth integrable model with maximal kinematic symmetry, the "perfect" Gross-Neveu model. This type of field theories can serve as exactly solvable toy models for color superconductivity in quantum chromodynamics.
Top pair production at a future $e^+e^-$ machine in a composite Higgs scenario
Daniele Barducci; Stefania De Curtis; Stefano Moretti; Giovanni Marco Pruna
2015-04-21T23:59:59.000Z
The top quark plays a central role in many New Physics scenarios and in understanding the details of Electro-Weak Symmetry Breaking. In the short- and mid-term future, top-quark studies will mainly be driven by the experiments at the Large Hadron Collider. Exploration of top quarks will, however, be an integral part of particle physics studies at any future facility and an $e^+ e^-$ collider will have a very comprehensive top-quark physics program. We discuss the possibilities of testing NP in the top-quark sector within a composite Higgs scenario through deviations from the Standard Model in top pair production for different Centre-of-Mass energy options of a future $e^+e^-$ machine. In particular, we focus on precision studies of the top-quark sector at a CM energy ranging from 370 GeV up to 3 TeV.
Search for pair production of the scalar top quark in the electron+muon final state
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Alexeev, G.D.; Alkhazov, G.; Altona, A.; Alverson, G.; Alves, G.A.
2010-09-01T23:59:59.000Z
We report the result of a search for the pair production of the lightest supersymmetric partner of the top quark ({tilde t}{sub 1}) in p{bar p} collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider corresponding to an integrated luminosity of 5.4 fb{sup -1}. The scalar top quarks are assumed to decay into a b quark, a charged lepton, and a scalar neutrino ({tilde {nu}}), and the search is performed in the electron plus muon final state. No significant excess of events above the standard model prediction is detected, and improved exclusion limits at the 95% C.L. are set in the (M{sub {tilde t}{sub 1}}, M{sub {tilde {nu}}}) mass plane.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gorelik, Tatiana E.; Billinge, Simon J. L.; Schmidt, Martin U.; Kolb, Ute
2015-04-01T23:59:59.000Z
This paper shows for the first time that pair-distribution function analyses can be carried out on organic and organo-metallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction (SAED) and nanodiffraction in transmission electron microscopy (TEM) or nanodiffraction in scanning transmission electron microscopy (STEM) modes. The methods were demonstrated on organo-metallic complexes (chlorinated and unchlorinated copper-phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrating that the problems of obtaining kinematical scattering datamoreand avoiding beam-damage of the sample are possible to resolve.less
Search for Light Resonances Decaying into Pairs of Muons as a Signal of New Physics
Chatrchyan, S. [Yerevan Physics Institute(Armenia)
2011-07-01T23:59:59.000Z
A search for groups of collimated muons is performed using a data sample collected by the CMS experiment at the LHC, at a centre-of-mass energy of 7 TeV, and corresponding to an integrated luminosity of 35 inverse picobarns. The analysis searches for production of new low-mass states decaying into pairs of muons and is designed to achieve high sensitivity to a broad range of models predicting leptonic jet signatures. With no excess observed over the background expectation, upper limits on the production cross section times branching fraction times acceptance are set, ranging from 0.1 to 0.5 pb at the 95% CL depending on event topology. In addition, the results are interpreted in several benchmark models in the context of supersymmetry with a new light dark sector exploring previously inaccessible parameter space.
Orbital dependent nucleonic pairing in the lightest known isotopes of tin
Iain G. Darby; Robert K. Grzywacz; Jon C. Batchelder; Carrol R. Bingham; Lucia Cartegni; Carl J. Gross; Morten Hjorth-Jensen; David T. Joss; Sean N. Liddick; Witold Nazarewicz; Stephen Padgett; Robert D. Page; Thomas Papenbrock; Mustafa M. Rajabali; Jimmy Rotureau; Krzysztof P. Rykaczewski
2010-09-11T23:59:59.000Z
By studying the 109Xe-->105Te-->101Sn superallowed alpha-decay chain, we observe low-lying states in 101Sn, the one-neutron system outside doubly magic 100Sn. We find that the spins of the ground state (J = 7=2) and first excited state (J = 5=2) in 101Sn are reversed with respect to the traditional level ordering postulated for 103Sn and the heavier tin isotopes. Through simple arguments and state-of-the-art shell model calculations we explain this unexpected switch in terms of a transition from the single-particle regime to the collective mode in which orbital-dependent pairing correlations, dominate.
CP violation and electric-dipole-moment at low energy tau-pair production
J. Bernabeu; G. A. Gonzalez-Sprinberg; J. Vidal
2004-10-11T23:59:59.000Z
CP violation at low energy is investigated at the tau electromagnetic vertex. High statistics at B factories, and on top of the Upsilon resonances, allows a detailed investigation of CP-odd observables related to the tau-pair production. The contribution of the tau electric dipole moment is considered in detail. We perform an analysis independent from the high energy data by means of correlation and linear spin observables at low energy. We show that different CP-odd asymmetries, associated to the normal-transverse and normal-longitudinal correlation terms can be measured at low energy accelerators, both at resonant and non resonant energies. These observables allow to put stringent and independent bounds to the tau electric dipole moment that are competitive with other high or low energy results.
Top pair production at a future $e^+e^-$ machine in a composite Higgs scenario
Barducci, Daniele; Moretti, Stefano; Pruna, Giovanni Marco
2015-01-01T23:59:59.000Z
The top quark plays a central role in many New Physics scenarios and in understanding the details of Electro-Weak Symmetry Breaking. In the short- and mid-term future, top-quark studies will mainly be driven by the experiments at the Large Hadron Collider. Exploration of top quarks will, however, be an integral part of particle physics studies at any future facility and an $e^+ e^-$ collider will have a very comprehensive top-quark physics program. We discuss the possibilities of testing NP in the top-quark sector within a composite Higgs scenario through deviations from the Standard Model in top pair production for different Centre-of-Mass energy options of a future $e^+e^-$ machine. In particular, we focus on precision studies of the top-quark sector at a CM energy ranging from 370 GeV up to 3 TeV.
Isovector pairing in odd-odd N=Z {sup 50}Mn.
O'Leary, C. D. O.; Bentley, M. A.; Lenzi, S. M.; Martinez-Pinedo, G.; Warner, D. D.; Bruce, A. M.; Cameron, J. A.; Carpenter, M. P.; Davids, C. N.; Fallon, P.; Frankland, L.; Gelletly, W.; Janssens, R. V. F.; Joss, D. T.; Lister, C. J.; Regan, P. H.; Reiter, P.; Rubio, B.; Seweryniak, D.; Svensson, C. E.; Vincent, S. M.; Williams, S. J.; Physics; Univ. of York; Univ. of Liverpool; Keele Univ.; Dipartimento di Fisica dell'Universit and INFN; Univ. Basel; CLRC Daresbury Lab.; Univ. of Brighton; McMaster Univ.; LBNL; Univ. of Surrey; CSIC-Uni.
2002-01-17T23:59:59.000Z
High-spin states in the odd-odd N=Z nucleus {sup 50}{sub 25}Mn have been investigated. A sequence of states up to J{sup {pi}}=6{sup +} has been assigned as the T=1 analogue of the yrast band in {sup 50}{sub 24}Cr for the first time. The differences in energy between levels in these bands are interpreted in terms of rotational alignments and the effect they have on the Coulomb energy of the nucleus. Comparisons with shell model calculations show that the Coulomb energy difference between the T=1 analogue structures is an important indicator of the competition between isovector pairing modes in N=Z nuclei and their isobars.
Large Gap Size Paired-end Library Construction for Second Generation Sequencing
Peng, Ze; Hamilton, Matthew; Froula, Jeff; Ewing, Aren; Foster, Brian; Cheng, Jan-Fang
2010-05-28T23:59:59.000Z
Fosmid or BAC end sequencing plays an important role in de novo assembly of large genomes like fungi and plants. However construction and Sanger sequencing of fosmid or BAC libraries are laborious and costly. The current 454 Paired-End (PE) Library and Illumina Jumping Library construction protocols are limited with the gap sizes of approximately 20 kb and 8 kb, respectively. In the attempt to understand the limitations of constructing PE libraries with greater than 30Kb gaps, we have purified 18, 28, 45, and 65Kb sheared DNA fragments from yeast and circularized the ends using the Cre-loxP approach described in the 454 PE Library protocol. With the increasing fragment sizes, we found a general trend of decreasing library quality in several areas. First, redundant reads and reads containing multiple loxP linkers increase when the average fragment size increases. Second, the contamination of short distance pairs (<10Kb) increases as the fragment size increases. Third, chimeric rate increases with the increasing fragment sizes. We have modified several steps to improve the quality of the long span PE libraries. The modification includes (1) the use of special PFGE program to reduce small fragment contamination; (2) the increase of DNA samples in the circularization step and prior to the PCR to reduce redundant reads; and (3) the decrease of fragment size in the double SPRI size selection to get a higher frequency of LoxP linker containing reads. With these modifications we have generated large gap size PE libraries with a much better quality.
Chandra Observations of the QSO Pair Q2345+007: Binary Quasar or Massive Dark Lens?
Paul J. Green; Chris Kochanek; Aneta Siemiginowska; Dong-Woo Kim; Maxim Markevitch; John Silverman; Anil Dosaj; Buell T. Jannuzi; Chris Smith
2002-02-04T23:59:59.000Z
The components of the wide (7.3") separation quasar pair Q2345+007A,B (z=2.15) have the most strikingly similar optical spectra seen to date (Steidel & Sargent 1991) yet no detected lensing mass, making this system the best candidate known for a massive (1e14 Msun) dark matter lens system. Here we present results from a 65ksec Chandra observation designed to investigate whether it is a binary quasar or a gravitational lens. We find no X-ray evidence for a lensing cluster to a (0.5-2keV) flux limit of 2e-15 cgs, which is consistent with lensing only for a reduced baryon fraction. Using the Chandra X-ray observations of the quasars themselves, together with new and published optical measurements, we use the observed emission properties of the quasars for further tests between the lens and binary hypotheses. Assuming similar line-of-sight absorption to the images, we find that their X-ray continuum slopes are inconsistent (Gamma_A=2.30 and Gamma_B=0.83) as are their X-ray to optical flux ratios. The probability that B suffers absorption sufficient to account for these spectral differences is negligible. We present new optical evidence that the flux ratio of the pair is variable, so the time-delay in a lens scenario could cause some of the discrepancies. However, adequately large variations in overall spectral energy distribution are rare in individual QSOs. All new evidence here weighs strongly toward the binary interpretation. Q2345+007 thus may represent the highest redshift example known of interaction-triggered but as-yet unmerged luminous AGN.
On the Pair Electromagnetic Pulse of a Black Hole with Electromagnetic Structure
Remo Ruffini; Jay D. Salmonson; James R. Wilson; She-Sheng Xue
1999-07-02T23:59:59.000Z
We study the relativistically expanding electron-positron pair plasma formed by the process of vacuum polarization around an electromagnetic black hole (EMBH). Such processes can occur for EMBH's with mass all the way up to $6\\cdot 10^5M_\\odot$. Beginning with a idealized model of a Reissner-Nordstrom EMBH with charge to mass ratio $\\xi=0.1$, numerical hydrodynamic calculations are made to model the expansion of the pair-electromagnetic pulse (PEM pulse) to the point that the system is transparent to photons. Three idealized special relativistic models have been compared and contrasted with the results of the numerically integrated general relativistic hydrodynamic equations. One of the three models has been validated: a PEM pulse of constant thickness in the laboratory frame is shown to be in excellent agreement with results of the general relativistic hydrodynamic code. It is remarkable that this precise model, starting from the fundamental parameters of the EMBH, leads uniquely to the explicit evaluation of the parameters of the PEM pulse, including the energy spectrum and the astrophysically unprecedented large Lorentz factors (up to $6\\cdot 10^3$ for a $10^3 M_{\\odot}$ EMBH). The observed photon energy at the peak of the photon spectrum at the moment of photon decoupling is shown to range from 0.1 MeV to 4 MeV as a function of the EMBH mass. Correspondingly the total energy in photons is in the range of $10^{52}$ to $10^{54}$ ergs, consistent with observed gamma-ray bursts. In these computations we neglect the presence of baryonic matter which will be the subject of forthcoming publications.
Remo Ruffini; Jay D. Salmonson; James R. Wilson; She-Sheng Xue
2000-04-18T23:59:59.000Z
The interaction of an expanding Pair-Electromagnetic pulse (PEM pulse) with a shell of baryonic matter surrounding a Black Hole with electromagnetic structure (EMBH) is analyzed for selected values of the baryonic mass at selected distances well outside the dyadosphere of an EMBH. The dyadosphere, the region in which a super critical field exists for the creation of electron-positron pairs, is here considered in the special case of a Reissner-Nordstrom geometry. The interaction of the PEM pulse with the baryonic matter is described using a simplified model of a slab of constant thickness in the laboratory frame (constant-thickness approximation) as well as performing the integration of the general relativistic hydrodynamical equations. The validation of the constant-thickness approximation, already presented in a previous paper Ruffini, et al.(1999) for a PEM pulse in vacuum, is here generalized to the presence of baryonic matter. It is found that for a baryonic shell of mass-energy less than 1% of the total energy of the dyadosphere, the constant-thickness approximation is in excellent agreement with full general relativistic computations. The approximation breaks down for larger values of the baryonic shell mass, however such cases are of less interest for observed Gamma Ray Bursts (GRBs). On the basis of numerical computations of the slab model for PEM pulses, we describe (i) the properties of relativistic evolution of a PEM pulse colliding with a baryonic shell; (ii) the details of the expected emission energy and observed temperature of the associated GRBs for a given value of the EMBH mass; 10^3 solar masses, and for baryonic mass-energies in the range 10^{-8} to 10^{-2} the total energy of the dyadosphere.
de Visser, P J; Guruswamy, T; Goldie, D J; Withington, S; Neto, A; Llombart, N; Baryshev, A M; Klapwijk, T M; Baselmans, J J A
2015-01-01T23:59:59.000Z
We have measured the absorption of terahertz radiation in a BCS superconductor over a broad range of frequencies from 200 GHz to 1.1 THz, using a broadband antenna-lens system and a tantalum microwave resonator. From low frequencies, the response of the resonator rises rapidly to a maximum at the gap edge of the superconductor. From there on the response drops to half the maximum response at twice the pair-breaking energy. At higher frequencies, the response rises again due to trapping of pair-breaking phonons in the superconductor. In practice this is the first measurement of the frequency dependence of the quasiparticle creation efficiency due to pair-breaking in a superconductor. The efficiency, calculated from the different non-equilibrium quasiparticle distribution functions at each frequency, is in agreement with the measurements.
Korteweg de Vries Burgers equation in multi-ion and pair-ion plasmas with Lorentzian electrons
Hussain, S.; Akhtar, N. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P. O. Nilore, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics (DPAM) PIEAS, P. O. Nilore, Islamabad 44000 (Pakistan)
2013-01-15T23:59:59.000Z
Korteweg de Vries Burgers equation for multi-ion and pair-ion plasmas has been derived using reductive perturbation technique. The kinematic viscosities of both positive and negative ions are taken into account. Generalized Lorentzian distribution is assumed for the electron component, accounting for deviation from Maxwellian equilibrium, parametrized via a real parameter {kappa}. The modification in the strength of shock structure is presented. A comprehensive comparison between the profiles of shock wave structure in multi-ion and pair-ion plasmas, (for the Maxwellian electrons to Lorentzian electrons), is discussed.
Production of $c \\bar c$ pairs at LHC: $k_t$-factorization and double-parton scattering
Antoni Szczurek
2012-06-01T23:59:59.000Z
We discuss charm production at LHC. The production of single $c \\bar c$ pairs is calculated in the $k_t$-factorization approach. We use several unintegrated gluon distributions from the literature. Differential distributions for several charmed mesons are presented and compared to recent results of the ALICE and LHCb collaborations. Some missing strength can be observed. Furthermore we discuss production of two $c \\bar c$ pairs within a simple formalism of double-parton scattering (DPS). Surprisingly large cross sections, comparable to single-parton scattering (SPS) contribution to $c \\bar c$ production, are predicted for LHC energies.
$(h_{11/2})^2$ alignments in neutron-rich $^{132}$Ba with negative-parity pairs
Yang Lei; Zhengyu Xu
2015-03-01T23:59:59.000Z
The shell-model collective-pair truncation with negative-parity pairs is adopted to study the $(h_{11/2})^2$ alignment in $^{132}$Ba. The proton $(h_{11/2})^2$-alignment state is predicted as an $E\\sim4.6$ MeV and $\\tau\\sim 0.5~\\mu$s isomer with relatively strong E3 decay channels. The oblately deformed neutron $(h_{11/2})^{-2}$ alignment in the yrast band and four negative-parity bands are confirmed, even although two of these negative-parity bands favor the prolate deformation, which directly manifests the $\\gamma$ unstability of $^{132}$Ba.
Fred Cooper; Gouranga C. Nayak
2006-02-21T23:59:59.000Z
We study the non-perturbative production of gluon pairs from a constant SU(3) chromo-electric background field via the Schwinger mechanism. We fix the covariant background gauge with an arbitrary gauge parameter \\alpha. We determine the transverse momentum distribution of the gluons, as well as the total probability of creating pairs per unit space time volume. We find that the result is independent of the covariant gauge parameter \\alpha used to define arbitrary covariant background gauges. We find that our non-perturbative result is both gauge invariant and gauge parameter \\alpha independent.
Gouranga C Nayak
2009-10-02T23:59:59.000Z
We study non-perturbative gluon pair production from arbitrary time dependent chromo-electric field E^a(t) with arbitrary color index a =1,2,...8 via Schwinger mechanism in arbitrary covariant background gauge \\alpha. We show that the probability of non-perturbative gluon pair production per unit time per unit volume per unit transverse momentum \\frac{dW}{d^4xd^2p_T} is independent of gauge fixing parameter \\alpha. Hence the result obtained in the Fynman-'t Hooft gauge, \\alpha=1, is the correct gauge invariant and gauge parameter \\alpha independent result.
Lu, Jianxu
2008-10-10T23:59:59.000Z
, Leon N. Cooper, and J. Robert Schrieffer [1], published the now famous BCS theory, and Found a electron with momentum planckover2pi1vectork and spin ? and a electron with momentum ?planckover2pi1vectork and spin ? near their common Fermi surfaces... to pair up into what is now known as a Cooper pair. When their energies, relative to the Fermi energy, are smaller than a cut-off energy planckover2pi1?D, a process of virtual exchanges of phonons between them will lead to an attractive interaction. Within...
Ilja Makkonen; Mikko M. Ervasti; Topi Siro; Ari Harju
2013-12-19T23:59:59.000Z
The correlated motion of a positron surrounded by electrons is a fundamental many-body problem. We approach this by modeling the momentum density of annihilating electron-positron pairs using the framework of reduced density matrices, natural orbitals and natural geminals (electron-positron pair wave functions) of the quantum theory of many-particle systems. We find that an expression based on the natural geminals provides an exact, unique and compact expression for the momentum density. The natural geminals can be used to define and determine enhancement factors for enhancement models going beyond the independent-particle model for a better understanding of results of positron annihilation experiments.