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1

Mechanical Systems that are both Classical and Quantum  

E-Print Network (OSTI)

Quantum dynamics can be regarded as a generalization of classical finite-state dynamics. This is a familiar viewpoint for workers in quantum computation, which encompasses classical computation as a special case. Here this viewpoint is extended to mechanics, where classical dynamics has traditionally been viewed as a macroscopic approximation of quantum behavior, not as a special case. When a classical dynamics is recast as a special case of quantum dynamics, the quantum description can be interpreted classically. For example, sometimes extra information is added to the classical state in order to construct the quantum description. This extra information is then eliminated by representing it in a superposition as if it were unknown information about a classical statistical ensemble. This usage of superposition leads to the appearance of Fermions in the quantum description of classical lattice-gas dynamics and turns continuous-space descriptions of finite-state systems into illustrations of classical sampling theory. A direct mapping of classical systems onto quantum systems also allows us to determine the minimum possible energy scale for a classical dynamics, based on a localized rate of state change. We use a partitioning description of dynamics to define locality, and discuss the ideal energy of two model systems.

Norman Margolus

2008-05-22T23:59:59.000Z

2

Background Independent Quantum Mechanics, Classical Geometric Forms and Geometric Quantum Mechanics-I  

E-Print Network (OSTI)

The geometry of the symplectic structures and Fubini-Study metric is discussed. Discussion in the paper addresses geometry of Quantum Mechanics in the classical phase space. Also, geometry of Quantum Mechanics in the projective Hilbert space has been discussed for the chosen Quantum states. Since the theory of classical gravity is basically geometric in nature and Quantum Mechanics is in no way devoid of geometry, the explorations pertaining to more and more geometry in Quantum Mechanics could prove to be valuable for larger objectives such as understanding of gravity.

Aalok Pandya

2008-09-08T23:59:59.000Z

3

Background Independent Quantum Mechanics, Classical Geometric Forms and Geometric Quantum Mechanics-II  

E-Print Network (OSTI)

The geometry of Quantum Mechanics in the context of uncertainty and complementarity, and probability is explored. We extend the discussion of geometry of uncertainty relations in wider perspective. Also, we discuss the geometry of probability in Quantum Mechanics and its interpretations. We give yet another interpretation to the notion of Faraday lines and loops as the locus of probability flow. Also, the possibilities of visualization of spectra of area operators by means of classical geometric forms and conventional Quantum Mechanics are explored.

Aalok Pandya

2009-01-19T23:59:59.000Z

4

The Born Rule in Quantum and Classical Mechanics  

E-Print Network (OSTI)

Considerable effort has been devoted to deriving the Born rule (e.g. that $|\\psi(x)|^2 dx$ is the probability of finding a system, described by $\\psi$, between $x$ and $x + dx$) in quantum mechanics. Here we show that the Born rule is not solely quantum mechanical; rather, it arises naturally in the Hilbert space formulation of {\\it classical} mechanics as well. These results provide new insights into the nature of the Born rule, and impact on its understanding in the framework of quantum mechanics.

Paul Brumer; Jiangbin Gong

2006-04-24T23:59:59.000Z

5

Complementarity and Classical Limit of Quantum Mechanics: Energy Measurement aspects  

E-Print Network (OSTI)

In the present contribution we discuss the role of experimental limitations in the classical limit problem. We studied some simple models and found that Quantum Mechanics does not re-produce classical mechanical predictions, unless we consider the experimental limitations ruled by uncertainty principle. We have shown that the discrete nature of energy levels of integrable systems can be accessed by classical measurements. We have defined a precise limit for this procedure. It may be used as a tool to define the classical limit as far as the discrete spectra of integrable systems are concerned. If a diffusive environment is considered, we conclude that the "lifetime" of discreteness is approximately $1/\\kappa$ ($\\kappa$ is the diffusion constant), thus it was possible to relate the classical limit of a spectra with the action of an environment and experimental resolution.

Adélcio C. Oliveira; Zolacir T. Oliveira Junior; Nestor S. Correia

2013-07-01T23:59:59.000Z

6

Statistical mechanics of classical and quantum computational complexity  

E-Print Network (OSTI)

The quest for quantum computers is motivated by their potential for solving problems that defy existing, classical, computers. The theory of computational complexity, one of the crown jewels of computer science, provides a rigorous framework for classifying the hardness of problems according to the computational resources, most notably time, needed to solve them. Its extension to quantum computers allows the relative power of quantum computers to be analyzed. This framework identifies families of problems which are likely hard for classical computers (``NP-complete'') and those which are likely hard for quantum computers (``QMA-complete'') by indirect methods. That is, they identify problems of comparable worst-case difficulty without directly determining the individual hardness of any given instance. Statistical mechanical methods can be used to complement this classification by directly extracting information about particular families of instances---typically those that involve optimization---by studying random ensembles of them. These pose unusual and interesting (quantum) statistical mechanical questions and the results shed light on the difficulty of problems for large classes of algorithms as well as providing a window on the contrast between typical and worst case complexity. In these lecture notes we present an introduction to this set of ideas with older work on classical satisfiability and recent work on quantum satisfiability as primary examples. We also touch on the connection of computational hardness with the physical notion of glassiness.

C. R. Laumann; R. Moessner; A. Scardicchio; S. L. Sondhi

2010-09-08T23:59:59.000Z

7

Euler & Lagrange versus Heisenberg & Schroedinger: Dynamical Pictures in Classical and Quantum Mechanics  

E-Print Network (OSTI)

Using quantum-classical analogies, we find that dynamical pictures of quantum mechanics have precise counterparts in classical mechanics. In particular, the Eulerian and Lagrangian descriptions of fluid dynamics in classical mechanics are the analogs of the Schroedinger and Heisenberg pictures in quantum mechanics, respectively. Similarities between classical and quantum dynamical pictures are explored within the framework of the Koopman-von Neumann formalism. These allow for a natural definition of various dynamical pictures in classical mechanics as well as the application of classical concepts to quantum dynamics. As an illustration, we use the interaction picture to find the classical evolution of an ensemble of particles of equal initial momenta and arbitrary configuration density under the action of a constant force in one dimension. As a second example, we discuss the extension of the ideas of sensitivity to initial conditions and chaos in classical mechanics to quantum mechanics.

M. Hossein Partovi

2013-05-22T23:59:59.000Z

8

On the hypothesis that quantum mechanism manifests classical mechanics: Numerical approach to the correspondence in search of quantum chaos  

SciTech Connect

Quantum manifestation of classical chaos has been one of the extensively studied subjects for more than a decade. Yet clear understanding of its nature still remains to be an open question partly due to the lack of a canonical definition of quantum chaos. The classical definition seems to be unsuitable in quantum mechanics partly because of the Heisenberg quantum uncertainty. In this regard, quantum chaos is somewhat misleading and needs to be clarified at the very fundamental level of physics. Since it is well known that quantum mechanics is more fundamental than classical mechanics, the quantum description of classically chaotic nature should be attainable in the limit of large quantum numbers. The focus of my research, therefore, lies on the correspondence principle for classically chaotic systems. The chaotic damped driven pendulum is mainly studied numerically using the split operator method that solves the time-dependent Schroedinger equation. For classically dissipative chaotic systems in which (multi)fractal strange attractors often emerge, several quantum dissipative mechanisms are also considered. For instance, Hoover`s and Kubo-Fox-Keizer`s approaches are studied with some computational analyses. But the notion of complex energy with non-Hermiticity is extensively applied. Moreover, the Wigner and Husimi distribution functions are examined with an equivalent classical distribution in phase-space, and dynamical properties of the wave packet in configuration and momentum spaces are also explored. The results indicate that quantum dynamics embraces classical dynamics although the classicalquantum correspondence fails to be observed in the classically chaotic regime. Even in the semi-classical limits, classically chaotic phenomena would eventually be suppressed by the quantum uncertainty.

Lee, Sang-Bong

1993-09-01T23:59:59.000Z

9

Quantum mechanical and information theoretic view on classical glass transitions  

E-Print Network (OSTI)

Using the mapping of the Fokker-Planck description of classical stochastic dynamics onto a quantum Hamiltonian, we argue that a dynamical glass transition in the former must have a precise definition in terms of a quantum phase transition in the latter. At the dynamical level, the transition corresponds to a collapse of the excitation spectrum at a critical point. At the static level, the transition affects the ground state wavefunction: while in some cases it could be picked up by the expectation value of a local operator, in others the order may be non-local, and impossible to be determined with any local probe. Here we propose instead to use concepts from quantum information theory that are not centered around local order parameters, such as fidelity and entanglement measures. We show that for systems derived from the mapping of classical stochastic dynamics, singularities in the fidelity susceptibility translate directly into singularities in the heat capacity of the classical system. In classical glassy systems with an extensive number of metastable states, we find that the prefactor of the area law term in the entanglement entropy jumps across the transition. We also discuss how entanglement measures can be used to detect a growing correlation length that diverges at the transition. Finally, we illustrate how static order can be hidden in systems with a macroscopically large number of degenerate equilibrium states by constructing a three dimensional lattice gauge model with only short-range interactions but with a finite temperature continuous phase transition into a massively degenerate phase.

Claudio Castelnovo; Claudio Chamon; David Sherrington

2010-03-19T23:59:59.000Z

10

Mecanica Clasica (Classical Mechanics)  

E-Print Network (OSTI)

First Internet undergraduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

Rosu, H C

1999-01-01T23:59:59.000Z

11

Erasing the traces of classical mechanics in ionization of H{sub 2} by quantum interferences  

SciTech Connect

The single ionization of hydrogen molecules by fast electron impact is studied theoretically for transitions from the ground (gerade) state to final ground (gerade) and first-excited (ungerade) states of H{sub 2}{sup +}. It is shown that under definite conditions and for particular orientations of the molecule, the main physical features of the ionization reaction, which are the binary and recoil peaks usually associated with classical mechanisms, are completely erased by quantum interference effects that resemble the ones predicted previously for photoionization reactions. However, these new effects cannot be derived from photoionization results, as the electromagnetic field cannot transfer momentum. In addition, it is found that the emission spectra of transitions leading to the final gerade and ungerade states of the H{sub 2}{sup +} residual target are analogous in certain cases to the patterns of two sources emitting waves in phase or antiphase, respectively. Finally, we show how an average of the emission from randomly oriented molecules produces a binary peak at the classical expected position, in agreement with experiments.

Fojon, O. A.; Stia, C. R.; Rivarola, R. D. [Laboratorio de Colisiones Atomicas and Instituto de Fisica Rosario, CONICET-UNR, Avenida Pellegrini 250, 2000 Rosario (Argentina)

2011-09-15T23:59:59.000Z

12

Quantum Money with Classical Verification  

E-Print Network (OSTI)

We construct a quantum money scheme that allows verification through classical communication with bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification.

Gavinsky, Dmitry

2011-01-01T23:59:59.000Z

13

Quantum Money with Classical Verification  

E-Print Network (OSTI)

We propose and construct a quantum money scheme that allows verification through classical communication with a bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification. Our scheme is secure against adaptive adversaries - this property is not directly related to the possibility of classical verification, nevertheless none of the earlier quantum money constructions is known to possess it.

Dmitry Gavinsky

2011-09-02T23:59:59.000Z

14

Classical and Quantum-Mechanical Axioms with the Higher Time Derivative Formalism  

E-Print Network (OSTI)

A Newtonian mechanics model is essentially the model of a point body in an inertial reference frame. How to describe extended bodies in non-inertial (vibrational) reference frames with the random initial conditions? One of the most general description (known as the higher derivatives formalism) consists in taking into account the infinite number of the higher order temporal derivatives of the coordinates in the Lagrange function. Such formalism describes physical objects in the in?finite dimensional space does not contradict quantum mechanics and infinite dimensional Hilbert space.

Timur Kamalov

2013-07-04T23:59:59.000Z

15

Numerical Classical and Quantum Mechanical simulations of Charge Density wave models  

E-Print Network (OSTI)

We first present how to do a computer simulation of Charge Density Waves using a driven harmonic oscillator model by a numerical scheme as initially formulated by Littlewood, and then afterwards use this to present how the dielectric model as presented by this proceedure leads to a blow up at the initialization of a threshold field ET. We find that this is highly unphysical and this initiated our inquiry as to alternative models. Afterwards, we then investigate hwo to present this transport problem of CDW quantum mechanically, threough a numerical simulation of the massive Schwinger model. We find that this single chaing quantum mechanical simulation uwed to formulate solutions to CDW transport in itself is insufficient for transport of solitons(anti-solitons) through a pinning gap model of CDW. We show that a model Hamiltonian with Peierls condensation energy used to couple adjacent chains (or transverse wave vectors) permits formation of solitons (anti- solitons) which can be used to transport CDW through a potential barrier. This addition of the Peierls condensation energy term is essential for any quantum model of Charge Density Waves to give tunneling behavior as seen via a numerical simulation.

A. W. Beckwith

2004-09-13T23:59:59.000Z

16

QUICK QUANTUM MECHANICS ---Introduction ---  

E-Print Network (OSTI)

QUICK QUANTUM MECHANICS --- Introduction --- The following notes are intended to be a supplement to your study of Liboff's ``Introductory Quantum Mechanics.'' They are not an alternative! My purpose here of Classical Mechanics After Newton found his equations of motion, physicists knew they would have to wait

Jackson, Andrew D.

17

Testing quantum mechanics  

E-Print Network (OSTI)

As experiments continue to push the quantum-classical boundary to include increasingly complex dynamical systems, the interpretation of experimental data becomes more and more challenging: when the observations are noisy, indirect, and limited, how can we be sure that we are observing quantum behavior? This tutorial highlights some of the difficulties in such experimental tests of quantum mechanics, using optomechanics as the central example, and discusses how the issues can be resolved using techniques from statistics and insights from quantum information theory.

Mankei Tsang

2013-06-12T23:59:59.000Z

18

Quantum and Classical Variance in the Quantum Realm  

E-Print Network (OSTI)

This paper examines the variance of quantum and classical predictions in the quantum realm, as well as unexpected presence and absence of variances. Some features are found that share an indirect commonality with the Aharonov-Bohm and Aharonov-Casher effects in that there is a quantum action in the absence of a force. Variances are also found in the presence of a force that are more subtle as they are of higher order. Significant variances related to the harmonic oscillator and particle in a box periods are found. This paper raises the question whether apparent quantum self-inconsistency may be examined internally, or must be empirically ascertained. These inherent variances may either point to inconsistencies in quantum mechanics that should be fixed, or that nature is manifestly more non-classical than expected. For the harmonic oscillator it is proven that the second spatial moment is the same in QM and CM.

Mario Rabinowitz

2007-07-08T23:59:59.000Z

19

Quantum Computation: Towards the Construction of a `Between Quantum and Classical Computer'  

E-Print Network (OSTI)

Quantum Computation: Towards the Construction of a `Between Quantum and Classical Computer-Mails: diraerts@vub.ac.be, bdhooghe@vub.ac.be Abstract Using the `between quantum and classical' models that have been constructed explicitly within the hidden measurement approach of quantum mechanics we investigate

Aerts, Diederik

20

Classical and quantum randomness and the financial market  

E-Print Network (OSTI)

We analyze complexity of financial (and general economic) processes by comparing classical and quantum-like models for randomness. Our analysis implies that it might be that a quantum-like probabilistic description is more natural for financial market than the classical one. A part of our analysis is devoted to study the possibility of application of the quantum probabilistic model to agents of financial market. We show that, although the direct quantum (physical) reduction (based on using the scales of quantum mechanics) is meaningless, one may apply so called quantum-like models. In our approach quantum-like probabilistic behaviour is a consequence of contextualy of statistical data in finances (and economics in general). However, our hypothesis on "quantumness" of financial data should be tested experimentally (as opposed to the conventional description based on the noncontextual classical probabilistic approach). We present a new statistical test based on a generalization of the well known in quantum physics Bell's inequality.

Andrei Khrennikov

2007-04-22T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Wave-Particle Duality in Classical Mechanics  

E-Print Network (OSTI)

Until recently, wave-particle duality has been thought of as quantum principle without a counterpart in classical physics. This belief was challenged after (i) finding that average dynamics of a classical particle in strong inhomogeneous oscillating field resembles that of a quantum object and (ii) experimental discovery of "walkers" - macroscopic droplets that bounce on a vertically vibrating bath of the same fluid and can self-propell via interaction with the surface waves they generate. This paper exposes a new family of objects that can display both particle and wave features all together while strictly obeying laws of the Newtonian mechanics. In contrast to the previously known duality examples in classical physics, oscillating field or constant inflow of energy are not required for their existence. These objects behave deterministically provided that all their degrees of freedom are known to an observer. If, however, some degrees of freedom are unknown, observer can describe such objects only {\\it probabilistically} and they manifest {\\it weird} features similar to that of quantum particles. We show new classical counterparts of such quantum phenomena as particle interference, tunneling, above-barrier reflection, trapping on top of a barrier, and spontaneous emission of radiation. In the light of these findings, we hypothesize that quantum mechanics may \\emph{emerge} as approximation from a more profound theory on a deeper level.

Alexander Y. Davydov

2012-01-21T23:59:59.000Z

22

Quantum-Classical Correspondence in Nonrelativistic Electrodynamics  

SciTech Connect

A form of classical electrodynamic field exists which gives exact agreement with the operator field of quantum electrodynamics (QED) for the Lamb shift of a harmonically bound point electron. Here it is pointed out that this form of classical theory with its physically acceptable interpretation is the result of an unconventional resolution of a mathematically ambiguous term in classical field theory. Finally a quantum-classical correspondence principle is shown to exist in the sense that the classical field and expectation value of the QED operator field are identical if retardation is neglected in the latter.

Ritchie, A.B.; Weatherford, C.A.

1999-10-14T23:59:59.000Z

23

Quantum classical correspondence in nonrelativistic electrodynamics  

SciTech Connect

A form of classical electrodynamic field exists which gives exact agreement with the operator field of quantum electrodynamics (QED) for the Lamb shift of a harmonically bound point electron. Here it is pointed out that this form of classical theory, with its physically acceptable interpretation, is the result of an unconventional resolution of a mathematically ambiguous term in classical field theory. Finally, a quantum classical correspondence principle is shown to exist in the sense that the classical field and expectation value of the QED operator field are identical, if retardation is neglected in the latter.

Ritchie, B.; Weatherford, C.A.

1999-12-01T23:59:59.000Z

24

Physicalism versus quantum mechanics  

E-Print Network (OSTI)

Foundations of Quantum Mechanics. (Princeton UniversityMind, Matter, and Quantum Mechanics, (Springer, Berlin & NewMindful Universe: Quantum Mechanics and the Participating

Stapp, Henry P; Theoretical Physics Group; Physics Division

2009-01-01T23:59:59.000Z

25

Classical and quantum correlative capacities of quantum systems  

SciTech Connect

How strongly can one system be correlated with another? In the classical world, this basic question concerning correlative capacity has a very satisfying answer: The ''effective size'' of the marginal system, as quantified by the Shannon entropy, sets a tight upper bound to the correlations, as quantified by the mutual information. Although in the quantum world bipartite correlations, like their classical counterparts, are also well quantified by mutual information, the similarity ends here: The correlations in a bipartite quantum system can be twice as large as the marginal entropy. In the paradigm of quantum discord, the correlations are split into classical and quantum components, and it was conjectured that both the classical and quantum correlations are (like the classical mutual information) bounded above by each subsystem's entropy. In this work, by exploiting the interplay between entanglement of formation, mutual information, and quantum discord, we disprove that conjecture. We further indicate a scheme to restore harmony between quantum and classical correlative capacities. The results illustrate dramatically the asymmetric nature of quantum discord and highlight some subtle and unusual features of quantum correlations.

Li Nan; Luo Shunlong [Academy of Mathematics and Systems Science, Chinese Academy of Sciences, 100190 Beijing (China)

2011-10-15T23:59:59.000Z

26

Quantum Optical Version of Classical Optical Transformations and Beyond  

E-Print Network (OSTI)

By the newly developed technique of integration within an ordered product (IWOP) of operators, we explore quantum optical version of classical optical transformations such as optical Fresnel transform, Hankel transform, fractional Fourier transform, Wigner transform, wavelet transform and Fresnel-Hadmard combinatorial transform etc. In this way one may gain benefit for developing classical optics theory from the research in quantum optics, or vice-versa. We can not only find some new quantum mechanical unitary operators which correspond to the known optical transformations, deriving a new theorem for calculating quantum tomogram of density operators, but also can reveal some new classical optical transformations. We derive GFO's normal product form and its canonical coherent state representation and find that GFO is the loyal representation of symplectic group multiplication rule. We show that GFT is just the transformation matrix element of GFO in the coordinate representation such that two successive GFTs is still a GFT. The ABCD rule of the Gaussian beam propagation is directly demonstrated in the context of quantum optics. Especially, the introduction of quantum mechanical entangled state representations opens up a new area to finding new classical optical transformations. The complex wavelet transform and the condition of mother wavelet are studied in the context of quantum optics too. Throughout our discussions, the coherent state, the entangled state representation of the two-mode squeezing operators and the IWOP technique are fully used. All these confirms Dirac's assertion: " ... for a quantum dynamic system that has a classical analogue, unitary transformation in the quantum theory is the analogue of contact transformation in the classical theory".

Hong-yi Fan; Li-yun Hu

2010-10-03T23:59:59.000Z

27

Stock Mechanics: a classical approach  

E-Print Network (OSTI)

New theoretical approaches about forecasting stock markets are proposed. A mathematization of the stock market in terms of arithmetical relations is given, where some simple (non-differential, non-fractal) expressions are also suggested as general stock price formuli in closed forms which are able to generate a variety of possible price movements in time. A kind of mechanics is submitted to cover the price movements in terms of classical concepts. Where utilizing stock mechanics to grow the portfolios in real markets is also proven.

Tuncay, C

2005-01-01T23:59:59.000Z

28

Quantum Mechanics and Multiply Connected Spaces  

E-Print Network (OSTI)

t is well known that the difference between Quantum Mechanics and Classical Theory appears most crucially in the non Classical spin half of the former theory and the Wilson-Sommerfelt quantization rule. We argue that this is symptomatic of the fact that Quantum Theory is actually a theory in multiply connected space while Classical Theory operates in simply connected space.

B. G. Sidharth

2006-05-16T23:59:59.000Z

29

From Classical To Quantum Gravity: Introduction to Loop Quantum Gravity  

E-Print Network (OSTI)

We present an introduction to the canonical quantization of gravity performed in loop quantum gravity, based on lectures held at the 3rd quantum geometry and quantum gravity school in Zakopane in 2011. A special feature of this introduction is the inclusion of new proposals for coupling matter to gravity that can be used to deparametrize the theory, thus making its dynamics more tractable. The classical and quantum aspects of these new proposals are explained alongside the standard quantization of vacuum general relativity in loop quantum gravity.

Giesel, Kristina

2012-01-01T23:59:59.000Z

30

Effective equations for the quantum pendulum from momentous quantum mechanics  

SciTech Connect

In this work we study the quantum pendulum within the framework of momentous quantum mechanics. This description replaces the Schroedinger equation for the quantum evolution of the system with an infinite set of classical equations for expectation values of configuration variables, and quantum dispersions. We solve numerically the effective equations up to the second order, and describe its evolution.

Hernandez, Hector H.; Chacon-Acosta, Guillermo [Universidad Autonoma de Chihuahua, Facultad de Ingenieria, Nuevo Campus Universitario, Chihuahua 31125 (Mexico); Departamento de Matematicas Aplicadas y Sistemas, Universidad Autonoma Metropolitana-Cuajimalpa, Artificios 40, Mexico D. F. 01120 (Mexico)

2012-08-24T23:59:59.000Z

31

Course Syllabus PHYS 331 Advanced Classical Mechanics  

E-Print Network (OSTI)

Course Syllabus PHYS 331 ­ Advanced Classical Mechanics Fall 2011 Instructor: Ben Vollmayr-Lee, Olin 168, ben.vollmayr-lee@bucknell.edu, x73106 Textbook: John Taylor, Classical Mechanics Office Hours://www.eg.bucknell.edu/bvollmay/phys331 Course Description Classical mechanics is where it all started. Newton demonstrated that the same

Vollmayr-Lee, Ben

32

Quantum chaos in elementary quantum mechanics  

E-Print Network (OSTI)

chaos in elementary quantum mechanics so-called integrableIntroduction to Quantum Mechanics (Englewoods Cliff, NJ:Lifshitz E M 1977 Quantum Mechanics (New York: Pergamon) [

Dabaghian, Yuri A; Jensen, R

2005-01-01T23:59:59.000Z

33

Simultaneous classical-quantum capacities of quantum multiple access channels  

E-Print Network (OSTI)

The rates at which classical and quantum information can be simultaneously transmitted from two spatially separated senders to a single receiver over an arbitrary quantum channel are characterized. Two main results are proved in detail. The first describes the region of rates at which one sender can send classical information while the other sends quantum information. The second describes those rates at which both senders can send quantum information. For each of these situations, an example of a channel is given for which the associated region admits a single-letter description. This is the author's Ph.D. dissertation, submitted to the Department of Electrical Engineering at Stanford University in March, 2005. It represents an expanded version of the paper quant-ph/0501045, containing a number of tutorial chapters which may be of independent interest for those learning about quantum Shannon theory.

Jon Yard

2005-06-06T23:59:59.000Z

34

Unifying classical and quantum key distillation  

E-Print Network (OSTI)

Assume that two distant parties, Alice and Bob, as well as an adversary, Eve, have access to (quantum) systems prepared jointly according to a tripartite state. In addition, Alice and Bob can use local operations and authenticated public classical communication. Their goal is to establish a key which is unknown to Eve. We initiate the study of this scenario as a unification of two standard scenarios: (i) key distillation (agreement) from classical correlations and (ii) key distillation from pure tripartite quantum states. Firstly, we obtain generalisations of fundamental results related to scenarios (i) and (ii), including upper bounds on the key rate. Moreover, based on an embedding of classical distributions into quantum states, we are able to find new connections between protocols and quantities in the standard scenarios (i) and (ii). Secondly, we study specific properties of key distillation protocols. In particular, we show that every protocol that makes use of pre-shared key can be transformed into an equally efficient protocol which needs no pre-shared key. This result is of practical significance as it applies to quantum key distribution (QKD) protocols, but it also implies that the key rate cannot be locked with information on Eve's side. Finally, we exhibit an arbitrarily large separation between the key rate in the standard setting where Eve is equipped with quantum memory and the key rate in a setting where Eve is only given classical memory. This shows that assumptions on the nature of Eve's memory are important in order to determine the correct security threshold in QKD.

Matthias Christandl; Artur Ekert; Michal Horodecki; Pawel Horodecki; Jonathan Oppenheim; Renato Renner

2006-08-25T23:59:59.000Z

35

Unifying classical and quantum key distillation  

E-Print Network (OSTI)

Assume that two distant parties, Alice and Bob, as well as an adversary, Eve, have access to (quantum) systems prepared jointly according to a tripartite state ?ABE. In addition, Alice and Bob can use local operations and authenticated public classical communication. Their goal is to establish a key which is unknown to Eve. We initiate the study of this scenario as a unification of two standard scenarios: (i) key distillation (agreement) from classical correlations and (ii) key distillation from pure tripartite quantum states. Firstly, we obtain generalisations of fundamental results related to scenarios (i) and (ii), including upper bounds on the key rate, i.e., the number of key bits that can be extracted per copy of ?ABE. Moreover, based on an embedding of classical distributions into quantum states, we are able to find new connections between protocols and quantities in the standard scenarios (i) and (ii). Secondly, we study specific properties of key distillation protocols. In particular, we show that every protocol that makes use of pre-shared key can be transformed into an equally efficient protocol which needs no pre-shared key. This result is of practical significance as it applies to quantum key distribution (QKD) protocols, but it also implies that the key rate cannot be locked with information on Eve’s side. Finally, we exhibit an arbitrarily large separation between the key rate in the standard setting where Eve is equipped with quantum memory and the key rate in a setting where Eve is only given classical memory. This shows that assumptions on the nature of Eve’s memory are important in order to determine the correct security threshold in QKD. 1

Matthias Christ; Renato Renner

2008-01-01T23:59:59.000Z

36

Can quantum computer perform better than classical?  

E-Print Network (OSTI)

A theoretical model of a quantum device which can factorize any number N in two steps i.e. by preparing an input state and performing a measurement is discussed. The analysis reveals that the duration of state preparation and measurement is proportional to N while the energy consumption grows like log N. These results suggest the existence of Heisenberg-type relation putting limits on the efficiency of a quantum computer in terms of a total computation time, a total energy consumption and a classical complexity of the problem.

Robert Alicki

2000-06-05T23:59:59.000Z

37

Can quantum computer perform better than classical?  

E-Print Network (OSTI)

A theoretical model of a quantum device which can factorize any number N in two steps i.e. by preparing an input state and performing a measurement is discussed. The analysis reveals that the duration of state preparation and measurement is proportional to N while the energy consumption grows like log N. These results suggest the existence of Heisenberg-type relation putting limits on the efficiency of a quantum computer in terms of a total computation time, a total energy consumption and a classical complexity of the problem.

Alicki, R

2000-01-01T23:59:59.000Z

38

Quantum Mechanics Measurements, Mutually  

E-Print Network (OSTI)

Quantum Mechanics Measurements, Mutually Unbiased Bases and Finite Geometry Or why six is the first) #12;Quantum Mechanics for Dummies Finite dimensional quantum states are represented by trace one,1 -icS1,1[ ] #12;Quantum systems evolve and are measured. The evolution of a quantum system using

Gruner, Daniel S.

39

Classical Mechanics (Prof. P. L. Read)  

E-Print Network (OSTI)

Classical Mechanics (Prof. P. L. Read) Lecture 1 Photograph © Andrew Dunn, 5 November 2004. #12;What is Classical Mechanics? · .. rational mechanics will be the science of motion resulting from any Mechanics? · System of mathematical physics developed since the time of Galileo, Newton & Kepler · Concerned

Read, Peter L.

40

Bohmian mechanics contradicts quantum mechanics  

E-Print Network (OSTI)

Bohmian mechanics contradicts quantum mechanics Arnold Neumaier Institut fur Mathematik, Universit://solon.cma.univie.ac.at/#24;neum/ Abstract. It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can

Neumaier, Arnold

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Picturing classical and quantum Bayesian inference  

E-Print Network (OSTI)

We introduce a graphical framework for Bayesian inference that is sufficiently general to accommodate not just the standard case but also recent proposals for a theory of quantum Bayesian inference wherein one considers density operators rather than probability distributions as representative of degrees of belief. The diagrammatic framework is stated in the graphical language of symmetric monoidal categories and of compact structures and Frobenius structures therein, in which Bayesian inversion boils down to transposition with respect to an appropriate compact structure. We characterize classical Bayesian inference in terms of a graphical property and demonstrate that our approach eliminates some purely conventional elements that appear in common representations thereof, such as whether degrees of belief are represented by probabilities or entropic quantities. We also introduce a quantum-like calculus wherein the Frobenius structure is noncommutative and show that it can accommodate Leifer's calculus of `cond...

Coecke, Bob

2011-01-01T23:59:59.000Z

42

Tomographic Quantum Cryptography: Equivalence of Quantum and Classical Key Distillation  

E-Print Network (OSTI)

The security of a cryptographic key that is generated by communication through a noisy quantum channel relies on the ability to distill a shorter secure key sequence from a longer insecure one. For an important class of protocols, which exploit tomographically complete measurements on entangled pairs of any dimension, we show that the noise threshold for classical advantage distillation is identical with the threshold for quantum entanglement distillation. As a consequence, the two distillation procedures are equivalent: neither offers a security advantage over the other.

Dagmar Bruss; Matthias Christandl; Artur Ekert; Berthold-Georg Englert; Dagomir Kaszlikowski; Chiara Macchiavello

2003-03-31T23:59:59.000Z

43

Quantum Mechanics Dung-Hai Lee  

E-Print Network (OSTI)

Quantum Mechanics Dung-Hai Lee Summer 2000 #12;Contents 1 A brief reminder of linear Algebra 3 1.5 Bell's inequality . . . . . . . . . . . . . . . . . . . . . . . 20 3 Quantum dynamics 23 3 . . . . . . . . . . . . . . . . . . . 43 3.12 Classical approximation . . . . . . . . . . . . . . . . . . 45 3.13 Quantum statistical

Murayama, Hitoshi

44

Quantum-"classical" correspondence in a nonadiabatic-transition system  

E-Print Network (OSTI)

A nonadiabatic-transition system which exhibits ``quantum chaotic'' behavior [Phys. Rev. E {\\bf 63}, 066221 (2001)] is investigated from quasi-classical aspects. Since such a system does not have a naive classical limit, we take the mapping approach by Stock and Thoss [Phys. Rev. Lett. {\\bf 78}, 578 (1997)] to represent the quasi-classical dynamics of the system. We numerically show that there is a sound correspondence between the quantum chaos and classical chaos for the system.

Fujisaki, H

2004-01-01T23:59:59.000Z

45

Quantum-"classical" correspondence in a nonadiabatic-transition system  

E-Print Network (OSTI)

A nonadiabatic-transition system which exhibits ``quantum chaotic'' behavior [Phys. Rev. E {\\bf 63}, 066221 (2001)] is investigated from quasi-classical aspects. Since such a system does not have a naive classical limit, we take the mapping approach by Stock and Thoss [Phys. Rev. Lett. {\\bf 78}, 578 (1997)] to represent the quasi-classical dynamics of the system. We numerically show that there is a sound correspondence between the quantum chaos and classical chaos for the system.

Hiroshi Fujisaki

2004-01-22T23:59:59.000Z

46

PERSPECTIVE Quantum Mechanics of Black Holes  

E-Print Network (OSTI)

PERSPECTIVE Quantum Mechanics of Black Holes Edward Witten The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived

47

A new stochastic interpretation of quantum mechanics  

E-Print Network (OSTI)

The reinterpretation of quantum mechanical formalism in terms of a classical model with a continuous material "$\\Psi$-field" acting upon a point-like particle which is subjected to large friction and random forces is proposed. This model gives a mechanism for sudden "quantum jumps" and provides a simple explanation of "Schrödinger Cat" phenomena.

Alicki, R

1997-01-01T23:59:59.000Z

48

A new stochastic interpretation of quantum mechanics  

E-Print Network (OSTI)

The reinterpretation of quantum mechanical formalism in terms of a classical model with a continuous material "$\\Psi$-field" acting upon a point-like particle which is subjected to large friction and random forces is proposed. This model gives a mechanism for sudden "quantum jumps" and provides a simple explanation of "Schr\\"odinger Cat" phenomena.

Robert Alicki

1997-11-24T23:59:59.000Z

49

Picturing classical and quantum Bayesian inference  

E-Print Network (OSTI)

We introduce a graphical framework for Bayesian inference that is sufficiently general to accommodate not just the standard case but also recent proposals for a theory of quantum Bayesian inference wherein one considers density operators rather than probability distributions as representative of degrees of belief. The diagrammatic framework is stated in the graphical language of symmetric monoidal categories and of compact structures and Frobenius structures therein, in which Bayesian inversion boils down to transposition with respect to an appropriate compact structure. We characterize classical Bayesian inference in terms of a graphical property and demonstrate that our approach eliminates some purely conventional elements that appear in common representations thereof, such as whether degrees of belief are represented by probabilities or entropic quantities. We also introduce a quantum-like calculus wherein the Frobenius structure is noncommutative and show that it can accommodate Leifer's calculus of `conditional density operators'. The notion of conditional independence is also generalized to our graphical setting and we make some preliminary connections to the theory of Bayesian networks. Finally, we demonstrate how to construct a graphical Bayesian calculus within any dagger compact category.

Bob Coecke; Robert W. Spekkens

2011-02-11T23:59:59.000Z

50

Quantum mechanics needs no interpretation  

E-Print Network (OSTI)

Probabilistic description of results of measurements and its consequences for understanding quantum mechanics are discussed. It is shown that the basic mathematical structure of quantum mechanics like the probability amplitude, Born rule, probability density current, commutation relations, momentum operator, uncertainty relations, rules for including the scalar and vector potentials and existence of antiparticles can be derived from the definition of the mean values of the space coordinates and time. Equations of motion of quantum mechanics, the Klein-Gordon equation, Schroedinger equation and Dirac equation are obtained from requirement of the relativistic invariance of the theory. Limit case of localized probability densities leads to the Hamilton-Jacobi equation of classical mechanics. Many particle systems are also discussed.

L. Skala; V. Kapsa

2004-12-22T23:59:59.000Z

51

Complementarity of quantum discord and classically accessible information  

E-Print Network (OSTI)

The sum of the Holevo quantity (that bounds the capacity of quantum channels to transmit classical information about an observable) and the quantum discord (a measure of the quantumness of correlations of that observable) yields an observable-independent total given by the quantum mutual information. This split naturally delineates information about quantum systems accessible to observers -- information that is redundantly transmitted by the environment -- while showing that it is maximized for the quasi-classical pointer observable. Other observables are accessible only via correlations with the pointer observable. Further, we prove an anti-symmetry property relating accessible information and discord. It shows that information becomes objective -- accessible to many observers -- only as quantum information is relegated to correlations with the global environment, and, therefore, locally inaccessible. The resulting complementarity explains why, in a quantum Universe, we perceive objective classical reality while flagrantly quantum superpositions are out of reach.

Michael Zwolak; Wojciech H. Zurek

2013-03-19T23:59:59.000Z

52

Generalized Partitioned Quantum Cellular Automata and Quantization of Classical CA  

E-Print Network (OSTI)

In this paper, in order to investigate natural transformations from discrete CA to QCA, we introduce a new formulation of finite cyclic QCA and generalized notion of partitioned QCA. According to the formulations, we demonstrate the condition of local transition functions, which induce a global transition of well-formed QCA. Following the results, extending a natural correspondence of classical cells and quantum cells to the correspondence of classical CA and QCA, we have the condition of classical CA such that CA generated by quantumization of its cells is well-formed QCA. Finally we report some results of computer simulations of quantumization of classical CA.

Shuichi Inokuchi; Yoshihiro Mizoguchi

2003-12-11T23:59:59.000Z

53

Quantum Statistical Mechanics and Quantum Computation  

E-Print Network (OSTI)

Quantum Statistical Mechanics and Quantum Computation 22-23 March 2012 Room 111, Jadwin Hall, focused meeting to explore the intersection between quantum statistical mechanics and quantum computation, specifically quantum complexity theory. Advances in complexity theory have interesting implications for physics

54

Quantum size effects in classical hadrodynamics  

SciTech Connect

The author discusses future directions in the development of classical hydrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic nucleus-nucleus collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. The present version of the theory includes only the neutral scalar ({sigma}) and neutral vector ({omega}) meson fields. In the future, additional isovector pseudoscalar ({pi}{sup +}, {pi}{sup {minus}}, {pi}{sup 0}), isovector vector ({rho}{sup +}, {rho}{sup {minus}}, {rho}{sup 0}), and neutral pseudoscalar ({eta}) meson fields should be incorporated. Quantum size effects should be included in the equations of motion by use of the spreading function of Moniz and Sharp, which generates an effective nucleon mass density smeared out over a Compton wavelength. However, unlike the situation in electrodynamics, the Compton wavelength of the nucleon is small compared to its radius, so that effects due to the intrinsic size of the nucleon dominate.

Nix, J.R.

1994-03-01T23:59:59.000Z

55

Inverse Problems in Classical and Quantum Physics  

E-Print Network (OSTI)

The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. In this thesis, als...

Almasy, Andrea A

2009-01-01T23:59:59.000Z

56

How do black holes move, as quantum objects or as classical objects?  

E-Print Network (OSTI)

Results of a recent study of the transition between quantum and classical behavior are applied to black holes. The study led to a criterion separating quantum from classical behavior on the basis of mass or size, dependent on local effects of cosmic expansion. Application of this criterion to black holes indicates that the motion of smaller black holes will be characteristically quantum mechanical, while the motion of larger black holes must be classical, with a threshold distinguishing these behaviors at a Schwartzschild radius of roughly the size of a nucleon.

C. L. Herzenberg

2007-09-12T23:59:59.000Z

57

The equation of motion of an electron : a debate in classical and quantum physics.  

SciTech Connect

The current status of understanding of the equation of motion of an electron is summarized. Classically, a consistent, linearized theory exists for an electron of finite extent, as long as the size of the electron is larger than the classical electron radius. Nonrelativistic quantum mechanics seems to offer a tine theory even in the point-particle limit.

Kim, K.-J.

1999-01-27T23:59:59.000Z

58

Inverse Problems in Classical and Quantum Physics  

E-Print Network (OSTI)

The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. In this thesis, also two approaches of EIT image reconstruction are proposed. The first is based on reformulating the inverse problem in terms of integral equations. This method uses only a single set of measurements for the reconstruction. The second approach is an algorithm based on linearisation which uses more then one set of measurements. A promising result is that one can qualitatively reconstruct the conductivity inside the cross-section of a human chest. Even though the human volunteer is neither two-dimensional nor circular, such reconstructions can be useful in medical applications: monitoring for lung problems such as accumulating fluid or a collapsed lung and noninvasive monitoring of heart function and blood flow.

Andrea A. Almasy

2009-12-02T23:59:59.000Z

59

Quantum mechanical Universal constructor  

E-Print Network (OSTI)

Arbitrary quantum states cannot be copied. In fact, to make a copy we must provide complete information about the system. However, can a quantum system self-replicate? This is not answered by the no-cloning theorem. In the classical context, Von Neumann showed that a `universal constructor' can exist which can self-replicate an arbitrary system, provided that it had access to instructions for making copy of the system. We question the existence of a universal constructor that may allow for the self-replication of an arbitrary quantum system. We prove that there is no deterministic universal quantum constructor which can operate with finite resources. Further, we delineate conditions under which such a universal constructor can be designed to operate dterministically and probabilistically.

Pati, A K; Pati, Arun K.; Braunstein, Samuel L.

2003-01-01T23:59:59.000Z

60

Quantum mechanical Universal constructor  

E-Print Network (OSTI)

Arbitrary quantum states cannot be copied. In fact, to make a copy we must provide complete information about the system. However, can a quantum system self-replicate? This is not answered by the no-cloning theorem. In the classical context, Von Neumann showed that a `universal constructor' can exist which can self-replicate an arbitrary system, provided that it had access to instructions for making copy of the system. We question the existence of a universal constructor that may allow for the self-replication of an arbitrary quantum system. We prove that there is no deterministic universal quantum constructor which can operate with finite resources. Further, we delineate conditions under which such a universal constructor can be designed to operate dterministically and probabilistically.

Arun K. Pati; Samuel L. Braunstein

2003-03-19T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Efficient classical simulation of the approximate quantum Fourier transform  

E-Print Network (OSTI)

We present a method for classically simulating quantum circuits based on the tensor contraction model of Markov and Shi (quant-ph/0511069). Using this method we are able to classically simulate the approximate quantum Fourier transform in polynomial time. Moreover, our approach allows us to formulate a condition for the composability of simulable quantum circuits. We use this condition to show that any circuit composed of a constant number of approximate quantum Fourier transform circuits and log-depth circuits with limited interaction range can also be efficiently simulated.

Nadav Yoran; Anthony J. Short

2006-11-23T23:59:59.000Z

62

Quantum Mechanics Without Observers  

E-Print Network (OSTI)

The measurement problem and the role of observers have plagued quantum mechanics since its conception. Attempts to resolve these have introduced anthropomorphic or non-realist notions into physics. A shift of perspective based upon process theory and utilizing methods from combinatorial games, interpolation theory and complex systems theory results in a novel realist version of quantum mechanics incorporating quasi-local, nondeterministic hidden variables that are compatible with the no-hidden variable theorems and relativistic invariance, and reproduce the standard results of quantum mechanics to a high degree of accuracy without invoking observers.

W. H. Sulis

2013-02-18T23:59:59.000Z

63

Is quantum mechanics exact?  

SciTech Connect

We formulate physically motivated axioms for a physical theory which for systems with a finite number of degrees of freedom uniquely lead to quantum mechanics as the only nontrivial consistent theory. Complex numbers and the existence of the Planck constant common to all systems arise naturally in this approach. The axioms are divided into two groups covering kinematics and basic measurement theory, respectively. We show that even if the second group of axioms is dropped, there are no deformations of quantum mechanics which preserve the kinematic axioms. Thus, any theory going beyond quantum mechanics must represent a radical departure from the usual a priori assumptions about the laws of nature.

Kapustin, Anton [California Institute of Technology, Pasadena, California 91125 (United States)] [California Institute of Technology, Pasadena, California 91125 (United States)

2013-06-15T23:59:59.000Z

64

Quantum Mechanics and Black Holes  

E-Print Network (OSTI)

This paper discusses the existence of black holes from the foundations of quantum mechanics. It is found that quantum mechanics rule out a possible gravitational collapse.

Jose N. Pecina-Cruz

2005-11-11T23:59:59.000Z

65

Fractals and quantum mechanics  

Science Conference Proceedings (OSTI)

A new application of a fractal concept to quantum physics has been developed. The fractional path integrals over the paths of the Lévy flights are defined. It is shown that if fractality of the Brownian trajectories leads to standard quantum mechanics

Nick Laskin

2000-01-01T23:59:59.000Z

66

Application of Ab-Initio Quantum and Classical Molecular Dynamics...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ab-Initio Quantum and Classical Molecular Dynamics Simulations to Study Clustered DNA Damage J.H. Miller 1 , M.B. Ernst 2 , M. Haranczyh 3 , L. Douali 2 , M. Gutowski 2 , and...

67

The classical capacity of quantum channels with memory  

E-Print Network (OSTI)

We investigate the classical capacity of two quantum channels with memory: a periodic channel with depolarizing channel branches, and a convex combination of depolarizing channels. We prove that the capacity is additive in both cases. As a result, the channel capacity is achieved without the use of entangled input states. In the case of a convex combination of depolarizing channels the proof provided can be extended to other quantum channels whose classical capacity has been proved to be additive in the memoryless case.

Tony Dorlas; Ciara Morgan

2009-02-17T23:59:59.000Z

68

The classical capacity of quantum channels with memory  

E-Print Network (OSTI)

We investigate the classical capacity of two quantum channels with memory: a periodic channel with depolarizing channel branches, and a convex combination of depolarizing channels. We prove that the capacity is additive in both cases. As a result, the channel capacity is achieved without the use of entangled input states. In the case of a convex combination of depolarizing channels the proof provided can be extended to other quantum channels whose classical capacity has been proved to be additive in the memoryless case.

Dorlas, Tony

2009-01-01T23:59:59.000Z

69

Probable Inference and Quantum Mechanics  

SciTech Connect

In its current very successful interpretation the quantum theory is fundamentally statistical in nature. Although commonly viewed as a probability amplitude whose (complex) square is a probability, the wavefunction or state vector continues to defy consensus as to its exact meaning, primarily because it is not a physical observable. Rather than approach this problem directly, it is suggested that it is first necessary to clarify the precise role of probability theory in quantum mechanics, either as applied to, or as an intrinsic part of the quantum theory. When all is said and done the unsurprising conclusion is that quantum mechanics does not constitute a logic and probability unto itself, but adheres to the long-established rules of classical probability theory while providing a means within itself for calculating the relevant probabilities. In addition, the wavefunction is seen to be a description of the quantum state assigned by an observer based on definite information, such that the same state must be assigned by any other observer based on the same information, in much the same way that probabilities are assigned.

Grandy, W. T. Jr. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82070 (United States)

2009-12-08T23:59:59.000Z

70

A Quantum Mechanical Travelling Salesman  

E-Print Network (OSTI)

A quantum simulation of a travelling salesman is described. A vector space for a graph is defined together with a sequence of operators which transform a special initial state into a superposition states representing Hamiltonian tours. The quantum amplitude for any tour is a function of the classical cost of travelling along the edges in that tour. Tours with the largest quantum amplitude may be different than those with the smallest classically-computed cost.

Ravindra N. Rao

2011-08-23T23:59:59.000Z

71

Quantum Mind from a Classical Field Theory of the Brain  

E-Print Network (OSTI)

We suggest that, with regard to a theory of quantum mind, brain processes can be described by a classical, dissipative, non-abelian gauge theory. In fact, such a theory has a hidden quantum nature due to its non-abelian character, which is revealed through dissipation, when the theory reduces to a quantum vacuum, where temperatures are of the order of absolute zero, and coherence of quantum states is preserved. We consider in particular the case of pure SU(2) gauge theory with a special anzatz for the gauge field, which breaks Lorentz invariance. In the ansatz, a contraction mapping plays the role of dissipation. In the limit of maximal dissipation, which corresponds to the attractive fixed point of the contraction mapping, the gauge fields reduce, up to constant factors, to the Pauli quantum gates for one-qubit states. Then tubuline-qubits can be processed in the quantum vacuum of the classical field theory of the brain, where decoherence is avoided due to the extremely low temperature. Finally, we interpret the classical SU(2) dissipative gauge theory as the quantum metalanguage (relative to the quantum logic of qubits), which holds the non-algorithmic aspect of the mind.

Paola Zizzi

2011-04-13T23:59:59.000Z

72

Quantum plasma effects in the classical regime  

E-Print Network (OSTI)

For quantum effects to be significant in plasmas it is often assumed that the temperature over density ratio must be small. In this paper we challenge this assumption by considering the contribution to the dynamics from the electron spin properties. As a starting point we consider a multicomponent plasma model, where electrons with spin up and spin down are regarded as different fluids. By studying the propagation of Alfv\\'{e}n wave solitons we demonstrate that quantum effects can survive in a relatively high-temperature plasma. The consequences of our results are discussed.

G. Brodin; M. Marklund; G. Manfredi

2008-02-01T23:59:59.000Z

73

A new introductory quantum mechanics curriculum  

E-Print Network (OSTI)

The Institute of Physics New Quantum Curriculum consists of freely available online learning and teaching materials (quantumphysics.iop.org) for a first course in university quantum mechanics starting from two-level systems. This approach immediately immerses students in inherently quantum mechanical aspects by focusing on experiments that have no classical explanation. It allows from the start a discussion of interpretive aspects of quantum mechanics and quantum information theory. This article gives an overview of the resources available at the IOP website. The core text is presented as around 80 articles co-authored by leading experts that are arranged in themes and can be used flexibly to provide a range of alternative approaches. Many of the articles include interactive simulations with accompanying activities and problem sets that can be explored by students to enhance their understanding. Much of the linear algebra needed for this approach is part of the resource. Solutions to activities are available ...

Kohnle, Antje; Browne, Dan; Everitt, Mark; Fomins, Aleksejs; Kok, Pieter; Kulaitis, Gytis; Prokopas, Martynas; Raine, Derek; Swinbank, Elizabeth

2013-01-01T23:59:59.000Z

74

Hydrogen atom as a quantum-classical hybrid system  

E-Print Network (OSTI)

Hydrogen atom is studied as a quantum-classical hybrid system, where the proton is treated as a classical object while the electron is regarded as a quantum object. We use a well known mean-field approach to describe this hybrid hydrogen atom; the resulting dynamics for the electron and the proton is compared to their full quantum dynamics. The electron dynamics in the hybrid description is found to be only marginally different from its full quantum counterpart. The situation is very different for the proton: in the hybrid description, the proton behaves like a free particle; in the fully quantum description, the wave packet center of the proton orbits around the center of mass. Furthermore, we find that the failure to describe the proton dynamics properly can be regarded as a manifestation of the fact that there is no conservation of momentum in the mean-field hybrid approach. We expect that such a failure is a common feature for all existing approaches for quantum-classical hybrid systems of Born-Oppenheimer type.

Fei Zhan; Biao Wu

2013-02-07T23:59:59.000Z

75

TRANSIENT QUANTUM MECHANICAL PROCESSES  

SciTech Connect

Our principal objective has centered on the development of sophisticated computational techniques to solve the time-dependent Schroedinger equation that governs the evolution of quantum mechanical systems. We have perfected two complementary methods, discrete variable representation and real space product formula, that show great promise in solving these complicated temporal problems. We have applied these methods to the interaction of laser light with molecules with the intent of not only investigating the basic mechanisms but also devising schemes for actually controlling the outcome of microscopic processes. Lasers now exist that produce pulses of such short duration as to probe a molecular process many times within its characteristic period--allowing the actual observation of an evolving quantum mechanical system. We have studied the potassium dimer as an example and found agreement with experimental changes in the intermediate state populations as a function of laser frequency--a simple control prescription. We have also employed elaborate quantum chemistry programs to improve the accuracy of basic input such as bound-bound and bound-free coupling moments. These techniques have far-ranging applicability; for example, to trapped quantum systems at very low temperatures such as Bose-Einstein condensates.

L. COLLINS; J. KRESS; R. WALKER

1999-07-01T23:59:59.000Z

76

On Randomness in Quantum Mechanics  

E-Print Network (OSTI)

The quantum mechanical probability densities are compared with the probability densities treated by the theory of random variables. The relevance of their difference for the interpretation of quantum mechanics is commented.

Alberto C. de la Torre

2007-07-19T23:59:59.000Z

77

MATHEMATICS 428/609D Mathematical Classical Mechanics  

E-Print Network (OSTI)

MATHEMATICS 428/609D Mathematical Classical Mechanics This course is intended to complement physics department classical mechanics courses in the sense that the physical background will be developed experience with rigorous mathematics (like Math 320 and 321) and with classical mechanics (like Physics 206

Feldman, Joel

78

CLASSICAL MECHANICS: THE THREE-BODY PROBLEM ZI CHONG KAO  

E-Print Network (OSTI)

CLASSICAL MECHANICS: THE THREE-BODY PROBLEM ZI CHONG KAO Abstract. The Three-Body Problem is one of the oldest unsolved problems of classical mechanics. It arose as a natural extension of the Two-Body Prob of numerous techniques in classical mechan- ics as well as dynamical systems. Understanding the Three

May, J. Peter

79

Kinetic Isotope Effects from Hybrid Classical and Quantum  

E-Print Network (OSTI)

-order perturbation (KP2) is sufficiently accurate for chemical applications.7 We describe an automated, numerical in chemical applications to determine KIEs for chemical reactions, and because of its fast convergenceCHAPTER 5 Kinetic Isotope Effects from Hybrid Classical and Quantum Path Integral Computations

Minnesota, University of

80

Inverting quantum decoherence by classical feedback from the environment  

E-Print Network (OSTI)

We show that for qubits and qutrits it is always possible to perfectly recover quantum coherence by performing a measurement only on the environment, whereas for dimension d>3 there are situations where recovery is impossible, even with complete access to the environment. For qubits, the minimal amount of classical information to be extracted from the environment equals the entropy exchange.

Francesco Buscemi; Giulio Chiribella; Giacomo Mauro D'Ariano

2005-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Some topics in thermodynamics and quantum mechanics  

E-Print Network (OSTI)

We sketch some connecting relations involving fractional and quantum calculi, fractal structure, thermodynamics, and quantum mechanics.

Robert Carroll

2012-10-29T23:59:59.000Z

82

Quantum Mechanics and Representation Theory Columbia University  

E-Print Network (OSTI)

Quantum Mechanics and Representation Theory Peter Woit Columbia University Texas Tech, November 21 2013 Peter Woit (Columbia University) Quantum Mechanics and Representation Theory November 2013 1 / 30 #12;Does Anyone Understand Quantum Mechanics? "No One Understands Quantum Mechanics" "I think

Woit, Peter

83

Quantum mechanics as "space-time statistical mechanics"?  

E-Print Network (OSTI)

In this paper we discuss and analyse the idea of trying to see (non-relativistic) quantum mechanics as a ``space-time statistical mechanics'', by using the classical statistical mechanical method on objective microscopic space-time configurations. It is argued that this could perhaps be accomplished by giving up the assumption that the objective ``state'' of a system is independent of a future measurement performed on the system. This idea is then applied in an example of quantum state estimation on a qubit system.

Anders Månsson

2005-01-24T23:59:59.000Z

84

Constructing quantum dynamics from mixed quantum-classical descriptions  

E-Print Network (OSTI)

at Austin, 1 University Station A5300, Austin, TX 78712-1167, USA Received 16 June 2003; accepted 29 August a zero point energy contribution. This quantum rate can be modewise factorized exactly into a product nature of a harmonic bath is zero point energy [6,7]. At low tem- perature, the lowest excited states

Barsegov, Valeri

85

System-reservoir dynamics of quantum and classical correlations  

Science Conference Proceedings (OSTI)

We examine the system-reservoir dynamics of classical and quantum correlations in the decoherence phenomenon within a two-qubit composite system interacting with two independent environments. The most common noise channels (amplitude damping, phase damping, bit flip, bit-phase flip, and phase flip) are analyzed. By analytical and numerical analyses we find that, contrary to what is usually stated in the literature, decoherence may occur without entanglement between the system and the environment. We also show that, in some cases, the bipartite quantum correlation initially present in the system is completely evaporated and not transferred to the environments.

Maziero, J.; Celeri, L. C.; Serra, R. M. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, R. Santa Adelia 166, 09210-170, Santo Andre, Sao Paulo (Brazil); Werlang, T. [Departamento de Fisica, Universidade Federal de Sao Carlos, Post Office Box 676, 13565-905, Sao Carlos, Sao Paulo (Brazil); Fanchini, F. F. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Post Office Box 6165, 13083-970, Campinas, Sao Paulo (Brazil)

2010-02-15T23:59:59.000Z

86

Quantum chaos in the nuclear collective model: I. Classical-quantum correspondence  

E-Print Network (OSTI)

Spectra of the geometric collective model of atomic nuclei are analyzed to identify chaotic correlations among nonrotational states. The model has been previously shown to exhibit a high degree of variability of regular and chaotic classical features with energy and control parameters. Corresponding signatures are now verified also on the quantum level for different schemes of quantization and with a variable classicality constant.

Pavel Stransky; Petr Hruska; Pavel Cejnar

2009-02-23T23:59:59.000Z

87

Quantum Gibbs distribution from dynamical thermalization in classical nonlinear lattices  

E-Print Network (OSTI)

We study numerically time evolution in classical lattices with weak or moderate nonlinearity which leads to interactions between linear modes. Our results show that in a certain strength range a moderate nonlinearity generates a dynamical thermalization process which drives the system to the quantum Gibbs distribution of probabilities, or average oscillation amplitudes. The effective dynamical temperature of the lattice varies from large positive to large negative values depending on energy of initially excited modes. This quantum Gibbs distribution is drastically different from usually expected energy equipartition over linear modes corresponding to a regime of classical thermalization. Possible experimental observations of this dynamical thermalization are discussed for cold atoms in optical lattices, nonlinear photonic lattices and optical fiber arrays.

Leonardo Ermann; Dima L. Shepelyansky

2013-07-22T23:59:59.000Z

88

Direct Detection of Classically Undetectable Dark Matter through Quantum Decoherence  

E-Print Network (OSTI)

Although various pieces of indirect evidence about the nature of dark matter have been collected, its direct detection has eluded experimental searches despite extensive effort. If the mass of dark matter is below 1 MeV, it is essentially imperceptible to conventional detection methods because negligible energy is transferred to nuclei during collisions. Here I propose directly detecting dark matter through the quantum decoherence it causes rather than its classical effects such as recoil or ionization. I show that quantum spatial superpositions are sensitive to low-mass dark matter which is inaccessible to classical techniques. This provides new independent motivation for matter interferometry with large masses, especially on spaceborne platforms. The apparent dark matter wind we experience as the Sun travels through the Milky Way ensures interferometers and related devices are directional detectors, and so are able to provide unmistakable evidence that decoherence has galactic origins.

C. Jess Riedel

2012-12-13T23:59:59.000Z

89

Classical capacity of quantum channels with general Markovian correlated noise  

E-Print Network (OSTI)

The classical capacity of a quantum channel with arbitrary Markovian correlated noise is evaluated. For the general case of a channel with long-term memory, which corresponds to a Markov chain which does not converge to equilibrium, the capacity is expressed in terms of the communicating classes of the Markov chain. For an irreducible and aperiodic Markov chain, the channel is forgetful, and one retrieves the known expression for the capacity.

Nilanjana Datta; Tony Dorlas

2007-12-05T23:59:59.000Z

90

Does Quantum Mechanics Make Sense?Does Quantum Mechanics Make Sense? Some relatively simple concepts show why the answer is yes.Some relatively simple concepts show why the answer is yes.  

E-Print Network (OSTI)

Does Quantum Mechanics Make Sense?Does Quantum Mechanics Make Sense? Some relatively simple Classical Mechanics Quantum Mechanics Relative Absolute What does relative vs. absolute size mean?What does relative vs. absolute size mean? Why does it matter?Why does it matter? #12;Classical Mechanics

Fayer, Michael D.

91

Theory of classical and quantum frustration in quantum many-body systems  

E-Print Network (OSTI)

We present a general scheme for the study of frustration in quantum systems. After introducing a universal measure of frustration for arbitrary quantum systems, we derive for it an exact inequality in terms of a class of entanglement monotones. We then state sufficient conditions for the ground states of quantum spin systems to saturate the inequality and confirm them with extensive numerical tests. These conditions provide a generalization to the quantum domain of the Toulouse criteria for classical frustration-free systems and establish a unified framework for studying the intertwining of geometric and quantum contributions to frustration.

Giampaolo, S M; Monras, A; Illuminati, F

2011-01-01T23:59:59.000Z

92

Emergence of Quantum Mechanics from a Sub-Quantum Statistical Mechanics  

E-Print Network (OSTI)

A research program within the scope of theories on "Emergent Quantum Mechanics" is presented, which has gained some momentum in recent years. Via the modeling of a quantum system as a non-equilibrium steady-state maintained by a permanent throughput of energy from the zero-point vacuum, the quantum is considered as an emergent system. We implement a specific "bouncer-walker" model in the context of an assumed sub-quantum statistical physics, in analogy to the results of experiments by Couder's group on a classical wave-particle duality. We can thus give an explanation of various quantum mechanical features and results on the basis of a "21st century classical physics", such as the appearance of Planck's constant, the Schr\\"odinger equation, etc. An essential result is given by the proof that averaged particle trajectories' behaviors correspond to a specific type of anomalous diffusion termed "ballistic" diffusion on a sub-quantum level. It is further demonstrated both analytically and with the aid of computer simulations that our model provides explanations for various quantum effects such as double-slit or n-slit interference. We show the averaged trajectories emerging from our model to be identical to Bohmian trajectories, albeit without the need to invoke complex wave functions or any other quantum mechanical tool. Finally, the model provides new insights into the origins of entanglement, and, in particular, into the phenomenon of a "systemic" nonlocality.

Gerhard Groessing

2013-04-12T23:59:59.000Z

93

Tampering detection system using quantum-mechanical systems  

DOE Patents (OSTI)

The use of quantum-mechanically entangled photons for monitoring the integrity of a physical border or a communication link is described. The no-cloning principle of quantum information science is used as protection against an intruder's ability to spoof a sensor receiver using a `classical` intercept-resend attack. Correlated measurement outcomes from polarization-entangled photons are used to protect against quantum intercept-resend attacks, i.e., attacks using quantum teleportation.

Humble, Travis S. (Knoxville, TN); Bennink, Ryan S. (Knoxville, TN); Grice, Warren P. (Oak Ridge, TN)

2011-12-13T23:59:59.000Z

94

129 Lecture Notes Relativistic Quantum Mechanics  

E-Print Network (OSTI)

129 Lecture Notes Relativistic Quantum Mechanics 1 Need for Relativistic Quantum Mechanics's equation of motion in mechanics. The initial condtions to solve the Newton's equation of motion

Murayama, Hitoshi

95

On a New Form of Quantum Mechanics  

E-Print Network (OSTI)

We propose a new form of nonrelativistic quantum mechanics which is based on a quantum version of the action principle.

N. N. Gorobey; A. S. Lukyanenko

2008-07-22T23:59:59.000Z

96

Quantum information in a nutshell () Quantum mechanics + information science  

E-Print Network (OSTI)

Quantum information in a nutshell (�²¤¶) Quantum mechanics + information science = quantum information science = quantum information transfer + quantum algorithm (software) + quantum computer (hardware) + quantum simulation +... = a field rapidly growing in the last 10 years ®v½d¤j¾�ª«²z¨t ±i©ú-õ #12;Brief

Chang, Ming-Che

97

Decoherence without classicality in the resonant quantum kicked rotor  

E-Print Network (OSTI)

We study the quantum kicked rotor in resonance subjected to an unitary noise defined through Kraus operators, we show that this type of decoherence does not, in general, lead to the classical diffusive behavior. We find exact analytical expressions for the density matrix and the variance in the primary resonances. The variance does not loose its ballistic behavior, however the coherence decays as a power law. The secondary resonances are treated numerically, obtaining a power-law decay for the variance and an exponential law decay for the coherence.

A. Romanelli

2009-05-05T23:59:59.000Z

98

Classical information storage in an $n$-level quantum system  

E-Print Network (OSTI)

A game is played by a team of two --- say Alice and Bob --- in which the value of a random variable $x$ is revealed to Alice only, who cannot freely communicate with Bob. Instead, she is given a quantum $n$-level system, respectively a classical $n$-state system, which she can put in possession of Bob in any state she wishes. We evaluate how successfully they managed to store and recover the value of $x$ in the used system by requiring Bob to specify a value $z$ and giving a reward of value $ f(x,z)$ to the team. We show that whatever the probability distribution of $x$ and the reward function $f$ are, when using a quantum $n$-level system, the maximum expected reward obtainable with the best possible team strategy is equal to that obtainable with the use of a classical $n$-state system. The proof relies on mixed discriminants of positive matrices and --- perhaps surprisingly --- an application of the Supply--Demand Theorem for bipartite graphs. As a corollary, we get an infinite set of new, dimension dependent inequalities regarding positive operator valued measures and density operators on complex $n$-space.

Péter E. Frenkel; Mihály Weiner

2013-04-21T23:59:59.000Z

99

Is quantum mechanics based on an invariance principle?  

E-Print Network (OSTI)

Non-relativistic quantum mechanics for a free particle is shown to emerge from classical mechanics through an invariance principle under transformations that preserve the Heisenberg position-momentum inequality. These transformations are induced by isotropic space dilations. This invariance imposes a change in the laws of classical mechanics that exactly corresponds to the transition to quantum mechanics. The Schroedinger equation appears jointly with a second nonlinear equation describing non-unitary processes. Unitary and non-unitary evolutions are exclusive and appear sequentially in time. The non-unitary equation admits solutions that seem to correspond to the collapse of the wave function.

Leon Brenig

2006-10-27T23:59:59.000Z

100

Scattering Relativity in Quantum Mechanics  

E-Print Network (OSTI)

Transforming from one reference frame to another yields an equivalent physical description. If quantum fields are transformed one way and quantum states transformed a different way then the physics changes. We show how to use the resulting changed physical description to obtain the equations of motion of charged, massive particles in electromagnetic and gravitational fields. The derivation is based entirely on special relativity and quantum mechanics.

Richard Shurtleff

2011-08-09T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Communication: Quantum mechanics without wavefunctions  

SciTech Connect

We present a self-contained formulation of spin-free non-relativistic quantum mechanics that makes no use of wavefunctions or complex amplitudes of any kind. Quantum states are represented as ensembles of real-valued quantum trajectories, obtained by extremizing an action and satisfying energy conservation. The theory applies for arbitrary configuration spaces and system dimensionalities. Various beneficial ramifications--theoretical, computational, and interpretational--are discussed.

Schiff, Jeremy [Department of Mathematics, Bar-Ilan University, Ramat Gan 52900 (Israel); Poirier, Bill [Department of Chemistry and Biochemistry, Texas Tech University, Box 41061, Lubbock, Texas 79409-1061 (United States) and Department of Physics, Texas Tech University, Box 41051, Lubbock, Texas 79409-1051 (United States)

2012-01-21T23:59:59.000Z

102

Student understanding of quantum mechanics  

Science Conference Proceedings (OSTI)

We investigate the difficulties of advanced undergraduate students toward the end of a full year upper-level quantum mechanics course with concepts related to quantum measurements and time development. Our analysis is based upon a test administered to 89 students from six universities and interviews with 9 students. Strikingly

Chandralekha Singh

2001-01-01T23:59:59.000Z

103

The Interpretation of Quantum Mechanics  

E-Print Network (OSTI)

In this paper, we demonstrate how the interpretation of quantum mechanics due to Land\\'e resolves the Schr\\"odinger cat paradox and disposes of the problem of wave function collapse.

H. V. Mweene

2004-11-09T23:59:59.000Z

104

Hyper-Hamiltonian quantum mechanics  

E-Print Network (OSTI)

We present a modification of quantum mechanics with a *possible worlds* semantics. It is shown that `gauge' degrees of freedom along possible worlds can be used to encode gravitational information.

Vladimir Trifonov

2006-03-02T23:59:59.000Z

105

Free will and quantum mechanics  

E-Print Network (OSTI)

A simple example is provided showing that violation of free will allows to reproduce the quantum mechanical predictions, and that the Clauser-Horne parameter can take the maximum value 4 for a proper choice.

Antonio Di Lorenzo

2011-05-05T23:59:59.000Z

106

Concept of Classical and Quantum Free Acoustic Field  

E-Print Network (OSTI)

The concept of classical and quantum free acoustic (FA) field is theoretically considered. The equations of the free acoustic field are derived. They coincide in the mathematical form with Maxwell equations for the free electromagnetic (EM) field. It is accentuated, that the equations in the mathematical form of Maxwell equations for the free EM-field are universal equations of the Nature. They describe any free complex-vector physical field, vector-functions of which are analytical functions. In the case of a free acoustic field, it seems to be the strong indication taking into account the quantum Fermi liquid model of EM-field leading to the existence of phonons, accompanying the process of a photon formation, that FA-field and free EM-field are the display of the single united field, both the components of which can propagate simultaneously [however, with different velocities], for instance, in weakly absorbing media. The theory proposed can be the theoretical basis for the practical realization of superconducting states at high temperature in the materials with the strong interaction of electrons with acoustic field phonons and with microwave photons in magnetic resonance conditions.

Dmitri Yerchuck; Felix Borovik; Alla Dovlatova; Andrey Alexandrov

2013-12-26T23:59:59.000Z

107

From Quantum Mechanics to String Theory  

E-Print Network (OSTI)

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics, 2009 #12;Quantum Mechanics: Measurement and Uncertainty Thursday, May 7, 2009 #12;Puzzle: The Stern it. Quantum mechanics understanding: the particle exists in a state without definite position

108

Graduate quantum mechanics reform  

Science Conference Proceedings (OSTI)

We address four main areas in which graduatequantum mechanics education can be improved: course content

L. D. Carr; S. B. McKagan

2009-01-01T23:59:59.000Z

109

Bohmian Mechanics and Quantum Information  

E-Print Network (OSTI)

Many recent results suggest that quantum theory is about information, and that quantum theory is best understood as arising from principles concerning information and information processing. At the same time, by far the simplest version of quantum mechanics, Bohmian mechanics, is concerned, not with information but with the behavior of an objective microscopic reality given by particles and their positions. What I would like to do here is to examine whether, and to what extent, the importance of information, observation, and the like in quantum theory can be understood from a Bohmian perspective. I would like to explore the hypothesis that the idea that information plays a special role in physics naturally emerges in a Bohmian universe.

Sheldon Goldstein

2009-07-14T23:59:59.000Z

110

Statistical Structures Underlying Quantum Mechanics and Social Science  

E-Print Network (OSTI)

Common observations of the unpredictability of human behavior and the influence of one question on the answer to another suggest social science experiments are probabilistic and may be mutually incompatible with one another, characteristics attributed to quantum mechanics (as distinguished from classical mechanics). This paper examines this superficial similarity in depth using the Foulis-Randall Operational Statistics language. In contradistinction to physics, social science deals with complex, open systems for which the set of possible experiments is unknowable and outcome interference is a graded phenomenon resulting from the ways the human brain processes information. It is concluded that social science is, in some ways, "less classical" than quantum mechanics, but that generalized "quantum" structures may provide appropriate descriptions of social science experiments. Specific challenges to extending "quantum" structures to social science are identified.

Ron Wright

2003-07-30T23:59:59.000Z

111

Nano-wires with surface disorder: Giant localization lengths and quantum-to-classical crossover  

E-Print Network (OSTI)

We investigate electronic quantum transport through nano-wires with one-sided surface roughness. A magnetic field perpendicular to the scattering region is shown to lead to exponentially diverging localization lengths in the quantum-to-classical crossover regime. This effect can be quantitatively accounted for by tunneling between the regular and the chaotic components of the underlying mixed classical phase space.

J. Feist; A. Bäcker; R. Ketzmerick; S. Rotter; B. Huckestein; J. Burgdörfer

2006-06-22T23:59:59.000Z

112

Quantum Statistical Mechanics and Quantum Computation Thursday, 22 March 2012  

E-Print Network (OSTI)

Quantum Statistical Mechanics and Quantum Computation Thursday, 22 March 2012 8:50 am Welcoming:30 ­ 5:30 "Criticality without frustration for quantum spin-1 chains" Sergey Bravyi 6:30 pm Dinner at Triumph Brewery 138 Nassau Street Princeton, NJ 08542 609-924-7855 Quantum Statistical Mechanics

113

Efficient Energy Transfer in Light-Harvesting Systems, II: Quantum-Classical Comparison, Flux Network, and Robustness Analysis  

E-Print Network (OSTI)

Following the calculation of optimal energy transfer in thermal environment in our first paper (Wu et al., New J. Phys., 2010, 12, 105012), full quantum dynamics and leading-order `classical' hopping kinetics are compared in the seven-site Fenna-Matthews-Olson (FMO) protein complex. The difference between these two dynamic descriptions is due to higher-order quantum corrections. Two thermal bath models, classical white noise (the Haken-Strobl-Reineker model) and quantum Debye model, are considered. In the seven-site FMO model, we observe that higher-order corrections lead to negligible changes in the trapping time or in energy transfer efficiency around the optimal and physiological conditions (2% in the HSR model and 0.1% in the quantum Debye model for the initial site at BChl 1). However, using the concept of integrated flux, we can identify significant differences in branching probabilities of the energy transfer network between hopping kinetics and quantum dynamics (26% in the HSR model and 32% in the quantum Debye model for the initial site at BChl 1). This observation indicates that the quantum coherence can significantly change the distribution of energy transfer pathways in the flux network with the efficiency nearly the same. The quantum-classical comparison of the average trapping time with the removal of the bottleneck site, BChl 4, demonstrates the robustness of the efficient energy transfer by the mechanism of multi-site quantum coherence. To reconcile with the latest eight-site FMO model, the quantum-classical comparison with the flux network analysis is summarized in the appendix. The eight-site FMO model yields similar trapping time and network structure as the seven-site FMO model but leads to a more disperse distribution of energy transfer pathways.

Jianlan Wu; Fan Liu; Jian Ma; Robert J. Silbey; Jianshu Cao

2011-09-27T23:59:59.000Z

114

221B Lecture Notes Relativistic Quantum Mechanics  

E-Print Network (OSTI)

221B Lecture Notes Relativistic Quantum Mechanics 1 Need for Relativistic Quantum Mechanics We, similarly to the Newton's equation of motion in mechanics. The initial condtions to solve the Newton

Murayama, Hitoshi

115

221B Lecture Notes Relativistic Quantum Mechanics  

E-Print Network (OSTI)

221B Lecture Notes Relativistic Quantum Mechanics 1 Need for Relativistic Quantum Mechanics We's equation of motion in mechanics. The initial condtions to solve the Newton's equation of motion

Murayama, Hitoshi

116

THE OBJECTIVE INDEFINITENESS INTERPRETATION OF QUANTUM MECHANICS: Partition logic, logical information theory, and quantum mechanics  

E-Print Network (OSTI)

THE OBJECTIVE INDEFINITENESS INTERPRETATION OF QUANTUM MECHANICS: Partition logic, logical information theory, and quantum mechanics David Ellerman University of California at Riverside www ago that quantum mechanics was not compatible with Boolean logic, then the natural thing to do would

Wüthrich, Christian

117

System of classical nonlinear oscillators as a coarse-grained quantum system  

SciTech Connect

Constrained Hamiltonian dynamics of a quantum system of nonlinear oscillators is used to provide the mathematical formulation of a coarse-grained description of the quantum system. It is seen that the evolution of the coarse-grained system preserves constant and minimal quantum fluctuations of the fundamental observables. This leads to the emergence of the corresponding classical system on a sufficiently large scale.

Radonjc, Milan; Prvanovic, Slobodan; Buric, Nikola [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)

2011-08-15T23:59:59.000Z

118

Propagators in Nonrelativistic Quantum Mechanics  

Science Conference Proceedings (OSTI)

A discussion of propagators (Green's functions) and methods for calculating them for the simplest systems in nonrelativistic quantum mechanics is given from several points of view. The relevance of such techniques to partition function calculations is pointed out. Finally

Laurent A. Beauregard

1966-01-01T23:59:59.000Z

119

On quantum capacity of erasure channel assisted by back classical communication  

E-Print Network (OSTI)

We present a communication protocol for the erasure channel assisted by backward classical communication, which achieves a significantly better rate than the best prior result. In addition, we prove an upper bound for the capacity of the channel. The upper bound is smaller than the capacity of the erasure channel when it is assisted by two-way classical communication. Thus, we prove the separation between quantum capacities assisted by backward classical communication and two-way classical communication.

Debbie Leung; Joungkeun Lim; Peter Shor

2007-10-31T23:59:59.000Z

120

From Quantum Mechanics to String Theory  

E-Print Network (OSTI)

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics) New Particles anti-particles (combining special relativity and quantum mechanics pions (mediator mechanics, implies an infinite tower of negative energy states, rather than a ground state suppose

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

From Quantum Mechanics to String Theory  

E-Print Network (OSTI)

From Quantum Mechanics to String Theory Relativity (why it makes sense) Quantum mechanics Extra Dimensions Strings and the Strong Force Thursday, June 4, 2009 #12;The Higgs Mechanism Summary Mechanical Particle Physics General Relativistic Quantum Gravity increasing speed decreasing size increasing

122

Bohmian Trajectories as the Foundation of Quantum Mechanics  

E-Print Network (OSTI)

Bohmian trajectories have been used for various purposes, including the numerical simulation of the time-dependent Schroedinger equation and the visualization of time-dependent wave functions. We review the purpose they were invented for: to serve as the foundation of quantum mechanics, i.e., to explain quantum mechanics in terms of a theory that is free of paradoxes and allows an understanding that is as clear as that of classical mechanics. Indeed, they succeed in serving that purpose in the context of a theory known as Bohmian mechanics, to which this article is an introduction.

Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

2009-12-14T23:59:59.000Z

123

Star Products for Relativistic Quantum Mechanics  

E-Print Network (OSTI)

The star product formalism has proved to be an alternative formulation for nonrelativistic quantum mechanics. We want introduce here a covariant star product in order to extend the star product formalism to relativistic quantum mechanics in the proper time formulation.

P. Henselder

2007-05-24T23:59:59.000Z

124

Starting from Quantum Mechanics - Programmaster.org  

Science Conference Proceedings (OSTI)

Computational Modeling and Simulation of Advanced Materials for Energy Applications: Starting from Quantum Mechanics Sponsored by: TMS/ASM: ...

125

Information Nano-Technologies: Transition from Classical to Quantum  

E-Print Network (OSTI)

In this presentation are discussed some problems, relevant with application of information technologies in nano-scale systems and devices. Some methods already developed in quantum information technologies may be very useful here. Here are considered two illustrative models: representation of data by quantum bits and transfer of signals in quantum wires.

Vlasov, Alexander Yu

2009-01-01T23:59:59.000Z

126

Information Nano-Technologies: Transition from Classical to Quantum  

E-Print Network (OSTI)

In this presentation are discussed some problems, relevant with application of information technologies in nano-scale systems and devices. Some methods already developed in quantum information technologies may be very useful here. Here are considered two illustrative models: representation of data by quantum bits and transfer of signals in quantum wires.

Alexander Yu. Vlasov

2009-12-04T23:59:59.000Z

127

A Criterion for Holism in Quantum Mechanics  

E-Print Network (OSTI)

A Criterion for Holism in Quantum Mechanics M.P Seevinck E-mail: M.P.Seevinck@phys.uu.nl Utrecht University, The Netherlands, August 2003. 1 #12; Motivation · The question whether or not quantum mechanics is it that makes quantum mechanics a holistic theory (if so), and other physical theories not (if so). · I propose

Seevinck, Michiel

128

Probability in modal interpretations of quantum mechanics  

E-Print Network (OSTI)

Probability in modal interpretations of quantum mechanics Dennis Dieks Institute for the History interpretations have the ambition to construe quantum mechanics as an ob- jective, man-independent description of physical reality. Their second leading idea is probabilism: quantum mechanics does not completely fix

Seevinck, Michiel

129

Conceptual Development of Quantum Mechanics: Experiences with the Visual Quantum Mechanics Materials*  

E-Print Network (OSTI)

Conceptual Development of Quantum Mechanics: Experiences with the Visual Quantum Mechanics using a portion of the materials developed by the Visual Quantum Mechanics (VQM) project1 as part of our recent efforts to investigate student understanding of basic quantum mechanics concepts. The VQM

Larkin, Teresa L.

130

The H2 Double-Slit Experiment: Where Quantum and Classical Physics...  

NLE Websites -- All DOE Office Websites (Extended Search)

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print For the first time, an international research team carried out a double-slit experiment in H2, the...

131

Prequantum Classical Statistical Field Theory: Fundamentals  

SciTech Connect

We present fundamentals of a prequantum model with hidden variables of the classical field type. In some sense this is the comeback of classical wave mechanics. Our approach also can be considered as incorporation of quantum mechanics into classical signal theory. All quantum averages (including correlations of entangled systems) can be represented as classical signal averages and correlations.

Khrennikov, Andrei [International Center for Mathematical Modelling in Physics and Cognitive Sciences, Linnaeus University, Vaexjoe, S-35195 (Sweden)

2011-03-28T23:59:59.000Z

132

On reconciling quantum mechanics and local realism  

E-Print Network (OSTI)

A necessary and natural change in our application of quantum mechanics to separated systems is shown to reconcile quantum mechanics and local realism. An analysis of separation and localization justifies the proposed change in application of quantum mechanics. An important EPRB experiment is reconsidered and it is seen that when it is correctly interpreted it supports local realism. This reconciliation of quantum mechanics with local realism allows the axiom sets of quantum mechanics, probability, and special relativity to be joined in a consistent global axiom set for physics.

Donald A. Graft

2013-09-04T23:59:59.000Z

133

Quantization in classical mechanics and its relation to the Bohmian {Psi}-field  

SciTech Connect

Research highlights: > The Schroedinger equation is derived from the classical Hamiltonian mechanics. > This derivation is based on the Chetaev theorem on stable dynamical trajectories. > The conditions for correctness of trajectory quantum mechanics are discussed. - Abstract: Based on the Chetaev theorem on stable dynamical trajectories in the presence of dissipative forces, we obtain the generalized condition for stability of Hamilton systems in the form of the Schroedinger equation. It is shown that the energy of dissipative forces, which generate the Chetaev generalized condition of stability, coincides exactly with the Bohm 'quantum' potential. Within the frame-work of Bohmian quantum mechanics supplemented by the generalized Chetaev theorem and on the basis of the principle of least action for dissipative forces, we show that the squared amplitude of a wave function in the Schroedinger equation is equivalent semantically and syntactically to the probability density function for the number of particle trajectories, relative to which the velocity and the position of the particle are not hidden parameters. The conditions for the correctness of trajectory interpretation of quantum mechanics are discussed.

Rusov, V.D., E-mail: siiis@te.net.ua [Department of Theoretical and Experimental Nuclear Physics, Odessa National Polytechnic University, 65044 Odessa (Ukraine); Faculty of Mathematics, Bielefeld University, P.O.X: 100131, Bielefeld (Germany); Vlasenko, D.S. [Department of Theoretical and Experimental Nuclear Physics, Odessa National Polytechnic University, 65044 Odessa (Ukraine); Mavrodiev, S.Cht. [The Institute for Nuclear Research and Nuclear Energy, BAS, 1874 Sofia (Bulgaria); Joint Institute for Nuclear Research, Dubna (Russian Federation)

2011-08-15T23:59:59.000Z

134

Classical analogous of quantum cosmological perfect fluid models  

E-Print Network (OSTI)

Quantization in the mini-superspace of a gravity system coupled to a perfect fluid, leads to a solvable model which implies singularity free solutions through the construction of a superposition of the wavefunctions. We show that such models are equivalent to a classical system where, besides the perfect fluid, a repulsive fluid with an equation of state $p_Q = \\rho_Q$ is present. This leads to speculate on the true nature of this quantization procedure. A perturbative analysis of the classical system reveals the condition for the stability of the classical system in terms of the existence of an anti-gravity phase.

A. B. Batista; J. C. Fabris; S. V. B. Goncalves; J. Tossa

2000-11-28T23:59:59.000Z

135

Quantum Mechanics: Structures, Axioms and Paradoxes  

E-Print Network (OSTI)

Quantum Mechanics: Structures, Axioms and Paradoxes Diederik Aerts Center Leo Apostel, Brussels present an analysis of quantum mechanics and its problems and para- doxes taking into account the results that have been obtained during the last two decades by investigations in the field of `quantum structures re

Aerts, Diederik

136

Parrondo's paradox and superactivation of classical and quantum capacity of communication channels with memory  

E-Print Network (OSTI)

There exist memoryless zero-capacity quantum channels that when used jointly result in the channel with positive capacity. This phenomenon is called superactivation. Making use of Parrondo's paradox, we exhibit examples of superactivation-like effect for the capacity of classical communication channels as well as quantum and private capacity of quantum channels with memory. There are several ingredients necessary for superactivation of quantum capacity to occur in memoryless case. The first one is the requirement for the quantum channels which are amenable for superactivation to come from two distinct families - binding entanglement channels and erasure channels. The second one is the ability to utilize inputs which are entangled across the uses of the channels. Our construction uses a single family of erasure channels with classical memory to achieve the same superactivation-like effect for quantum capacity without any of the ingredients above.

Sergii Strelchuk

2013-05-06T23:59:59.000Z

137

Errors and paradoxes in quantum mechanics  

E-Print Network (OSTI)

Errors and paradoxes in quantum mechanics, entry in the Compendium of Quantum Physics: Concepts, Experiments, History and Philosophy, ed. F. Weinert, K. Hentschel, D. Greenberger and B. Falkenburg (Springer), to appear

D. Rohrlich

2007-08-28T23:59:59.000Z

138

Quantum Mechanics Joachim Burgdorfer and Stefan Rotter  

E-Print Network (OSTI)

1 1 Quantum Mechanics Joachim Burgd¨orfer and Stefan Rotter 1.1 Introduction 3 1.2 Particle and Quantization 8 1.5 Angular Momentum in Quantum Mechanics 9 1.6 Formalism of Quantum Mechanics 12 1.7 Solution 29 1.8.3 Resonances 30 1.9 Semiclassical Mechanics 31 1.9.1 The WKB Approximation 31 1.9.2 The EBK

Rotter, Stefan

139

Bohmian Mechanics with Complex Action: A New Trajectory-Based Formulation of Quantum Mechanics  

E-Print Network (OSTI)

In recent years there has been a resurgence of interest in Bohmian mechanics as a numerical tool because of its local dynamics, which suggest the possibility of significant computational advantages for the simulation of large quantum systems. However, closer inspection of the Bohmian formulation reveals that the nonlocality of quantum mechanics has not disappeared -- it has simply been swept under the rug into the quantum force. In this paper we present a new formulation of Bohmian mechanics in which the quantum action, S, is taken to be complex. This leads to a single equation for complex S, and ultimately complex x and p but there is a reward for this complexification -- a significantly higher degree of localization. The quantum force in the new approach vanishes for Gaussian wavepacket dynamics, and its effect on barrier tunneling processes is orders of magnitude lower than that of the classical force. We demonstrate tunneling probabilities that are in virtually perfect agreement with the exact quantum mechanics down to 10^{-7} calculated from strictly localized quantum trajectories that do not communicate with their neighbors. The new formulation may have significant implications for fundamental quantum mechanics, ranging from the interpretation of non-locality to measures of quantum complexity.

Yair Goldfarb; Ilan Degani; David J. Tannor

2006-04-20T23:59:59.000Z

140

Efficient energy transfer in light-harvesting systems: Quantum-classical comparison, flux network, and robustness analysis  

SciTech Connect

Following the calculation of optimal energy transfer in thermal environment in our first paper [J. L. Wu, F. Liu, Y. Shen, J. S. Cao, and R. J. Silbey, New J. Phys. 12, 105012 (2010)], full quantum dynamics and leading-order 'classical' hopping kinetics are compared in the seven-site Fenna-Matthews-Olson (FMO) protein complex. The difference between these two dynamic descriptions is due to higher-order quantum corrections. Two thermal bath models, classical white noise (the Haken-Strobl-Reineker (HSR) model) and quantum Debye model, are considered. In the seven-site FMO model, we observe that higher-order corrections lead to negligible changes in the trapping time or in energy transfer efficiency around the optimal and physiological conditions (2% in the HSR model and 0.1% in the quantum Debye model for the initial site at BChl 1). However, using the concept of integrated flux, we can identify significant differences in branching probabilities of the energy transfer network between hopping kinetics and quantum dynamics (26% in the HSR model and 32% in the quantum Debye model for the initial site at BChl 1). This observation indicates that the quantum coherence can significantly change the distribution of energy transfer pathways in the flux network with the efficiency nearly the same. The quantum-classical comparison of the average trapping time with the removal of the bottleneck site, BChl 4, demonstrates the robustness of the efficient energy transfer by the mechanism of multi-site quantum coherence. To reconcile with the latest eight-site FMO model which is also investigated in the third paper [J. Moix, J. L. Wu, P. F. Huo, D. F. Coker, and J. S. Cao, J. Phys. Chem. Lett. 2, 3045 (2011)], the quantum-classical comparison with the flux network analysis is summarized in Appendix C. The eight-site FMO model yields similar trapping time and network structure as the seven-site FMO model but leads to a more disperse distribution of energy transfer pathways.

Wu Jianlan [Physics Department, Zhejiang University, 38 ZheDa Road, Hangzhou, Zhejiang 310027 (China); Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States); Liu Fan; Silbey, Robert J.; Cao Jianshu [Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States); Ma Jian [Physics Department, Zhejiang University, 38 ZheDa Road, Hangzhou, Zhejiang 310027 (China)

2012-11-07T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

A Criterion for Holism in Quantum Mechanics  

E-Print Network (OSTI)

A Criterion for Holism in Quantum Mechanics M.P Seevinck Utrecht University, The Netherlands, June 2003. 1 #12; Motivation · The question whether or not quantum mechanics (QM) gives rise to some mechanics a holistic theory (if so), and other physical theories not (if so). · I propose an operational

Seevinck, Michiel

142

A Criterion for Holism in Quantum Mechanics  

E-Print Network (OSTI)

A Criterion for Holism in Quantum Mechanics # M.P Seevinck # # Utrecht University, The Netherlands, June 2003. # 1 #12; # Motivation # . The question whether or not quantum mechanics (QM) gives rise mechanics a holistic theory (if so), and other physical theories not (if so). . I propose an operational

Seevinck, Michiel

143

Quantum mechanical scoring for protein docking  

Science Conference Proceedings (OSTI)

We develop a docking protocol based on quantum mechanical/molecular mechanical calculations in which quantum mechanical energy is used as scoring. We test the protocol with three groups of examples with various binding site characteristics. The new docking method performs as well as or better than conventional docking methods in all three groups. In particular

Art E. Cho; Jae Yoon Chung

2009-01-01T23:59:59.000Z

144

Quantum Mechanics and Closed Timelike Curves  

E-Print Network (OSTI)

General relativity allows solutions exhibiting closed timelike curves. Time travel generates paradoxes and quantum mechanics generalizations were proposed to solve those paradoxes. The implications of self-consistent interactions on acausal region of space-time are investigated. If the correspondence principle is true, then all generalizations of quantum mechanics on acausal manifolds are not renormalizable. Therefore quantum mechanics can only be defined on global hyperbolic manifolds and all general relativity solutions exhibiting time travel are unphysical.

Florin Moldoveanu

2007-04-23T23:59:59.000Z

145

Bohmian particle trajectories contradict quantum mechanics  

E-Print Network (OSTI)

The Bohmian interpretation of quantum mechanics adds particle trajectories to the wave function and ensures that the probability distribution of the particle positions agrees with quantum mechanics at any time. This is not sufficient to avoid contradictions with quantum mechanics. There are correlations between particle positions at different times which cannot be reproduced with real particle trajectories. A simple rearrangement of an experimental test of the Bell-CHSH inequality demonstrates this.

Michael Zirpel

2009-03-23T23:59:59.000Z

146

Deformed Geometric Algebra and Supersymmetric Quantum Mechanics  

E-Print Network (OSTI)

Deforming the algebraic structure of geometric algebra on the phase space with a Moyal product leads naturally to supersymmetric quantum mechanics in the star product formalism.

Peter Henselder

2006-09-09T23:59:59.000Z

147

Integrated Quantum/Classical Modeling of Hydrogenic Materials  

DOE Green Energy (OSTI)

Path integral Monte Carlo simulations and calculations were performed on molecular hydrogen liquids. The equation-of-state, internal energies, and vapor liquid phase diagrams from simulation were found to be in quantitative agreement with experiments. Analytical calculations were performed on,H2 liquids using integral equation methods to study the degree of localization of the hydrogen molecules. Very little self-trapping or localization was found as a function of temperature and density. Good qualitative agreement was found between the integral equation calculations and the quantum Monte Carlo simulations for the radius of gyration of the hydrogen molecules. Path integral simulations were also performed on molecular hydrogen on graphite surfaces, slit pores, and in carbon nanotubes. Significant quantum effects on the adsorption of hydrogen were observed.

CURRO,JOHN G.; VAN SWOL,FRANK B.; FYE,RICHARD M.; WANG,Q.; JOHNSON,J.K.; PATRA,C.; YETHIRAJ,A.

1999-11-01T23:59:59.000Z

148

Scaling the RMG quantum mechanics code  

Science Conference Proceedings (OSTI)

In this paper, we describe parallelization and optimizations of the RMG quantum mechanics code to achieve scaling to over a hundred thousand cores. The parallelization uses a combination of message passing and threads. Further speedups have been attained ... Keywords: nanoscience, nanotechnology, performance analysis, quantum mechanics, scalability

Shirley Moore; Emil Briggs; Miroslav Hodak; Wenchang Lu; Jerry Bernholc; Chee-Wai Lee

2012-07-01T23:59:59.000Z

149

The Significance to Quantum Computing of the Classical Harmonic Nature of Energy Eigenstates  

E-Print Network (OSTI)

Since a pure quantum system is incapable of faithfully simulating the solutions of the Schroedinger equation that actually pertains to itself, it is proposed that quantum computing technology (as opposed to cryptographic technology) not be based on pure quantum systems such as qubits but instead on physical systems which by their nature faithfully simulate the solutions of Schroedinger equations. Every Schroedinger equation is within a unitary transformation of being a set of mutually independent classical simple harmonic oscillator equations. Thus classical simple harmonic oscillators, or "chobits", are the mathematically fundamental building blocks for all Schroedinger equations. In addition, classical harmonic oscillators are, as a practical matter, far easier to deal with than any pure quantum system -- e.g., their phases and absolute amplitudes are readily physically accessible, they have little predilection for environmental decoherence, and they abound as cavity electromagnetic standing-wave modes. We study in mathematical detail the use of chobits to compute discrete quantum Fourier transforms, including gates, chobit counts, and chobit operation counts. The results suggest that thirty chobits and under a thousand chobit phase operations could generate discrete quantum Fourier transforms of a billion terms. Chobits can be technologically realized as semiconductor dynatron-type electronic oscillator circuits, which ought to be amenable to very considerable miniaturization.

Steven Kenneth Kauffmann

2012-10-20T23:59:59.000Z

150

Using semiclassical trajectories for the time-evolution of interacting quantum-mechanical systems  

Science Conference Proceedings (OSTI)

We have developed a method that recasts the time-propagation of dynamic, mutually interacting quantum-mechanical wavefunctions principally as the time-evolution of many classical particles. Our approach utilizes an approximation of Feynman path integrals, ... Keywords: Feynman, WKB, grid method, interacting, lagrangian, parallel computation, particle-based, path integral, plasma PIC, quantum particle-in-cell, semiclassical, stationary phase, time evolving

D. E. Dauger; V. K. Decyk; J. M. Dawson

2005-11-01T23:59:59.000Z

151

Persistent entanglement in two coupled SQUID rings in the quantum to classical transition - A quantum jumps approach  

E-Print Network (OSTI)

We explore the quantum-classical crossover of two coupled, identical, superconducting quantum interference device (SQUID) rings. The motivation for this work is based on a series of recent papers. In ~[1] we showed that the entanglement characteristics of chaotic and periodic (entrained) solutions of the Duffing oscillator differed significantly and that in the classical limit entanglement was preserved only in the chaotic-like solutions. However, Duffing oscillators are a highly idealised toy system. Motivated by a wish to explore more experimentally realisable systems we extended our work in [2,3] to an analysis of SQUID rings. In [3] we showed that the two systems share a common feature. That is, when the SQUID ring's trajectories appear to follow (semi) classical orbits entanglement persists. Our analysis in[3] was restricted to the quantum state diffusion unravelling of the master equation - representing unit efficiency heterodyne detection (or ambi-quadrature homodyne detection). Here we show that very similar behaviour occurs using the quantum jumps unravelling of the master equation. Quantum jumps represents a discontinuous photon counting measurement process. Hence, the results presented here imply that such persistent entanglement is independent of measurement process and that our results may well be quite general in nature.

M. J. Everitt

2010-01-12T23:59:59.000Z

152

Strange Bedfellows: Quantum Mechanics and Data Mining  

SciTech Connect

Last year, in 2008, I gave a talk titled Quantum Calisthenics. This year I am going to tell you about how the work I described then has spun off into a most unlikely direction. What I am going to talk about is how one maps the problem of finding clusters in a given data set into a problem in quantum mechanics. I will then use the tricks I described to let quantum evolution lets the clusters come together on their own.

Weinstein, Marvin; /SLAC

2009-12-16T23:59:59.000Z

153

Nonadditivity of quantum and classical capacities for entanglement breaking multiple-access channels and the butterfly network  

Science Conference Proceedings (OSTI)

We analyze quantum network primitives which are entanglement breaking. We show superadditivity of quantum and classical capacity regions for quantum multiple-access channels and the quantum butterfly network. Since the effects are especially visible at high noise they suggest that quantum information effects may be particularly helpful in the case of the networks with occasional high noise rates. The present effects provide a qualitative borderline between superadditivities of bipartite and multipartite systems.

Grudka, Andrzej [Faculty of Physics, Adam Mickiewicz University, PL-61-614 Poznan (Poland); National Quantum Information Centre of Gdansk, PL-81-824 Sopot (Poland); Horodecki, Pawel [National Quantum Information Centre of Gdansk, PL-81-824 Sopot (Poland); Faculty of Applied Physics and Mathematics, Technical University of Gdansk, PL-80-952 Gdansk (Poland)

2010-06-15T23:59:59.000Z

154

Canonical distribution and incompleteness of quantum mechanics  

E-Print Network (OSTI)

The paper discusses the physical groundlessness of the models used for the derivation of canonical distribution and provides the experimental data demonstrating the incompleteness of quantum mechanics. The possibility of using statistical ensembles is presented as a consequence of the existence of probabilistic processes which are not accounted for by quantum mechanics. The paper provides a new analytical derivation of canonical distribution for macrosystems which takes into account subquantum processes. The paper discusses the possibility of the experimental study of a probability which is beyond quantum mechanics.

V. A. Skrebnev

2012-01-04T23:59:59.000Z

155

Four-dimensional understanding of quantum mechanics  

E-Print Network (OSTI)

In this paper I will try to convince that quantum mechanics does not have to lead to indeterminism, but is just a natural consequence of four-dimensional nature of our world - that for example particles shouldn't be imagined as 'moving points' in space, but as their trajectories in the spacetime like in optimizing action formulation of Lagrangian mechanics. There will be analyzed simplified model - Boltzmann distribution among trajectories occurs to give quantum mechanic like behavior - for example electron moving in proton's potential would make some concrete trajectory which average exactly to the probability distribution of the quantum mechanical ground state. We will use this model to build intuition about quantum mechanics and discuss its generalizations to get some effective approximation of physics. We will see that topological excitations of the simplest model obtained this way already creates known from physics particle structure, their decay modes and electromagnetic/gravitational interactions between them.

Jarek Duda

2009-10-14T23:59:59.000Z

156

Quantum Mechanics and the Generalized Uncertainty Principle  

E-Print Network (OSTI)

The generalized uncertainty principle has been described as a general consequence of incorporating a minimal length from a theory of quantum gravity. We consider a simple quantum mechanical model where the operator corresponding to position has discrete eigenvalues and show how the generalized uncertainty principle results for minimum uncertainty wave packets.

Jang Young Bang; Micheal S. Berger

2006-10-11T23:59:59.000Z

157

On a New Form of Quantum Mechanics (II)  

E-Print Network (OSTI)

The correspondence of a new form of quantum mechanics based on a quantum version of the action principle, which was proposed earlier [arXiv:0807.3508], with the ordinary quantum mechanics is established. New potentialities of the quantum action principle in the interpretation of quantum mechanics are considered.

N. Gorobey; A. Lukyanenko; I. Lukyanenko

2009-12-16T23:59:59.000Z

158

CLNS 96/1399 Peculiarities of Quantum Mechanics  

E-Print Network (OSTI)

CLNS 96/1399 Peculiarities of Quantum Mechanics: Origins and Meaning Yuri F. Orlov Floyd R. Newman, specifically quantum, features of quantum mechanics --- quan­ tum nonlocality, indeterminism, interference are quantum observables themselves and are represented in quantum mechanics by density matrices of pure states

159

Classical and quantum description of electron trapping during the Cherenkov beam instability in plasma  

SciTech Connect

A nonlinear quantum theory of the Cherenkov instability of a nonrelativistic monoenergetic electron beam in a cold plasma is constructed. It is shown that the instability of a low-density beam is almost purely quantum in nature and results from the emission of one quantum of a plasma wave-a plasmon-by the beam electrons. The number of emitted (and absorbed) plasmons increases with beam density, so, in the limit of high-density beams, the instability becomes a classical Cherenkov beam instability in plasma. Some analytic solutions and estimates are found, detailed numerical results are obtained, and the evolution of the quantum distribution function of the beam electrons in different regimes of the beam instability is investigated.

Bobylev, Yu. V.; Kuzelev, M. V. [Moscow State University (Russian Federation)

2010-11-15T23:59:59.000Z

160

Nonequilibrium quantum statistical mechanics and thermodynamics  

E-Print Network (OSTI)

The purpose of this work is to discuss recent progress in deriving the fundamental laws of thermodynamics (0th, 1st and 2nd-law) from nonequilibrium quantum statistical mechanics. Basic thermodynamic notions are clarified and different reversible and irreversible thermodynamic processes are studied from the point of view of quantum statistical mechanics. Special emphasis is put on new adiabatic theorems for steady states close to and far from equilibrium, and on investigating cyclic thermodynamic processes using an extension of Floquet theory.

Walid K. Abou Salem

2006-01-23T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Quantum Mechanics Summary/Review Spring 2009 Compton Lecture Series  

E-Print Network (OSTI)

Quantum Mechanics Summary/Review Spring 2009 Compton Lecture Series: From Quantum Mechanics one component at a time. · Planck's constant determines the scale at which quantum mechanical effects could get rid of quantum mechanical effects ­ The "wavelength" of particles given by h mv would all

162

A symmetrical theory of nonrelativistic quantum mechanics  

E-Print Network (OSTI)

This paper presents a new Symmetrical Theory (ST) of nonrelativistic quantum mechanics which postulates: quantum mechanics is a theory about complete experiments, not particles; a complete experiment is maximally described by a complex transition amplitude density; and this transition amplitude density never collapses. This new ST is compared to the Conventional Theory (CT) of nonrelativistic quantum mechanics for the analysis of a beam-splitter experiment. The ST makes several experimentally testable predictions that differ from the CT, which can be checked using existing technology. The ST also solves one part of the CT measurement problem, and resolves some of the paradoxes of the CT. This nonrelativistic ST is the low energy limit of a relativistic ST presented in an earlier paper \\cite{Heaney1}.

Michael B. Heaney

2013-10-20T23:59:59.000Z

163

Quantum mechanics in fractional and other anomalous spacetimes  

SciTech Connect

We formulate quantum mechanics in spacetimes with real-order fractional geometry and more general factorizable measures. In spacetimes where coordinates and momenta span the whole real line, Heisenberg's principle is proven and the wave-functions minimizing the uncertainty are found. In spite of the fact that ordinary time and spatial translations are broken and the dynamics is not unitary, the theory is in one-to-one correspondence with a unitary one, thus allowing us to employ standard tools of analysis. These features are illustrated in the examples of the free particle and the harmonic oscillator. While fractional (and the more general anomalous-spacetime) free models are formally indistinguishable from ordinary ones at the classical level, at the quantum level they differ both in the Hilbert space and for a topological term fixing the classical action in the path integral formulation. Thus, all non-unitarity in fractional quantum dynamics is encoded in a contribution depending only on the initial and final states.

Calcagni, Gianluca [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Muehlenberg 1, D-14476 Golm (Germany); Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Nardelli, Giuseppe [Dipartimento di Matematica e Fisica, Universita Cattolica, via Musei 41, 25121 Brescia (Italy); INFN Gruppo Collegato di Trento, Universita di Trento, 38100 Povo (Trento) (Italy); Scalisi, Marco [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Muehlenberg 1, D-14476 Golm (Germany); Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

2012-10-15T23:59:59.000Z

164

NONEQUILIBRIUM QUANTUM STATISTICAL MECHANICS AND THERMODYNAMICS ?  

E-Print Network (OSTI)

The purpose of this work is to discuss recent progress in deriving the fundamental laws of thermodynamics (0 th, 1 st and 2 nd-law) from nonequilibrium quantum statistical mechanics. Basic thermodynamic notions are clarified and different reversible and irreversible thermodynamic processes are studied from the point of view of quantum statistical mechanics. Special emphasis is put on new adiabatic theorems for steady states close to and far from equilibrium, and on investigating cyclic thermodynamic processes using an extension of Floquet theory. This work is based on the author’s doctoral thesis, ETH-Diss 16187.

Walid K. Abou Salem

2006-01-01T23:59:59.000Z

165

Surveying Students’ Understanding of Quantum Mechanics  

Science Conference Proceedings (OSTI)

Development of research?based multiple?choice tests about quantum mechanics is important for assessing students’ difficulties and for evaluating curricula and pedagogies that strive to reduce the difficulties. We explore the difficulties that the undergraduate and graduate students have with non?relativistic quantum mechanics of one particle in one spatial dimension. We developed a research?based conceptual multiple?choice survey that targets these issues to obtain information about the common difficulties and administered it to more than a hundred students from seven different institutions. The issues targeted in the survey include the set of possible wavefunctions

Chandralekha Singh; Guangtian Zhu

2010-01-01T23:59:59.000Z

166

Quantum mechanics of time travel through post-selected teleportation  

E-Print Network (OSTI)

This paper discusses the quantum mechanics of closed-timelike curves (CTCs) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based ...

Maccone, Lorenzo

167

Hamilton relativity group for noninertial states in quantum mechanics  

E-Print Network (OSTI)

Physical states in quantum mechanics are rays in a Hilbert space. Projective representations of a relativity group transform between the quantum physical states that are in the admissible class. The physical observables of position, time, energy and momentum are the Hermitian representation of the Weyl-Heisenberg algebra. We show that there is a consistency condition that requires the relativity group to be a subgroup of the group of automorphisms of the Weyl-Heisenberg algebra. This, together with the requirement of the invariance of classical time, results in the inhomogeneous Hamilton group that is the relativity group for noninertial frames in classical Hamilton's mechanics. The projective representation of a group is equivalent to unitary representations of its central extension. The central extension of the inhomogeneous Hamilton group and its corresponding Casimir invariants are computed. One of the Casimir invariants is a generalized spin that is invariant for noninertial states. It is the familiar inertial Galilean spin with additional terms that may be compared to noninertial experimental results.

Stephen G. Low

2007-10-18T23:59:59.000Z

168

Is Quantum Mechanics needed to explain consciousness ?  

E-Print Network (OSTI)

In this short comment to a recent contribution by E. Manousakis [1] it is argued that the reported agreement between the measured time evolution of conscious states during binocular rivalry and predictions derived from quantum mechanical formalisms does not require any direct effect of QM. The recursive consumption analysis process in the Ouroboros Model can yield the same behavior.

Knud Thomsen

2007-11-13T23:59:59.000Z

169

The Quantum State of Classical Matter II: Thermodynamic Equilibrium and Hydrodynamics  

E-Print Network (OSTI)

In the previous companion paper, we proposed a subclass of wavefunctions to describe macroscopic solids that resolved and extended the theory quantum measurement and gave a more specific treatment of quasiparticles. Here we extend these notions to thermalization of solids and gases and to gas state hydrodynamics. This gives a modification of the thermodynamic limit to justify the canonical averages for "typical wavefunctions" without the use of ensembles. The energetic cost of vorticity is contrasted in the classical and ultracold gas limits. From this perspective, we then examine the applicability of thermo and hydro to ultracold gases and compare with the implications of pure state evolution. We illustrate how the proposed quantum limits on viscosity could be reinterpreted in terms of Schr\\"{o}dinger induced evolution of the one-body density function but some history dependent measurable properties should still persist.

Clifford E Chafin

2013-09-04T23:59:59.000Z

170

On Quantum Mechanical Aspects of Microtubules  

E-Print Network (OSTI)

We discuss possible quantum mechanical aspects of MicroTubules (MT), based on recent developments in quantum physics.We focus on potential mechanisms for `energy-loss-free' transport along the microtubules, which could be considered as realizations of Fröhlich's ideas on the rôle of solitons for superconductivity and/or biological matter. By representing the MT arrangements as cavities, we present a novel scenario on the formation of macroscopic (or mesoscopic) quantum-coherent states, as a result of the (quantum-electromagnetic) interactions of the MT dimers with the surrounding molecules of the ordered water in the interior of the MT cylinders. We suggest specific experiments to test the above-conjectured quantum nature of the microtubular arrangements inside the cell. These experiments are similar in nature to those in atomic physics, used in the detection of the Rabi-Vacuum coupling between coherent cavity modes and atoms. Our conjecture is that a similar Rabi-Vacuum-splitting phenomenon occurs in the M...

Mavromatos, Nikolaos E

1997-01-01T23:59:59.000Z

171

On Quantum Mechanical Aspects of Microtubules  

E-Print Network (OSTI)

We discuss possible quantum mechanical aspects of MicroTubules (MT), based on recent developments in quantum physics.We focus on potential mechanisms for `energy-loss-free' transport along the microtubules, which could be considered as realizations of Fr\\"ohlich's ideas on the r\\^ole of solitons for superconductivity and/or biological matter. By representing the MT arrangements as cavities,we present a novel scenario on the formation of macroscopic (or mesoscopic) quantum-coherent states, as a result of the (quantum-electromagnetic) interactions of the MT dimers with the surrounding molecules of the ordered water in the interior of the MT cylinders. We suggest specific experiments to test the above-conjectured quantum nature of the microtubular arrangements inside the cell. These experiments are similar in nature to those in atomic physics, used in the detection of the Rabi-Vacuum coupling between coherent cavity modes and atoms. Our conjecture is that a similar Rabi-Vacuum-splitting phenomenon occurs in the MT case.

N. E. Mavromatos; D. V. Nanopoulos

1997-08-01T23:59:59.000Z

172

Quantum Histories and Quantum Gravity  

E-Print Network (OSTI)

This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.

Joe Henson

2009-01-26T23:59:59.000Z

173

Integral Transforms in Relativistic Quantum Constraint Mechanics  

E-Print Network (OSTI)

In relativistic quantum constraint mechanics the state of a physical system is constrained to a 3-dimensional subspace of Minkowski 4-space. Fourier transformation can be used to relate this state between constraint spaces in 4-position and 4-momentum space. It is shown that integral transforms of this nature can be carried out using Lorentz-invariant 3-dimensional constraint space coordinates such that a complete equivalence class of 4-space representations can be constructed from the transform. This method is further applied to develop a relativistic generalization of the Segal-Bargmann transformation that leads to the representation of quantum systems in a three-dimensional subspace of Bargmann 4-space.

Robert J. Ducharme

2011-01-29T23:59:59.000Z

174

A sequential Monte Carlo/Quantum Mechanics study of the dipole polarizability of liquid benzene  

Science Conference Proceedings (OSTI)

Metropolis Monte Carlo classical simulation and quantum mechanical calculations are performed to obtain the dipole polarizability of liquid benzene. Super-molecular configurations are sampled from NVT Monte Carlo simulation of liquid benzene at room ... Keywords: Monte Carlo simulation, density-functional theory, intermediate-neglect of differential overlap (INDO), liquid benzene, polarizability

Eudes E. Fileti; Sylvio Canuto

2004-12-01T23:59:59.000Z

175

Philosophy of Mind and the Problem of Free Will in the Light of Quantum Mechanics.  

E-Print Network (OSTI)

Foundations of Quantum Mechanics. (Princeton UniversityMind, Matter, and Quantum Mechanics, (Springer, Berlin & NewMindful Universe: Quantum Mechanics and the Participating

Stapp, Henry P

2008-01-01T23:59:59.000Z

176

PERTURBATION-THEORY RULES FOR COMPUTING THE SELF-ENERGY OPERATOR IN QUANTUM STATISTICAL MECHANICS  

E-Print Network (OSTI)

D. J. Thouless, The Quantum Mechanics of Many-Body Systems (1962). Ba~n, Quantum Statistical Mechanics (Benjamin, I. E.IN QUANTUM STATISTICAL MECHANICS Berkeley, California

Baym, Gordon

2008-01-01T23:59:59.000Z

177

The Particle Adventure | What holds it together? | Quantum mechanics  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum mechanics Quantum mechanics One of the surprises of modern science is that atoms and sub-atomic particles do not behave like anything we see in the everyday world. They are...

178

Quantum Mechanics Evaluation of Solid Oxide Fuel Cell Cathode ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Energy Conversion/Fuel Cells. Presentation Title, Quantum Mechanics ...

179

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet  

NLE Websites -- All DOE Office Websites (Extended Search)

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print For the first time, an international research team carried out a double-slit experiment in H2, the smallest and simplest molecule. Thomas Young's original experiment in 1803 passed light through two slits cut in a solid thin plate. In the groundbreaking experiment performed at ALS Beamlines 4.0 and 11.0.1, the researchers used electrons instead of light and the nuclei of the hydrogen molecule as the slits. The experiment revealed that only one "observing" electron suffices to induce the emergence of classical properties such as loss of coherence. Double photoionization of H2. Left: Circularly polarized light comes from the top. All angular distributions are in the plane perpendicular to the photon propagation vector: Φe-mol is the angle of the fast electron's trajectory to the molecular axis; Φe-e is the angle between both electron trajectories. Center: Photoionization by circularly polarized light launches a coherent spherical photoelectron wave at each nucleus of the molecule; the light propagates into the plane. Right: Measured electron angular distribution Φe-mol of the faster electron (E1) from double photoionization of H2 by circularly polarized light. The orientation of the molecule is horizontal. Light propagates into the plane of the figure, the molecule is fixed ±10° within the plane shown, Eϒ = 240 eV, and the energy of the slow electron E2 = 0 to 5 eV, resulting in E1 = 185 to 190 eV.

180

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet  

NLE Websites -- All DOE Office Websites (Extended Search)

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print For the first time, an international research team carried out a double-slit experiment in H2, the smallest and simplest molecule. Thomas Young's original experiment in 1803 passed light through two slits cut in a solid thin plate. In the groundbreaking experiment performed at ALS Beamlines 4.0 and 11.0.1, the researchers used electrons instead of light and the nuclei of the hydrogen molecule as the slits. The experiment revealed that only one "observing" electron suffices to induce the emergence of classical properties such as loss of coherence. Double photoionization of H2. Left: Circularly polarized light comes from the top. All angular distributions are in the plane perpendicular to the photon propagation vector: Φe-mol is the angle of the fast electron's trajectory to the molecular axis; Φe-e is the angle between both electron trajectories. Center: Photoionization by circularly polarized light launches a coherent spherical photoelectron wave at each nucleus of the molecule; the light propagates into the plane. Right: Measured electron angular distribution Φe-mol of the faster electron (E1) from double photoionization of H2 by circularly polarized light. The orientation of the molecule is horizontal. Light propagates into the plane of the figure, the molecule is fixed ±10° within the plane shown, Eϒ = 240 eV, and the energy of the slow electron E2 = 0 to 5 eV, resulting in E1 = 185 to 190 eV.

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While these samples are representative of the content of NLEBeta,
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181

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet  

NLE Websites -- All DOE Office Websites (Extended Search)

The H2 Double-Slit Experiment: The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print Wednesday, 27 February 2008 00:00 For the first time, an international research team carried out a double-slit experiment in H2, the smallest and simplest molecule. Thomas Young's original experiment in 1803 passed light through two slits cut in a solid thin plate. In the groundbreaking experiment performed at ALS Beamlines 4.0 and 11.0.1, the researchers used electrons instead of light and the nuclei of the hydrogen molecule as the slits. The experiment revealed that only one "observing" electron suffices to induce the emergence of classical properties such as loss of coherence. Double photoionization of H2. Left: Circularly polarized light comes from the top. All angular distributions are in the plane perpendicular to the photon propagation vector: Φe-mol is the angle of the fast electron's trajectory to the molecular axis; Φe-e is the angle between both electron trajectories. Center: Photoionization by circularly polarized light launches a coherent spherical photoelectron wave at each nucleus of the molecule; the light propagates into the plane. Right: Measured electron angular distribution Φe-mol of the faster electron (E1) from double photoionization of H2 by circularly polarized light. The orientation of the molecule is horizontal. Light propagates into the plane of the figure, the molecule is fixed ±10° within the plane shown, Eϒ = 240 eV, and the energy of the slow electron E2 = 0 to 5 eV, resulting in E1 = 185 to 190 eV.

182

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet  

NLE Websites -- All DOE Office Websites (Extended Search)

The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print The H2 Double-Slit Experiment: Where Quantum and Classical Physics Meet Print For the first time, an international research team carried out a double-slit experiment in H2, the smallest and simplest molecule. Thomas Young's original experiment in 1803 passed light through two slits cut in a solid thin plate. In the groundbreaking experiment performed at ALS Beamlines 4.0 and 11.0.1, the researchers used electrons instead of light and the nuclei of the hydrogen molecule as the slits. The experiment revealed that only one "observing" electron suffices to induce the emergence of classical properties such as loss of coherence. Double photoionization of H2. Left: Circularly polarized light comes from the top. All angular distributions are in the plane perpendicular to the photon propagation vector: Φe-mol is the angle of the fast electron's trajectory to the molecular axis; Φe-e is the angle between both electron trajectories. Center: Photoionization by circularly polarized light launches a coherent spherical photoelectron wave at each nucleus of the molecule; the light propagates into the plane. Right: Measured electron angular distribution Φe-mol of the faster electron (E1) from double photoionization of H2 by circularly polarized light. The orientation of the molecule is horizontal. Light propagates into the plane of the figure, the molecule is fixed ±10° within the plane shown, Eϒ = 240 eV, and the energy of the slow electron E2 = 0 to 5 eV, resulting in E1 = 185 to 190 eV.

183

Quantization in Classical Mechanics and Diffusion Mechanism of Alpha Decay, Proton and Cluster Radioactivity, Spontaneous Fission  

SciTech Connect

Based on the Chetaev generalized theorem the Schroedinger equation as the stability condition of trajectories in classical dynamics in the presence of dissipative forces is derived. In the framework of this approach the alternative model for unified description of alpha decay, spontaneous fission, cluster and proton radioactivity and is developed. We show the possibility of the classical (without tunneling) description of radioactive decay of heavy nuclei, when the so called noise-induced transition or, in other words, the stochastic channel of radioactive decay conditioned by the Kramers diffusion mechanism is generated under certain conditions.Using the ENSDF nuclear data, we have found the parametrized solutions of the Kramers equation of the Langevin type by the Alexandrov dynamic auto-regularization method (REGN-Dubna program). These solutions describe with high-accuracy the dependences of half-life (the decay probability) of heavy radioactive nuclei on total kinetic energy of daughter decay products.Verification of the inverse problem solution in the framework of the universal Kramers description of alpha decay, spontaneous fission, cluster and proton radioactivity, which based on the newest experimental data for alpha-decay of even-even superheavy nuclei (Z = 114, 116, 118), shows good coincidence of the experimental and theoretical dependences of half-life on alpha-decay energy.

Rusov, V. D.; Vlasenko, D. S.; Deliyergiyev, M. A. [Department of Theoretical and Experimental Nuclear Physics, Odessa National Polytechnic University, Odessa (Ukraine); Mavrodiev, S. Cht. [Institute for Nuclear Research and Nuclear Energy, BAS, Sofia (Bulgaria)

2010-01-01T23:59:59.000Z

184

Quantization in Classical Mechanics and Diffusion Mechanism of Alpha Decay, Cluster Radioactivity, Spontaneous Fission  

SciTech Connect

Based on the Chetaev generalized theorem the Schredinger equation as the stability condition of trajectories in classical dynamics in the presence of dissipative forces is derived. In the framework of this approach the alternative model for unified description of alpha decay, spontaneous fission, cluster radioactivity and is developed. We show the possibility of the classical (without tunneling) description of radioactive decay of heavy nuclei, when the so called noise-induced transition or, in other words, the stochastic channel of radioactive decay conditioned by the Kramers diffusion mechanism is generated under certain conditions.Using the ENSDF nuclear data, we have found the parametrized solutions of the Kramers equation of the Langevin type by the Alexandrov dynamic auto-regularization method (REGN-Dubna program). These solutions describe with high-accuracy the dependences of half-life (the decay probability) of heavy radioactive nuclei on total kinetic energy of daughter decay products.Verification of the inverse problem solution in the framework of the universal Kramers description of alpha decay, spontaneous fission, cluster radioactivity, which based on the newest experimental data for alpha-decay of even-even superheavy nuclei (Z = 114, 116, 118), shows good coincidence of the experimental and theoretical dependences of half-life on alpha-decay energy.

Rusov, V. D.; Vlasenko, D. S.; Deliyergiyev, M. A. [Department of Theoretical and Experimental Nuclear Physics, Odessa National Polytechnic University, Odessa (Ukraine); Mavrodiev, S. Cht. [Institute for Nuclear Research and Nuclear Energy, BAS, Sofia (Bulgaria)

2010-05-04T23:59:59.000Z

185

The Objective Inde...niteness Interpretation of Quantum Mechanics  

E-Print Network (OSTI)

The Objective Inde...niteness Interpretation of Quantum Mechanics David Ellerman University of California at Riverside Draft (not for quotation) May 28, 2013 Abstract Quantum mechanics (QM models indef- inite elements that become more de...nite as distinctions are made. If quantum mechanics

Wüthrich, Christian

186

Physical Interpretations of Nilpotent Quantum Mechanics  

E-Print Network (OSTI)

Nilpotent quantum mechanics provides a powerful method of making efficient calculations. More importantly, however, it provides insights into a number of fundamental physical problems through its use of a dual vector space and its explicit construction of vacuum. Physical interpretation of the nilpotent formalism is discussed with respect to boson and baryon structures, the mass-gap problem, zitterbewgung, Berry phase, renormalization, and related issues.

Peter Rowlands

2010-04-09T23:59:59.000Z

187

Avoiding Negative Probabilities in Quantum Mechanics  

E-Print Network (OSTI)

As currently understood since its discovery, the bare Klein-Gordon theory consists of negative quantum probabilities which are considered to be physically meaningless if not outright obsolete. Despite this annoying setback, these negative probabilities are what led the great Paul Dirac in 1928 to the esoteric discovery of the Dirac Equation. The Dirac Equation led to one of the greatest advances in our understanding of the physical world. In this reading, we ask the seemingly senseless question, "Do negative probabilities exist in quantum mechanics?" In an effort to answer this question, we arrive at the conclusion that depending on the choice one makes of the quantum probability current, one will obtain negative probabilities. We thus propose a new quantum probability current of the Klein-Gordon theory. This quantum probability current leads directly to positive definite quantum probabilities. Because these negative probabilities are in the bare Klein-Gordon theory, intrinsically a result of negative energies, the fact that we here arrive at a theory with positive probabilities, means that negative energy particles are not to be considered problematic as is the case in the bare Klein-Gordon theory. From an abstract-objective stand-point; in comparison with positive energy particles, the corollary is that negative energy particles should have equal chances to exist. As to why these negative energy particles do not exist, this is analogous to asking why is it that Dirac's antimatter does not exist in equal proportions with matter. This problem of why negative energy particles do not exist in equal proportions with positive energy particles is a problem that needs to be solved by a future theory.

Golden Gadzirayi Nyambuya

2013-08-15T23:59:59.000Z

188

Hunting for Snarks in Quantum Mechanics  

SciTech Connect

A long-standing debate over the interpretation of quantum mechanics has centered on the meaning of Schroedinger's wave function {psi} for an electron. Broadly speaking, there are two major opposing schools. On the one side, the Copenhagen school(led by Bohr, Heisenberg and Pauli) holds that {psi} provides a complete description of a single electron state; hence the probability interpretation of {psi}{psi}* expresses an irreducible uncertainty in electron behavior that is intrinsic in nature. On the other side, the realist school(led by Einstein, de Broglie, Bohm and Jaynes) holds that {psi} represents a statistical ensemble of possible electron states; hence it is an incomplete description of a single electron state. I contend that the debaters have overlooked crucial facts about the electron revealed by Dirac theory. In particular, analysis of electron zitterbewegung(first noticed by Schroedinger) opens a window to particle substructure in quantum mechanics that explains the physical significance of the complex phase factor in {psi}. This led to a testable model for particle substructure with surprising support by recent experimental evidence. If the explanation is upheld by further research, it will resolve the debate in favor of the realist school. I give details. The perils of research on the foundations of quantum mechanics have been foreseen by Lewis Carroll in The Hunting of the Snark{exclamation_point}.

Hestenes, David [Physics Department, Arizona State University, Tempe, Arizona 85287 (United States)

2009-12-08T23:59:59.000Z

189

References - symmetrization postulate of quantum mechanics  

Science Conference Proceedings (OSTI)

... Paul Teller, An Interpretative Introduction to Quantum ... Body Systems, 2nd ed. (Academic Press ... Edward Witten, "Duality, Spacetime and Quantum ...

190

Measurement and Ergodicity in Quantum Mechanics  

E-Print Network (OSTI)

The experimental realization of successive non-demolition measurements on single microscopic systems brings up the question of ergodicity in Quantum Mechanics (QM). We inquire whether time averages over one realization of a single system are related to QM averages over an ensemble of similarly prepared systems. We adopt a generalization of von Neumann model of measurement, coupling the system to $N$ "probes" --with a strength that is at our disposal-- and detecting the latter. The model parallels the procedure followed in experiments on Quantum Electrodynamic cavities. The modification of the probability of the observable eigenvalues due to the coupling to the probes can be computed analytically and the results compare qualitatively well with those obtained numerically by the experimental groups. We find that the problem is not ergodic, except in the case of an eigenstate of the observable being studied.

Mariano Bauer; Pier A. Mello

2013-12-25T23:59:59.000Z

191

Quantum-Mechanical Model of Spacetime  

E-Print Network (OSTI)

We consider a possibility to construct a quantum-mechanical model of spacetime, where Planck size quantum black holes act as the fundamental constituents of space and time. Spacetime is assumed to be a graph, where black holes lie on the vertices. Our model implies that area has a discrete spectrum with equal spacing. At macroscopic length scales our model reproduces Einstein's field equation with a vanishing cosmological constant as a sort of thermodynamical equation of state of spacetime and matter fields. In the low temperature limit, where most black holes are assumed to be in the ground state, our model implies the Unruh and the Hawking effects, whereas in the high temperature limit we find, among other things, that black hole entropy depends logarithmically on the event horizon area, instead of being proportional to the area.

Makela, J

2007-01-01T23:59:59.000Z

192

Quantum-Mechanical Model of Spacetime  

E-Print Network (OSTI)

We consider a possibility to construct a quantum-mechanical model of spacetime, where Planck size quantum black holes act as the fundamental constituents of space and time. Spacetime is assumed to be a graph, where black holes lie on the vertices. Our model implies that area has a discrete spectrum with equal spacing. At macroscopic length scales our model reproduces Einstein's field equation with a vanishing cosmological constant as a sort of thermodynamical equation of state of spacetime and matter fields. In the low temperature limit, where most black holes are assumed to be in the ground state, our model implies the Unruh and the Hawking effects, whereas in the high temperature limit we find, among other things, that black hole entropy depends logarithmically on the event horizon area, instead of being proportional to the area.

Jarmo Makela

2007-01-24T23:59:59.000Z

193

5.74 Introductory Quantum Mechanics II, Spring 2005  

E-Print Network (OSTI)

Time-dependent quantum mechanics and spectroscopy. Topics covered include perturbation theory, two-level systems, light-matter interactions, relaxation in quantum systems, correlation functions and linear response theory, ...

Tokmakoff, Andrei

194

Quantum-mechanical linear filtering of random signal sequences  

Science Conference Proceedings (OSTI)

The problem of estimating a member of a scalar random signal sequence with quantum-mechanical measurements is considered. The minimum variance linear estimator based on an optimal present quantum measurement and optimal linear processing of past measurements ...

J. Baras; R. Harger; Young Park

1976-01-01T23:59:59.000Z

195

Modelling Quantum Mechanics by the Quantumlike Description of the Electric Signal Propagation in Transmission Lines  

E-Print Network (OSTI)

It is shown that the transmission line technology can be suitably used for simulating quantum mechanics. Using manageable and at the same time non-expensive technology, several quantum mechanical problems can be simulated for significant tutorial purposes. The electric signal envelope propagation through the line is governed by a Schrodinger-like equation for a complex function, representing the low-frequency component of the signal, In this preliminary analysis, we consider two classical examples, i.e. the Frank-Condon principle and the Ramsauer effect.

R. Fedele; M. A. Man'ko; V. I. Man'ko; V. G. Vaccaro

2002-07-30T23:59:59.000Z

196

Quantum Mechanics Joachim Burgd orfer and Stefan Rotter  

E-Print Network (OSTI)

1 1 Quantum Mechanics Joachim BurgdË? orfer and Stefan Rotter 1.1 Introduction 3 1.2 Particle and Quantization 8 1.5 Angular Momentum in Quantum Mechanics 9 1.6 Formalism of Quantum Mechanics 12 1.7 Solution 29 1.8.3 Resonances 30 1.9 Semiclassical Mechanics 31 1.9.1 The WKB Approximation 31 1.9.2 The EBK

Rotter, Stefan

197

Relativity and quantum mechanics: Jorgensen revisited  

E-Print Network (OSTI)

We first define the functions which ensure the transformation of momentum and energy of a tardyon, the transformation of the wave vector and the frequency of the associated wave. Having done this, we show that they ensure the relativistic invariance of the quotient between momentum and wave vector and between energy and frequency if the product between particle velocity u and phase velocity w is a relativistic invariant (uw=c^2), a condition which is a natural combination of special relativity theory and quantum mechanics.

Bernhard Rothenstein

2007-03-25T23:59:59.000Z

198

On Quantum Capacity and its Bound  

E-Print Network (OSTI)

The quantum capacity of a pure quantum channel and that of classical-quantum-classical channel are discussed in detail based on the fully quantum mechanical mutual entropy. It is proved that the quantum capacity generalizes the so-called Holevo bound.

Masanori Ohya; Igor V. Volovich

2004-06-29T23:59:59.000Z

199

Bhomian Mechanics vs. Standard Quantum Mechanics: a Difference in Experimental Predictions  

E-Print Network (OSTI)

Standard Quantum Mechanics (QM) predicts an anti-intuitive fenomenon here referred to as "quantum autoscattering", which is excluded by Bhomian Mechanics. The scheme of a gedanken experiment testing the QM prediction is briefly discussed.

Artur Szczepanski

2010-02-08T23:59:59.000Z

200

An Intrusion Detection System Using Quantum- mechanical Systems  

Technology Description A quantum mechanical-based device that detects an intrusion across a physical boundary or communication link. Because common

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

What quantum mechanics is trying to tell us  

Science Conference Proceedings (OSTI)

This article presents a novel interpretation of quantum mechanics. It extends the meaning of “measurement” to include all property-indicating facts. Intrinsically

2000-01-01T23:59:59.000Z

202

Derivation of the coefficient squared probability law in quantum mechanics  

E-Print Network (OSTI)

If one assumes there is probability of perception in quantum mechanics, then unitarity dictates that it must have the coefficient squared form, in agreement with experiment.

Casey Blood

2013-06-02T23:59:59.000Z

203

An Intrusion Detection System Using Quantum-Mechanical Systems  

ORNL 2012-G00220/tcc UT-B ID 200701995 10.2012 An Intrusion Detection System Using Quantum-Mechanical Systems Technology Summary Securing property and ...

204

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Other Large Systems Event Sponsor: Leadership Computing Facility Seminar Start Date: Dec 5 2013 - 2:00pm...

205

An efficient method for the calculation of quantum mechanics/molecular mechanics free energies  

Science Conference Proceedings (OSTI)

The combination of quantum mechanics (QM) with molecular mechanics (MM) offers a route to improved accuracy in the study of biological systems

Christopher J. Woods; Frederick R. Manby; Adrian J. Mulholland

2008-01-01T23:59:59.000Z

206

Quantum mechanics as quantum information (and only a little more), Quantum Theory: Reconsideration of Foundations  

E-Print Network (OSTI)

In this paper, I try once again to cause some good-natured trouble. The issue remains, when will we ever stop burdening the taxpayer with conferences devoted to the quantum foundations? The suspicion is expressed that no end will be in sight until a means is found to reduce quantum theory to two or three statements of crisp physical (rather than abstract, axiomatic) significance. In this regard, no tool appears better calibrated for a direct assault than quantum information theory. Far from a strained application of the latest fad to a time-honored problem, this method holds promise precisely because a large part—but not all—of the structure of quantum theory has always concerned information. It is just that the physics community needs reminding. This paper, though takingquant-ph/0106166 as its core, corrects one mistake and offers several observations beyond the previous version. In particular, I identify one element of quantum mechanics that I would not label a subjective term in the theory—it is the integer parameter D traditionally ascribed to a quantum system via its Hilbert-space dimension. 1

Christopher A. Fuchs

2002-01-01T23:59:59.000Z

207

On inverse problems in electromagnetic field in classical mechanics at fixed energy  

E-Print Network (OSTI)

In this paper, we consider inverse scattering and inverse boundary value problems at sufficiently large and fixed energy for the multidimensional relativistic and nonrelativistic Newton equations in a static external electromagnetic field $(V,B)$, $V\\in C^2,$ $B\\in C^1$ in classical mechanics. Developing the approach going back to Gerver-Nadirashvili 1983's work on an inverse problem of mechanics, we obtain, in particular, theorems of uniqueness.

Alexandre Jollivet

2007-01-04T23:59:59.000Z

208

Quantum mechanical evolution towards thermal equilibrium  

E-Print Network (OSTI)

The circumstances under which a system reaches thermal equilibrium, and how to derive this from basic dynamical laws, has been a major question from the very beginning of thermodynamics and statistical mechanics. Despite considerable progress, it remains an open problem. Motivated by this issue, we address the more general question of equilibration. We prove, with virtually full generality, that reaching equilibrium is a universal property of quantum systems: Almost any subsystem in interaction with a large enough bath will reach an equilibrium state and remain close to it for almost all times. We also prove several general results about other aspects of thermalisation besides equilibration, for example, that the equilibrium state does not depend on the detailed micro-state of the bath.

Noah Linden; Sandu Popescu; Anthony J. Short; Andreas Winter

2008-12-12T23:59:59.000Z

209

New methods for quantum mechanical reaction dynamics  

DOE Green Energy (OSTI)

Quantum mechanical methods are developed to describe the dynamics of bimolecular chemical reactions. We focus on developing approaches for directly calculating the desired quantity of interest. Methods for the calculation of single matrix elements of the scattering matrix (S-matrix) and initial state-selected reaction probabilities are presented. This is accomplished by the use of absorbing boundary conditions (ABC) to obtain a localized (L{sup 2}) representation of the outgoing wave scattering Green`s function. This approach enables the efficient calculation of only a single column of the S-matrix with a proportionate savings in effort over the calculation of the entire S-matrix. Applying this method to the calculation of the initial (or final) state-selected reaction probability, a more averaged quantity, requires even less effort than the state-to-state S-matrix elements. It is shown how the same representation of the Green`s function can be effectively applied to the calculation of negative ion photodetachment intensities. Photodetachment spectroscopy of the anion ABC{sup -} can be a very useful method for obtaining detailed information about the neutral ABC potential energy surface, particularly if the ABC{sup -} geometry is similar to the transition state of the neutral ABC. Total and arrangement-selected photodetachment spectra are calculated for the H{sub 3}O{sup -} system, providing information about the potential energy surface for the OH + H{sub 2} reaction when compared with experimental results. Finally, we present methods for the direct calculation of the thermal rate constant from the flux-position and flux-flux correlation functions. The spirit of transition state theory is invoked by concentrating on the short time dynamics in the area around the transition state that determine reactivity. These methods are made efficient by evaluating the required quantum mechanical trace in the basis of eigenstates of the Boltzmannized flux operator.

Thompson, W.H. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States)

1996-12-01T23:59:59.000Z

210

A Causal Net Approach to Relativistic Quantum Mechanics  

E-Print Network (OSTI)

In this paper we discuss a causal network approach to describing relativistic quantum mechanics. Each vertex on the causal net represents a possible point event or particle observation. By constructing the simplest causal net based on Reichenbach-like conjunctive forks in proper time we can exactly derive the 1+1 dimension Dirac equation for a relativistic fermion and correctly model quantum mechanical statistics. Symmetries of the net provide various quantum mechanical effects such as quantum uncertainty and wavefunction, phase, spin, negative energy states and the effect of a potential. The causal net can be embedded in 3+1 dimensions and is consistent with the conventional Dirac equation. In the low velocity limit the causal net approximates to the Schrodinger equation and Pauli equation for an electromagnetic field. Extending to different momentum states the net is compatible with the Feynman path integral approach to quantum mechanics that allows calculation of well known quantum phenomena such as diffraction.

R. D. Bateson

2010-07-14T23:59:59.000Z

211

Environment-Induced Decoherence in Noncommutative Quantum Mechanics  

E-Print Network (OSTI)

We address the question of the appearence of ordinary quantum mechanics in the context of noncommutative quantum mechanics. We obtain the noncommutative extension of the Hu-Paz-Zhang master equation for a Brownian particle linearly coupled to a bath of harmonic oscillators. We consider the particular case of an Ohmic regime.

Joao Nuno Prata; Nuno Costa Dias

2006-12-02T23:59:59.000Z

212

Testing axioms for Quantum Mechanics on Probabilistic toy-theories  

E-Print Network (OSTI)

In Ref. [1] one of the authors proposed postulates for axiomatizing Quantum Mechanics as a "fair operational framework", namely regarding the theory as a set of rules that allow the experimenter to predict future events on the basis of suitable tests, having local control and low experimental complexity. In addition to causality, the following postulates have been considered: PFAITH (existence of a pure preparationally faithful state), and FAITHE (existence of a faithful effect). These postulates have exhibited an unexpected theoretical power, excluding all known nonquantum probabilistic theories. Later in Ref. [2] in addition to causality and PFAITH, postulate LDISCR (local discriminability) and PURIFY (purifiability of all states) have been considered, narrowing the probabilistic theory to something very close to Quantum Mechanics. In the present paper we test the above postulates on some nonquantum probabilistic models. The first model, "the two-box world" is an extension of the Popescu-Rohrlich model, which achieves the greatest violation of the CHSH inequality compatible with the no-signaling principle. The second model "the two-clock world" is actually a full class of models, all having a disk as convex set of states for the local system. One of them corresponds to the "the two-rebit world", namely qubits with real Hilbert space. The third model--"the spin-factor"--is a sort of n-dimensional generalization of the clock. Finally the last model is "the classical probabilistic theory". We see how each model violates some of the proposed postulates, when and how teleportation can be achieved, and we analyze other interesting connections between these postulate violations, along with deep relations between the local and the non-local structures of the probabilistic theory.

Giacomo Mauro D'Ariano; Alessandro Tosini

2009-11-29T23:59:59.000Z

213

Asymptotically Free Yang-Mills Classical Mechanics with Self-Linked Orbits  

E-Print Network (OSTI)

We construct a classical mechanics Hamiltonian which exhibits spontaneous symmetry breaking akin the Coleman-Weinberg mechanism, dimensional transmutation, and asymptotically free self-similarity congruent with the beta-function of four dimensional Yang-Mills theory. Its classical equations of motion support stable periodic orbits and in a three dimensional projection these orbits are self-linked into topologically nontrivial, toroidal knots. The non-perturbative structure of four dimensional Yang-Mills theory continues to be the subject of extensive investigations. A major goal is the understanding of large distance properties such as color confinement, mass gap and the glueball spectrum. The Yang-Mills theory has also a number of well established salient features like ultraviolet asymptotic freedom and the presence of finite action instantons. Here we shall introduce a classical mechanics Hamiltonian which contains many incredients of the four dimensional Yang-Mills field theory, even though it is defined in a four dimensional phase space. These include asymptotically free self-similarity with a coupling constant that flows like the one loop coupling constant of four dimensional Yang-Mills theory, dimensional transmutation, and spontaneous symmetry breaking akin the Coleman-Weinberg mechanism. Furthermore, we find that its Hamilton’s equations support stable periodic

M. Lübcke; A. J. Niemi; K. Torokoff

2008-01-01T23:59:59.000Z

214

Quantum Dating Market  

E-Print Network (OSTI)

We consider the dating market decision problem under the quantum mechanics point of view. Quantum states whose associated amplitudes are modified by men strategies are used to represent women. Grover quantum search algorithm is used as a playing strategy. Success is more frequently obtained by playing quantum than playing classic.

O. G. Zabaleta; C. M. Arizmendi

2010-03-04T23:59:59.000Z

215

Quantum Walks Norio Konno  

E-Print Network (OSTI)

Quantum Walks Norio Konno Yokohama National University Two types of quantum (random) walks, discrete-time (coined) or continuous- time, were introduced as the quantum mechanical extension of the corresponding classical random walks in connection with quantum computing and have been extensively studied over

Schürmann, Michael

216

Experimental verification of a one-parameter scaling law for the quantum and "classical" resonances of the atom-optics kicked rotor  

E-Print Network (OSTI)

We present experimental measurements of the mean energy in the vicinity of the first and second quantum resonances of the atom optics kicked rotor for a number of different experimental parameters. Our data is rescaled and compared with the one parameter epsilon--classical scaling function developed to describe the quantum resonance peaks. Additionally, experimental data is presented for the ``classical'' resonance which occurs in the limit as the kicking period goes to zero. This resonance is found to be analogous to the quantum resonances, and a similar one-parameter classical scaling function is derived, and found to match our experimental results. The width of the quantum and classical resonance peaks is compared, and their Sub-Fourier nature examined.

Sandro Wimberger; Mark Sadgrove; Scott Parkins; Rainer Leonhardt

2005-02-11T23:59:59.000Z

217

Efficiency of the general quantum-mechanical Carnot engine  

E-Print Network (OSTI)

A quantum-mechanical analog of the Carnot engine reversibly working at vanishing temperature, shortly termed the quantum-mechanical Carnot engine, is discussed. A general formula for the efficiency of such an engine with an arbitrary confining potential is presented. Its expression is purely given in terms of the structure of the energy spectrum. Dependency of the efficiency on the form of a potential as an analog of the working material in thermodynamics implies nonuniversality of the engine. This may be due to the absence of the second-law-like principle in pure-state quantum mechanics.

Sumiyoshi Abe

2012-08-10T23:59:59.000Z

218

24.111 Philosophy of Quantum Mechanics, Spring 2002  

E-Print Network (OSTI)

Quantum mechanics is said to describe a world in which physical objects often lack "definite" properties, indeterminism creeps in at the point of "observation," ordinary logic does not apply, and distant events are perfectly ...

Hall, Edward J. (Edward Jonathon), 1966-

219

On feedback and the classical capacity of a noisy quantum channel  

Science Conference Proceedings (OSTI)

In Shannon information theory, the capacity of a memoryless communication channel cannot be increased by the use of feedback from receiver to sender. In this correspondence, the use of classical feedback is shown to provide no increase in the unassisted ...

G. Bowen; R. Nagarajan

2005-01-01T23:59:59.000Z

220

Nonlinear coupling of nano mechanical resonators to Josephson quantum circuits  

E-Print Network (OSTI)

We propose a technique to couple the position operator of a nano mechanical resonator to a SQUID device by modulating its magnetic flux bias. By tuning the magnetic field properly, either linear or quadratic couplings can be realized, with a discretely adjustable coupling strength. This provides a way to realize coherent nonlinear effects in a nano mechanical resonator by coupling it to a Josephson quantum circuit. As an example, we show how squeezing of the nano mechanical resonator state can be realized with this technique. We also propose a simple method to measure the uncertainty in the position of the nano mechanical resonator without quantum state tomography.

Xingxiang Zhou; Ari Mizel

2006-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Biased nonlocal quantum games  

E-Print Network (OSTI)

We address the question of when quantum entanglement is a useful resource for information processing tasks by presenting a new class of nonlocal games that are simple, direct, generalizations of the Clauser Horne Shimony Holt game. For some ranges of the parameters that specify the games, quantum mechanics offers an advantage, while, surprisingly, for others quantum mechanics is no more powerful than classical mechanics in performing the nonlocal task. This sheds new light on the difference between classical, quantum and super-quantum correlations.

Thomas Lawson; Noah Linden; Sandu Popescu

2010-11-29T23:59:59.000Z

222

Quantization in relativistic classical mechanics: the Stueckelberg equation, neutrino oscillation and large-scale structure of the Universe  

E-Print Network (OSTI)

Based on the Chetaev theorem on stable dynamical trajectories in the presence of dissipative forces, we obtain the generalized condition for stability of relativistic classical Hamiltonian systems (with an invariant evolution parameter) in the form of the Stueckelberg equation. As is known, this equation is the basis of a competing paradigm known as parametrized relativistic quantum mechanics (pRQM). It is shown that the energy of dissipative forces, which generate the Chetaev generalized condition of stability, coincides exactly with Bohmian relativistic quantum potential. We show that the squared amplitude of a wave function in the Stueckelberg equation is equivalent to the probability density function for the number of particle trajectories, relative to which the velocity and the position of the particle are not hidden parameters. The conditions for reasonableness of trajectory interpretation of pRQM are discussed. On basis of analysis of a general formalism for vacuum-flavor mixing of neutrino within the context of the standard and pRQM models we show that the corresponding expressions for the probability of transition from one neutrino flavor to another differ appreciably, but they are experimentally testable: the estimations of absolute value for neutrino mass based on modern experimental data for solar and atmospheric neutrinos show that the pRQM results have a preference. It is noted that the selection criterion of mass solutions relies on proximity between the average size of condensed neutrino clouds, which is described by the Muraki formula (29th ICRC, 2005) and depends on the neutrino mass, and the average size of typical observed void structure (dark matter + hydrogen gas), which plays the role of characteristic dimension of large-scale structure of the Universe.

V. D. Rusov; D. S. Vlasenko

2012-02-07T23:59:59.000Z

223

Binary mixture of pseudo-spin-(1/2) Bose gases with interspecies spin exchange: From classical fixed points and ground states to quantum ground states  

SciTech Connect

We consider the effective spin Hamiltonian describing a mixture of two species of pseudo-spin-(1/2) Bose gases with interspecies spin exchange. First we analyze the stability of the fixed points of the corresponding classical dynamics, of which the signature is found in quantum dynamics with a disentangled initial state. Focusing on the case without an external potential, we find all the ground states by taking into account quantum fluctuations around the classical ground state in each parameter regime. The nature of entanglement and its relation with classical bifurcation is investigated. When the total spins of the two species are unequal, the maximal entanglement at the parameter point of classical bifurcation is possessed by the excited state corresponding to the classical fixed point which bifurcates, rather than by the ground state.

Wu Rukuan [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Shi Yu [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China)

2011-12-15T23:59:59.000Z

224

The clouds of physics and Einstein's last query: Can quantum mechanics be derived from general relativity?  

E-Print Network (OSTI)

Towards the end of the 19th century, Kelvin pronounced as the "clouds of physics" 1) the failure of the Michelson-Morely experiment to detect an ether wind, 2) the violation of the classical mechanical equipartition theorem in statistical thermodynamics. And he believed that the removal of these clouds would bring physics to an end. But as we know, the removal of these clouds led to the two great breakthoughts of modern physics: 1) The theory of relativity, and 2) to quantum mechanics. Towards the end of the 20th century more clouds of physics became apparent. They are 1) the riddle of quantum gravity, 2) the superluminal quantum correlations, 3) the small cosmological constant. Furthermore, there is the riddle of dark energy making up 70% of the physical universe, the non-baryonic cold dark matter making up 26% and the very small initial entropy of the universe. An attempt is made to explain the importance of these clouds for the future of physics. Conjectures for a possible solution are presented. they have to do with Einstein's last query: "Can quantum mechanics be derived general relativity", and with the question is there an ether?

Friedwardt Winterberg

2008-05-20T23:59:59.000Z

225

UNIFORM SEMICLASSICAL APPROXIMATION IN QUANTUM STATISTICAL MECHANICS.  

SciTech Connect

We present a simple method to deal with caustics in the semiclassical approximation to the partition function of a one-dimensional quantum system. The procedure, which makes use of complex trajectories, is applied to the quartic double-well potential.

De Carvalho, C.A.A.; Cavalcanit, R.M.; Fraga, E.S.; Joras, S.E.

2000-10-23T23:59:59.000Z

226

Assessing Expertise in Quantum Mechanics using Categorization Task  

Science Conference Proceedings (OSTI)

We discuss the categorization of 20 quantum mechanics problems by 6 physics professors and 22 undergraduate students from two honors?level quantum mechanics courses. Professors and students were asked to categorize the problems based upon similarity of solution. We also had individual discussions with professors who categorized the problems. Faculty members’ categorizations were overall rated better than those of students by three faculty members who evaluated all of the categorizations. But the categories created by faculty members were more diverse compared to the uniformity of the categories they created when asked to categorize introductory mechanics problems.

Shih?Yin Lin; Chandralekha Singh

2009-01-01T23:59:59.000Z

227

Quantum-mechanical description of spin-1 particles with electric dipole moments  

E-Print Network (OSTI)

The Proca-Corben-Schwinger equations for a spin-1 particle with an anomalous magnetic moment are added by a term describing an electric dipole moment, then they are reduced to a Hamiltonian form, and finally they are brought to the Foldy-Wouthuysen representation. Relativistic equations of motion are derived. The needed agreement between quantum-mechanical and classical relativistic equations of motion is proved. The scalar and tensor electric and magnetic polarizabilities of pointlike spin-1 particles (W bosons) are calculated for the first time.

Alexander J. Silenko

2013-03-26T23:59:59.000Z

228

Quantum mechanics in curved space-time II  

E-Print Network (OSTI)

This paper is a sequence of the work presented in [1], where, the principles of the general relativity have been used to formulate quantum wave equations taking into account the effect of the electromagnetic and strong interactions in the space-time metric of quantum systems. Now, the role of the energy-momentum tensor in this theory is studied, and it is consistent with the formulation of the general quantum mechanics shown in [1]. With this procedure, a dynamical cut-off is generated and the constant $A$ of the field equation is calculated.

C. C. Barros Jr

2005-09-01T23:59:59.000Z

229

On the Limits of Information Retrieval in Quantum Mechanics  

E-Print Network (OSTI)

The widely considered assertion is that the unitarity of quantum mechanical evolution assures the preservation of information. It is even promoted in popular literature as an established fact. (Susskind, 2008) Yet, a simple chain of reasoning demonstrates that: 1) almost any evolutionary operator can be well approximated by a degenerate (finite-rank) operator and 2) one needs an eternity to retrieve information exactly from a nonstationary quantum state and to distinguish between arbitrary unitary operator and its finite-dimensional approximations.

Peter B. Lerner

2013-11-26T23:59:59.000Z

230

Quantum mechanics from an equivalence principle  

Science Conference Proceedings (OSTI)

The authors show that requiring diffeomorphic equivalence for one-dimensional stationary states implies that the reduced action S{sub 0} satisfies the quantum Hamilton-Jacobi equation with the Planck constant playing the role of a covariantizing parameter. The construction shows the existence of a fundamental initial condition which is strictly related to the Moebius symmetry of the Legendre transform and to its involutive character. The universal nature of the initial condition implies the Schroedinger equation in any dimension.

Faraggi, A.E. [Univ. of Florida, Gainesville, FL (United States). Inst. for Fundamental Theory; Matone, M. [Univ. of Padova (Italy)

1997-05-15T23:59:59.000Z

231

The classical capacity achievable by a quantum channel assisted by limited entanglement  

E-Print Network (OSTI)

We give the trade-off curve showing the capacity of a quantum channel as a function of the amount of entanglement used by the sender and receiver for transmitting information. The endpoints of this curve are given by the Holevo-Schumacher-Westmoreland capacity formula and the entanglement-assisted capacity, which is the maximum over all input density matrices of the quantum mutual information. The proof we give is based on the Holevo-Schumacher-Westmoreland formula, and also gives a new and simpler proof for the entanglement-assisted capacity formula.

Peter W. Shor

2004-02-18T23:59:59.000Z

232

Quantum Field Theory Is Not Merely Quantum Mechanics Applied to Low Energy Effective Degrees of Freedom  

E-Print Network (OSTI)

It is commonly assumed that quantum field theory arises by applying ordinary quantum mechanics to the low energy effective degrees of freedom of a more fundamental theory defined at ultra-high-energy/short-wavelength scales. We shall argue here that, even for free quantum fields, there are holistic aspects of quantum field theory that cannot be properly understood in this manner. Specifically, the ``subtractions'' needed to define nonlinear polynomial functions of a free quantum field in curved spacetime are quite simple and natural from the quantum field theoretic point of view, but are at best extremely ad hoc and unnatural if viewed as independent renormalizations of individual modes of the field. We illustrate this point by contrasting the analysis of the Casimir effect, the renormalization of the stress-energy tensor in time-dependent spacetimes, and anomalies from the point of quantum field theory and from the point of view of quantum mechanics applied to the independent low energy modes of the field. Some implications for the cosmological constant problem are discussed.

Stefan Hollands; Robert M. Wald

2004-05-16T23:59:59.000Z

233

An ultra-low dissipation micro-oscillator for quantum opto-mechanics  

E-Print Network (OSTI)

Generating non-classical states of light by opto-mechanical coupling depends critically on the mechanical and optical properties of micro-oscillators and on the minimization of thermal noise. We present an oscillating micro-mirror with a mechanical quality factor Q = 2.6x10^6 at cryogenic temperature and a Finesse of 65000, obtained thanks to an innovative approach to the design and the control of mechanical dissipation. Already at 4 K with an input laser power of 2 mW, the radiation-pressure quantum fluctuations become the main noise source, overcoming thermal noise. This feature makes our devices particularly suitable for the production of pondero-motive squeezing.

E. Serra; A. Borrielli; F. S. Cataliotti; F. Marin; F. Marino; A. Pontin; G. A. Prodi; M. Bonaldi

2012-08-30T23:59:59.000Z

234

An ultra-low dissipation micro-oscillator for quantum opto-mechanics  

E-Print Network (OSTI)

Generating non-classical states of light by opto-mechanical coupling depends critically on the mechanical and optical properties of micro-oscillators and on the minimization of thermal noise. We present an oscillating micro-mirror with a mechanical quality factor Q = 2.6x10^6 at cryogenic temperature and a Finesse of 65000, obtained thanks to an innovative approach to the design and the control of mechanical dissipation. Already at 4 K with an input laser power of 2 mW, the radiation-pressure quantum fluctuations become the main noise source, overcoming thermal noise. This feature makes our devices particularly suitable for the production of pondero-motive squeezing.

Serra, E; Cataliotti, F S; Marin, F; Marino, F; Pontin, A; Prodi, G A; Bonaldi, M

2012-01-01T23:59:59.000Z

235

Communication cost of classically simulating a quantum channel with subsequent rank-1 projective measurement  

E-Print Network (OSTI)

A process of preparation, transmission and subsequent projective measurement of a qubit can be simulated by a classical model with only two bits of communication and some amount of shared randomness. However no model for n qubits with a finite amount of classical communication is known at present. A lower bound for the communication cost can provide useful hints for a generalization. It is known for example that the amount of communication must be greater than c 2^n, where c~0.01. The proof uses a quite elaborate theorem of communication complexity. Using a mathematical conjecture known as the "double cap conjecture", we strengthen this result by presenting a geometrical and extremely simple derivation of the lower bound 2^n-1. Only rank-1 projective measurements are involved in the derivation.

Alberto Montina

2011-10-26T23:59:59.000Z

236

Communication cost of classically simulating a quantum channel with subsequent rank-1 projective measurement  

E-Print Network (OSTI)

A process of preparation, transmission and subsequent projective measurement of a qubit can be simulated by a classical model with only two bits of communication and some amount of shared randomness. However no model for n qubits with a finite amount of classical communication is known at present. A lower bound for the communication cost can provide useful hints for a generalization. It is known for example that the amount of communication must be greater than c 2^n, where c~0.01. The proof uses a quite elaborate theorem of communication complexity. Using a mathematical conjecture known as the "double cap conjecture", we strengthen this result by presenting a geometrical and extremely simple derivation of the lower bound 2^n-1. Only rank-1 projective measurements are involved in the derivation.

Montina, Alberto

2011-01-01T23:59:59.000Z

237

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and  

NLE Websites -- All DOE Office Websites (Extended Search)

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Other Large Systems Event Sponsor: Leadership Computing Facility Seminar Start Date: Dec 5 2013 - 2:00pm Building/Room: Building 240/Room 4301 Location: Argonne National Laboratory Speaker(s): Dmitri G. Fedorov Speaker(s) Title: National Institute of Advanced Industrial Science and Technology (AIST) Host: Yuri Alexeev Our approach to large scale calculations is based on fragmenting a molecular system into pieces, and performing quantum-mechanical calculations of these fragments and their pairs in the fragment molecular orbital method (FMO). After a brief summary of the methodology, some typical applications to protein-ligand complexes, chemical reactions in explicit solvent, and nanomaterials (silicon nanowires, zeolites.

238

Hydrodynamical interpretation of quantum mechanics: the momentum distribution  

E-Print Network (OSTI)

The quantum mechanics is considered to be a partial case of the stochastic system dynamics. It is shown that the wave function describes the state of statistically averaged system $$, but not that of the individual stochastic system $\\mathcal{S}_{st}$. It is a common practice to think that such a construction of quantum mechanics contains hidden variables, and it is incompatible with the von Neumann's theorem on hidden variables. It is shown that the original conditions of the von Neumann's theorem are not satisfied. In particular, the quantum mechanics cannot describe the particle momentum distribution. The distribution $w(\\mathbf{p}) =| \\psi_{p%}| ^{2}$ is not a particle momentum distribution at the state $\\psi $, because it cannot be attributed to a wave function. It is closer to the mean momentum distribution, although the two distributions do not coincide exactly.

Yuri A. Rylov

2004-02-15T23:59:59.000Z

239

Dynamical probability, particle trajectories and completion of traditional quantum mechanics  

E-Print Network (OSTI)

Maintaining the position that the wave function $\\psi$ provides a complete description of state, the traditional formalism of quantum mechanics is augmented by introducing continuous trajectories for particles which are sample paths of a stochastic process determined (including the underlying probability space) by $\\psi$. In the resulting formalism, problems relating to measurements and objective reality are solved as in Bohmian mechanics (without sharing its weak points). The pitfalls of Nelson's stochastic mechanics are also avoided.

Tulsi Dass

2005-05-25T23:59:59.000Z

240

PERTURBATION-THEORY RULES FOR COMPUTING THE SELF-ENERGY OPERATOR IN QUANTUM STATISTICAL MECHANICS  

E-Print Network (OSTI)

J. Thouless) The Quantu~ Mechanics of V ~ny-Body Systems (IN QUANTUM STA TISTICAL MECHANICS Gordon BayrrL and AndrewIN QUANTUM STATISTICAL MECHANICS Gordon Baym and Andrew M.

Baym, Gordon

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Open Quantum to classical phases transition in the stochastic hydrodynamic analogy: the explanation of the Lindemann relation and the analogies between the maximum of density at He lambda point and that one at water-ice phase transition  

E-Print Network (OSTI)

In the present paper the gas, liquid and solid phases made of structureless particles, are visited to the light of the quantum stochastic hydrodynamic analogy (SQHA). The SQHA shows that the open quantum mechanical behavior is maintained on a distance shorter than the theory-defined quantum correlation length (lc). When, the physical length of the problem is larger than lc, the model shows that the quantum (potential) interactions may have a finite range of interaction maintaining the non-local behavior on a finite distance quantum non-locality length lq. The present work shows that when the mean molecular distance is larger than the quantum non-locality length we have a classical phases (gas and van der Waals liquids) while when the mean molecular distance becomes smaller than lq or than lc we have phases such as the solid crystal or the superfluid one, respectively, that show quantum characteristics. The model agrees with Lindemann empirical law (and explains it), for the mean square deviation of atom from the equilibrium position at melting point of crystal, and shows a connection between the maximum density at the He lambda point and that one near the water-ice solidification point.

Piero Chiarelli

2013-05-07T23:59:59.000Z

242

On the alternatives for bath correlators and spectral densities from mixed quantum-classical simulations  

Science Conference Proceedings (OSTI)

We investigate on the procedure of extracting a 'spectral density' from mixed QM/MM calculations and employing it in open quantum systems models. In particular, we study the connection between the energy gap correlation function extracted from ground state QM/MM and the bath spectral density used as input in open quantum system approaches. We introduce a simple model which can give intuition on when the ground state QM/MM propagation will give the correct energy gap. We also discuss the role of higher order correlators of the energy-gap fluctuations which can provide useful information on the bath. Further, various semiclassical corrections to the spectral density, are applied and investigated. Finally, we apply our considerations to the photosynthetic Fenna-Matthews-Olson complex. For this system, our results suggest the use of the Harmonic prefactor for the spectral density rather than the Standard one, which was employed in the simulations of the system carried out to date.

Valleau, Stephanie; Aspuru-Guzik, Alan [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Eisfeld, Alexander [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)

2012-12-14T23:59:59.000Z

243

Comment on ''Secret-key-assisted private classical communication capacity over quantum channels''  

Science Conference Proceedings (OSTI)

The paper of Hsieh, Luo, and Brun (HLB) [Phys. Rev. A 78, 042306 (2008)] contains several issues with the capacity theorem presented there, one of which is the suggestion that a sender and receiver can achieve entanglement-assisted classical capacity without any entanglement at all, and another of which is a violation of the Holevo bound. There is also an issue with the converse proof of the capacity theorem. In this comment, I point out these issues and provide revisions of the capacity theorem and the converse proof.

Wilde, Mark M. [School of Computer Science, McGill University, Montreal, Quebec H3A 2A7 (Canada)

2011-04-15T23:59:59.000Z

244

Decoherent Histories Quantum Mechanics with One 'Real' Fine-Grained History  

E-Print Network (OSTI)

Decoherent histories quantum theory is reformulated with the assumption that there is one "real" fine-grained history, specified in a preferred complete set of sum-over-histories variables. This real history is described by embedding it in an ensemble of comparable imagined fine-grained histories, not unlike the familiar ensemble of statistical mechanics. These histories are assigned extended probabilities, which can sometimes be negative or greater than one. As we will show, this construction implies that the real history is not completely accessible to experimental or other observational discovery. However, sufficiently and appropriately coarse-grained sets of alternative histories have standard probabilities providing information about the real fine-grained history that can be compared with observation. We recover the probabilities of decoherent histories quantum mechanics for sets of histories that are recorded and therefore decohere. Quantum mechanics can be viewed as a classical stochastic theory of histories with extended probabilities and a well-defined notion of reality common to all decoherent sets of alternative coarse-grained histories.

Murray Gell-Mann; James B. Hartle

2011-06-03T23:59:59.000Z

245

Quantum Computing and Lie Theory Feynman's suggestion that the only effective way to model quantum phe-  

E-Print Network (OSTI)

Quantum Computing and Lie Theory Feynman's suggestion that the only effective way to model quantum phe- nomena on a computer would be to build a computer that made use of quantum mechanics was one of the cornerstones of the birth of quantum com- puting. In his later years he studied both classical and quantum

D'Agnolo, Andrea

246

Persistent dynamic entanglement from classical motion: How bio-molecular machines can generate non-trivial quantum states  

E-Print Network (OSTI)

Very recently [Phys. Rev. E 82, 021921 (2010)] a simple mechanism was presented by which a molecule subjected to forced oscillations, out of thermal equilibrium, can maintain quantum entanglement between two of its quantum degrees of freedom. Crucially, entanglement can be maintained even in the presence of very intense noise, so intense that no entanglement is possible when the forced oscillations cease. This mechanism may allow for the presence of non-trivial quantum entanglement in biological systems. Here we significantly enlarge the study of this model. In particular, we show that the persistent generation of dynamic entanglement is not restricted to the bosonic heat bath model, but it can also be observed in other decoherence models, e.g. the spin gas model, and in non-Markovian scenarios. We also show how conformational changes can be used by an elementary machine to generate entanglement even in unfavorable conditions. In biological systems, similar mechanisms could be exploited by more complex molecular machines or motors.

Gian Giacomo Guerreschi; Jianming Cai; Sandu Popescu; Hans J. Briegel

2011-11-09T23:59:59.000Z

247

Jordan-Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization  

E-Print Network (OSTI)

In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown {\\it a priori}. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman SU(3) symmetry group matrices. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that generalized Stokes Operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization density matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical three-dimensional isotropic harmonic oscillator we describe the geometric properties of the polarization ellipse

R. D. Mota; M. A. Xicotencatl; V. D. Granados

2008-01-30T23:59:59.000Z

248

Quantum-mechanical theory of optomechanical Brillouin cooling  

SciTech Connect

We analyze how to exploit Brillouin scattering of light from sound for the purpose of cooling optomechanical devices and present a quantum-mechanical theory for Brillouin cooling. Our analysis shows that significant cooling ratios can be obtained with standard experimental parameters. A further improvement of cooling efficiency is possible by increasing the dissipation of the optical anti-Stokes resonance.

Tomes, Matthew; Bahl, Gaurav; Carmon, Tal [Department of Electrical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Marquardt, Florian [Institut fuer Theoretische Physik, Universitaet Erlangen-Nuernberg, Staudtstrasse 7, D-91058 Erlangen (Germany); Max Planck Institute for the Science of Light, Guenther-Scharowsky-Strasse 1/Bau 24, D-91058 Erlangen (Germany)

2011-12-15T23:59:59.000Z

249

Monte-carlo calculations for some problems of quantum mechanics  

Science Conference Proceedings (OSTI)

The Monte-Carlo technique for the calculations of functional integral in two one-dimensional quantum-mechanical problems had been applied. The energies of the bound states in some potential wells were obtained using this method. Also some peculiarities in the calculation of the kinetic energy in the ground state had been studied.

Novoselov, A. A., E-mail: novoselov@goa.bog.msu.ru; Pavlovsky, O. V.; Ulybyshev, M. V. [Moscow State University (Russian Federation)

2012-09-15T23:59:59.000Z

250

Quantum mechanical cluster calculations of critical scintillationprocesses  

SciTech Connect

This paper describes the use of commercial quantum chemistrycodes to simu-late several critical scintillation processes. The crystalis modeled as a cluster of typically 50 atoms embedded in an array oftypically 5,000 point charges designed to reproduce the electrostaticfield of the infinite crystal. The Schrodinger equation is solved for theground, ionized, and excited states of the system to determine the energyand electron wavefunction. Computational methods for the followingcritical processes are described: (1) the formation and diffusion ofrelaxed holes, (2) the formation of excitons, (3) the trapping ofelectrons and holes by activator atoms, (4) the excitation of activatoratoms, and (5) thermal quenching. Examples include hole diffusion in CsI,the exciton in CsI, the excited state of CsI:Tl, the energy barrier forthe diffusion of relaxed holes in CaF2 and PbF2, and prompt hole trappingby activator atoms in CaF2:Eu and CdS:Te leading to an ultra-fast (<50ps) scintillation risetime.

Derenzo, Stephen E.; Klintenberg, Mattias K.; Weber, Marvin J.

2000-02-22T23:59:59.000Z

251

Pre-geometric structure of quantum and classical particles in terms of quaternion spinors  

E-Print Network (OSTI)

It is shown that dyad vectors on a local domain of complex-number valued surface, when squared, form a set of four quaternion algebra units. A model of proto-particle is built by the dyad's rotation and stretching; this transformation violates metric properties of the surface, but the defect is cured by a stability condition for normalization functional over an abstract space. If the space is the physical one then the stability condition is precisely Schrodinger equation; separated real and imaginary parts of the condition are respectively equation of mass conservation and Hamilton-Jacoby equation. A 3D particle (composed of the proto-particle's parts) has to be conceived as a rotating massive point, its Lagrangian automatically becoming that of relativistic classical particle, energy and momentum proportional to Planck constant. In uence of a vector ?eld onto the particle's propagation causes automatic appearance of Pauli spin term in Schrodinger equation.

Alexander P. Yefremov

2012-12-25T23:59:59.000Z

252

An investigation of precision and scaling issues in nuclear spin and trapped-ion quantum simulators  

E-Print Network (OSTI)

Quantum simulation offers the possibility of using a controllable quantum-mechanical system to implement the dynamics of another quantum system, performing calculations that are intractable on classical computers for all ...

Clark, Robert J., Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

253

Quantum and classical vibrational relaxation dynamics of N-methylacetamide on ab initio potential energy surfaces  

E-Print Network (OSTI)

Employing extensive quantum-chemical calculations at the DFT/B3LYP and MP2 level, a quartic force field of isolated N-methylacetamide is constructed. Taking into account 24 vibrational degrees of freedom, the model is employed to perform numerically exact vibrational configuration interaction calculations of the vibrational energy relaxation of the amide I mode. It is found that the energy transfer pathways may sensitively depend on details of the theoretical description. Moreover, the exact reference calculations were used to study the applicability and accuracy of (i) the quasiclassical trajectory method, (ii) time-dependent second-order perturbation theory, and (iii) the instantaneous normal mode description of frequency fluctuations. Based on the results, several strategies to describe vibrational energy relaxation in biomolecular systems are discussed.

Fujisaki, Hiroshi; Hirao, Kimihiko; Straub, John E; Stock, Gerhard

2008-01-01T23:59:59.000Z

254

The Free-Will Postulate in Quantum Mechanics  

E-Print Network (OSTI)

The so-called "free will axiom" is an essential ingredient in many discussions concerning hidden variables in quantum mechanics. In this paper we argue that "free will" can be defined in different ways. The definition usually employed is clearly invalid in strictly deterministic theories. A different, more precise formulation is proposed here, defining a condition that may well be a more suitable one to impose on theoretical constructions and models. Our axiom, to be referred to as the `unconstrained initial state' condition, has consequences similar to "free will", but does not clash with determinism, and appears to lead to different conclusions concerning causality and locality in quantum mechanics. Models proposed earlier by this author fall in this category. Imposing our `unconstrained initial state' condition on a deterministic theory underlying Quantum Mechanics, appears to lead to a restricted free-will condition in the quantum system: an observer has the free will to modify the setting of a measuring device, but has no control over the phase of its wave function. The dismissal of the usual "free will" concept does not have any consequences for our views and interpretations of human activities in daily life, and the way our minds function, but it requires a more careful discussion on what, in practice, free will actually amounts to.

Gerard 't Hooft

2007-01-15T23:59:59.000Z

255

Can the photosynthesis first step quantum mechanism be explained?  

E-Print Network (OSTI)

Photosynthesis first step mechanism concerns the sunlight absorption and both negative and positive charges separation. Recent and important photosynthesis literature claims that this mechanism is quantum mechanics controlled, however without presenting qualitative or quantitative scientifically based mechanism. The present accepted and old-fashioned photosynthesis mechanism model suffers from few drawbacks and an important issue is the absence of driving force for negative and positive charges separation. This article presents a new qualitative model for this first step mechanism in natural catalytic systems such as photosynthesis in green leaves. The model uses a concept of semiconductor band gap engineering, such as the staggered energy band gap line-up in semiconductors. To explain the primary mechanism in natural photosynthesis the proposal is the following: incident light is absorbed inside the leaves causing charges separation. The only energetic configuration that allows charges separation under illum...

Sacilotti, Marco; Mota, Claudia C B O; Nunes, Frederico Dias; Gomes, Anderson S L

2010-01-01T23:59:59.000Z

256

Pure state quantum statistical mechanics and black holes  

E-Print Network (OSTI)

Chapter 3 of S. Lloyd's 1988 Ph.D. thesis, `Black Holes, Demons, and the Loss of Coherence: How complex systems get information and what they do with it,' supervisor Heinz Pagels. Reformulates statistical mechanics in terms of pure states and shows that (a) quantum statistics of typical pure states are very close to the mechanics of statistical mechanical ensembles; (b) if a system is in a typical state with energy E, then the reduced density matrix of a subsystem is very close to a thermal state. (A similar result was derived using Levy's lemma some years later by S. Popescu, A.J. Short, A.Winter, Nature Physics 2, 754-758 (2006).) Pure state quantum statistical mechanics is applied to black holesto show that for typical states of matter insideand outside a black hole, the external state is likely to be thermal. Proposes novel interpretation of probabilities in quantum statistical mechanics. Full thesis available at http://meche.mit.edu/documents/slloyd_thesis.pdf. This chapter was submitted for publication to Physical Review in 1988 but rejected by one sentence referee report: `There is no physics in this paper.' You be the judge.

Seth Lloyd

2013-07-01T23:59:59.000Z

257

Maximal Beable Subalgebras of Quantum-Mechanical Observables  

E-Print Network (OSTI)

Given a state on an algebra of bounded quantum-mechanical observables (the self-adjoint part of a C*-algebra), we investigate those subalgebras that are maximal with respect to the property that the given state's restriction to the subalgebra is a mixture of dispersion-free states---what we call maximal "beable" subalgebras (borrowing a terminology due to J. S. Bell). We also extend our investigation to the theory of algebras of unbounded observables (as developed by R. Kadison), and show how our results articulate a solid mathematical foundation for central tenets of the orthodox Copenhagen interpretation of quantum theory (such as the joint indeterminacy of canonically conjugate observables, and Bohr's defense of the completeness of quantum theory against the argument of Einstein, Podolsky, and Rosen).

Hans Halvorson; Rob Clifton

1999-05-13T23:59:59.000Z

258

Thermodynamics of quantum jump trajectories in systems driven by classical fluctuations  

E-Print Network (OSTI)

The large-deviation method can be used to study the measurement trajectories of open quantum systems. For optical arrangements this formalism allows to describe the long time properties of the (non-equilibrium) photon counting statistics in the context of a (equilibrium) thermodynamic approach defined in terms of dynamical phases and transitions between them in the trajectory space [J.P. Garrahan and I. Lesanovsky, Phys. Rev. Lett. 104, 160601 (2010)]. In this paper, we study the thermodynamic approach for fluorescent systems coupled to complex reservoirs that induce stochastic fluctuations in their dynamical parameters. In a fast modulation limit the thermodynamics corresponds to that of a Markovian two-level system. In a slow modulation limit, the thermodynamic properties are equivalent to those of a finite system that in an infinite-size limit is characterized by a first-order transition. The dynamical phases correspond to different intensity regimes, while the size of the system is measured by the transition rate of the bath fluctuations. As a function of a dimensionless intensive variable, the first and second derivative of the thermodynamic potential develop an abrupt change and a narrow peak respectively. Their scaling properties are consistent with a double-Gaussian probability distribution of the associated extensive variable.

Adrian A. Budini

2010-12-03T23:59:59.000Z

259

Quantum walks: a comprehensive review  

E-Print Network (OSTI)

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important resul...

Venegas-Andraca, Salvador E

2012-01-01T23:59:59.000Z

260

Obtaining the Probability Vector Current Density in Canonical Quantum Mechanics by Linear Superposition  

E-Print Network (OSTI)

The quantum mechanics status of the probability vector current density has long seemed to be marginal. On one hand no systematic prescription for its construction is provided, and the special examples of it that are obtained for particular types of Hamiltonian operator could conceivably be attributed to happenstance. On the other hand this concept's key physical interpretation as local average particle flux, which flows from the equation of continuity that it is supposed to satisfy in conjunction with the probability scalar density, has been claimed to breach the uncertainty principle. Given the dispiriting impact of that claim, we straightaway point out that the subtle directional nature of the uncertainty principle makes it consistent with the measurement of local average particle flux. We next focus on the fact that the unique closed-form linear-superposition quantization of any classical Hamiltonian function yields in tandem the corresponding unique linear-superposition closed-form divergence of the probability vector current density. Because the probability vector current density is linked to the quantum physics only through the occurrence of its divergence in the equation of continuity, it is theoretically most appropriate to construct this vector field exclusively from its divergence -- analysis of the best-known "textbook" special example of a probability vector current density shows that it is thus constructed. That special example in fact leads to the physically interesting "Ehrenfest subclass" of probability vector current densities, which are closely related to their classical peers.

Steven Kenneth Kauffmann

2013-02-02T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Rigged Hilbert space formalism as an extended mathematical formalism for quantum systems. II. Transformation theory in nonrelativistic quantum mechanics  

Science Conference Proceedings (OSTI)

Results of a previous paper are used to obtain a rigorous mathematical formulation of the transformation theory of nonrelativistic quantum mechanics within the framework of rigged Hilbert spaces.

O. Melsheimer

1974-01-01T23:59:59.000Z

262

Brit. J. Phil. Sci. 58 (2007), 595604 Is Standard Quantum Mechanics  

E-Print Network (OSTI)

Brit. J. Phil. Sci. 58 (2007), 595­604 Is Standard Quantum Mechanics Technologically Inadequate? F]) claims to have demonstrated that standard quantum mechanics is technologically inadequate is that Vermaas' claim that standard quantum mechanics is technologically inadequate evaporates. 1 Introduction 2

Seevinck, Michiel

263

Homogeneous decoherence functionals in standard and history quantum mechanics  

E-Print Network (OSTI)

General history quantum theories are quantum theories without a globally defined notion of time. Decoherence functionals represent the states in the history approach and are defined as certain bivariate complex-valued functionals on the space of all histories. However, in practical situations -- for instance in the history formulation of standard quantum mechanics -- there often is a global time direction and the homogeneous decoherence functionals are specified by their values on the subspace of homogeneous histories. In this work we study the analytic properties of (i) the standard decoherence functional in the history version of standard quantum mechanics and (ii) homogeneous decoherence functionals in general history theories. We restrict ourselves to the situation where the space of histories is given by the lattice of projections on some Hilbert space H. Among other things we prove the non-existence of a finitely valued extension for the standard decoherence functional to the space of all histories, derive a representation for the standard decoherence functional as an unbounded quadratic form with a natural representation on a Hilbert space and prove the existence of an Isham-Linden-Schreckenberg (ILS) type representation for the standard decoherence functional.

Oliver Rudolph; J. D. M. Wright

1998-07-23T23:59:59.000Z

264

Multi-loop Feynman integrals and conformal quantum mechanics  

E-Print Network (OSTI)

New algebraic approach to analytical calculations of D-dimensional integrals for multi-loop Feynman diagrams is proposed. We show that the known analytical methods of evaluation of multi-loop Feynman integrals, such as integration by parts and star-triangle relation methods, can be drastically simplified by using this algebraic approach. To demonstrate the advantages of the algebraic method of analytical evaluation of multi-loop Feynman diagrams, we calculate ladder diagrams for the massless $\\phi^3$ theory. Using our algebraic approach we show that the problem of evaluation of special classes of Feynman diagrams reduces to the calculation of the Green functions for specific quantum mechanical problems. In particular, the integrals for ladder massless diagrams in the $\\phi^3$ scalar field theory are given by the Green function for the conformal quantum mechanics.

A. P. Isaev

2003-03-06T23:59:59.000Z

265

Classical Models of Subatomic Particles  

E-Print Network (OSTI)

We look at the program of modelling a subatomic particle---one having mass, charge, and angular momentum---as an interior solution joined to a classical general-relativistic Kerr-Newman exterior spacetime. We find that the assumption of stationarity upon which the validity of the Kerr-Newman exterior solution depends is in fact violated quantum mechanically for all known subatomic particles. We conclude that the appropriate stationary spacetime matched to any known subatomic particle is flat space.

R. B. Mann; M. S. Morris

1993-07-21T23:59:59.000Z

266

An Overview of Quantum Computing for Technology Managers  

E-Print Network (OSTI)

Faster algorithms, novel cryptographic mechanisms, and alternative methods of communication become possible when the model underlying information and computation changes from a classical mechanical model to a quantum mechanical one. Quantum algorithms perform a select set of tasks vastly more efficiently than any classical algorithm, but for many tasks it has been proved that quantum algorithms provide no advantage. The breadth of quantum computing applications is still being explored. Major application areas include security and the many fields that would benefit from efficient quantum simulation. The quantum information processing viewpoint provides insight into classical algorithmic issues as well as a deeper understanding of entanglement and other non-classical aspects of quantum physics. This overview is aimed at technology managers who wish to gain a high level understanding of quantum information processing, particularly quantum computing.

Eleanor G. Rieffel

2008-04-14T23:59:59.000Z

267

Dense wavelength multiplexing of 1550 nm QKD with strong classical channels in reconfigurable networking environments  

Science Conference Proceedings (OSTI)

To move beyond dedicated links and networks, quantum communications signals must be integrated into networks carrying classical optical channels at power levels many orders of magnitude higher than the quantum signals themselves. We demonstrate transmission of a 1550-nm quantum channel with up to two simultaneous 200-GHz spaced classical telecom channels, using ROADM (reconfigurable optical <1dd drop multiplexer) technology for multiplexing and routing quantum and classical signals. The quantum channel is used to perform quantum key distribution (QKD) in the presence of noise generated as a by-product of the co-propagation of classical channels. We demonstrate that the dominant noise mechanism can arise from either four-wave mixing or spontaneous Raman scattering, depending on the optical path characteristics as well <1S the classical channel parameters. We quantity these impairments and discuss mitigation strategies.

Rosenberg, Danna [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory; Dallmann, Nicholas [Los Alamos National Laboratory; Hughes, Richard J [Los Alamos National Laboratory; Mccabe, Kevin P [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; Tyagi, Hush T [Los Alamos National Laboratory; Peters, Nicholas A [TELCORDIA TECHNOLOGIES; Toliver, Paul [TELCORDIA TECHNOLOGIES; Chapman, Thomas E [TELCORDIA TECHNOLOGIES; Runser, Robert J [TELCORDIA TECHNOLOGIES; Mcnown, Scott R [TELCORDIA TECHNOLOGIES

2008-01-01T23:59:59.000Z

268

Classical Phase Space Density for the Relativistic Hydrogen Atom  

E-Print Network (OSTI)

Quantum mechanics is considered to arise from an underlying classical structure (``hidden variable theory'', ``sub-quantum mechanics''), where quantum fluctuations follow from a physical noise mechanism. The stability of the hydrogen ground state can then arise from a balance between Lorentz damping and energy absorption from the noise. Since the damping is weak, the ground state phase space density should predominantly be a function of the conserved quantities, energy and angular momentum. A candidate for this phase space density is constructed for ground state of the relativistic hydrogen problem of a spinless particle. The first excited states and their spherical harmonics are also considered in this framework. The analytic expression of the ground state energy can be reproduced, provided averages of certain products are replaced by products of averages. This analysis puts forward that quantum mechanics may arise from an underlying classical level as a slow variable theory, where each new quantum operator relates to a new, well separated time interval.

Th. M. Nieuwenhuizen

2005-11-15T23:59:59.000Z

269

Molecular quantum mechanical observers, symmetry, and string theory  

E-Print Network (OSTI)

The paper \\cite{Dance0601} tentatively suggested a physical picture that might underlie string theories. The string parameters $\\tau $ and $\\sigma_i $ were interpreted as spacetime dimensions which a simple quantum mechanical observer can observe, while symmetries of the relevant observer states could limit the observability of other dimensions. An atomic observer was the focus of the discussion. The present paper extends the discussion of\\cite{Dance0601} to molecular observers, including the nature of some common molecular bonds and their symmetries.

M. Dance

2010-11-29T23:59:59.000Z

270

The fundamental obscurity in quantum mechanics. Could the problem be considered universal?  

E-Print Network (OSTI)

The contemporary controversy about the fundamental obscurity in quantum mechanics keeps on the old one about the aim of science, which was between the founders of the quantum theory. The orthodox quantum mechanics could be created only at the cost of renunciation of reality as the aim of natural science. The description only of phenomena, i.e. results of observation, should not be universal if no one believes that these phenomena are manifestation of a unique reality. Such belief concerning quantum mechanics is quite unacceptable because of irremediably conflict with special relativity. Nevertheless the quantum mechanics was developed and apprehended by most physicists as a universal theory of a quantum world. This fundamental discrepancy between the essence of the orthodox quantum mechanics and its history of development and studying has resulted both to an illusion about the aim of its description among most physicists and to the consideration of its fundamental obscurity as a universal problem among experts in quantum foundation. The aim of this paper is to show that quantum phenomena can not be described universally. It is indicated that rather the Schrodinger's than Born's interpretation of the wave function is valid for description of many quantum phenomena. The fundamental obscurity with which we are faced at the description, for example, macroscopic quantum phenomena differs fundamentally from the one with which the founders of the quantum theory were faced on atomic level.

A. V. Nikulov

2010-12-20T23:59:59.000Z

271

A dynamical time operator in Dirac's relativistic quantum mechanics  

E-Print Network (OSTI)

A self-adjoint dynamical time operator is introduced in Dirac's relativistic formulation of quantum mechanics and shown to satisfy a commutation relation with the Hamiltonian analogous to that of the position and momentum operators. The ensuing time-energy uncertainty relation involves the uncertainty in the instant of time when the wave packet passes a particular spatial position and the energy uncertainty associated with the wave packet at the same time, as envisaged originally by Bohr. The instantaneous rate of change of the position expectation value with respect to the simultaneous expectation value of the dynamical time operator is shown to be the phase velocity, in agreement with de Broglie's hypothesis of a particle associated wave whose phase velocity is larger than c. Thus, these two elements of the original basis and interpretation of quantum mechanics are integrated into its formal mathematical structure. Pauli's objection is shown to be resolved or circumvented. Possible relevance to current developments in interference in time, in Zitterbewegung like effects in spintronics, grapheme and superconducting systems and in cosmology is noted.

Mariano Bauer

2009-08-19T23:59:59.000Z

272

The Schrodinger-Chetaev Equation in Bohmian Quantum Mechanics and Diffusion Mechanism for Alpha Decay, Cluster Radioactivity and Spontaneous Fission  

E-Print Network (OSTI)

In the framework of Bohmian quantum mechanics supplemented with the Chetaev theorem on stable trajectories in dynamics in the presence of dissipative forces we have shown the possibility of the classical (without tunneling) universal description of radioactive decay of heavy nuclei, in which under certain conditions so called noise-induced transition is generated or, in other words, the stochastic channel of alpha decay, cluster radioactivity and spontaneous fission conditioned by the Kramers diffusion mechanism. Based on the ENSDF database we have found the parametrized solutions of the Kramers equation of Langevin type by Alexandrov dynamic auto-regularization method (FORTRAN program REGN-Dubna). These solutions describe with high-accuracy the dependence of the half-life (decay probability) of heavy radioactive nuclei on total kinetic energy of daughter decay products. The verification of inverse problem solution in the framework of the universal Kramers description of the alpha decay, cluster radioactivity and spontaneous fission, which was based on the newest experimental data of alpha-decay of even-even super heavy nuclei (Z=114, 116, 118) have shown the good coincidence of the experimental and theoretical half-life depend upon of alpha-decay energy.

V. D. Rusov; S. Cht. Mavrodiev; M. A. Deliyergiyev

2008-10-16T23:59:59.000Z

273

Quantum Algorithms for Quantum Field Theories  

E-Print Network (OSTI)

Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We develop a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (phi-fourth theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.

Stephen P. Jordan; Keith S. M. Lee; John Preskill

2011-11-15T23:59:59.000Z

274

Quantum Algorithms for Quantum Field Theories  

E-Print Network (OSTI)

Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We develop a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (phi-fourth theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.

Jordan, Stephen P; Preskill, John

2011-01-01T23:59:59.000Z

275

Efficient classical simulation of spin networks  

E-Print Network (OSTI)

In general, quantum systems are believed to be exponentially hard to simulate using classical computers. It is in these hard cases where we hope to find quantum algorithms that provide speed up over classical algorithms. ...

Sylvester, Igor Andrade

2006-01-01T23:59:59.000Z

276

Mini-Proceedings ECT*: Speakable in quantum mechanics: atomic, nuclear and subnuclear physics tests  

E-Print Network (OSTI)

Mini-Proceedings ECT*: Speakable in quantum mechanics: atomic, nuclear and subnuclear physics tests, ECT*-Trento, 29 August - 2 September, 2011

Curceanu, C; Milotti, E

2011-01-01T23:59:59.000Z

277

Mini-Proceedings ECT*: Speakable in quantum mechanics: atomic, nuclear and subnuclear physics tests  

E-Print Network (OSTI)

Mini-Proceedings ECT*: Speakable in quantum mechanics: atomic, nuclear and subnuclear physics tests, ECT*-Trento, 29 August - 2 September, 2011

C. Curceanu; J. Marton; E. Milotti

2011-12-06T23:59:59.000Z

278

Frame transforms, star products and quantum mechanics on phase space  

E-Print Network (OSTI)

Using the notions of frame transform and of square integrable projective representation of a locally compact group $G$, we introduce a class of isometries (tight frame transforms) from the space of Hilbert-Schmidt operators in the carrier Hilbert space of the representation into the space of square integrable functions on the direct product group $G\\times G$. These transforms have remarkable properties. In particular, their ranges are reproducing kernel Hilbert spaces endowed with a suitable 'star product' which mimics, at the level of functions, the original product of operators. A 'phase space formulation' of quantum mechanics relying on the frame transforms introduced in the present paper, and the link of these maps with both the Wigner transform and the wavelet transform are discussed.

P. Aniello; V. I. Man'ko; G. Marmo

2008-02-28T23:59:59.000Z

279

Quantum irreversible process in a simple model  

E-Print Network (OSTI)

We present a very simple model of a quantum system in which an irreversible process happens. The model can be used as an example of a quantum dynamical problem in introductory courses of Quantum Mechanics or as the introduction to courses on Quantum Irreversible Processes. In both cases it will help students to build some intuition on dynamical behaviour of quantum systems consisting of many degrees of freedom beyond perturbation theory and classical thermodynamics.

Wójcik, Krzysztof Piotr

2012-01-01T23:59:59.000Z

280

A self-consistent treatment of electron transfer in the limit of strong friction via the mixed quantum classical Liouville method  

SciTech Connect

Electron transfer is investigated at the limit of strong friction. The analysis is based on the generic model of a two-state system bilinearly coupled to a harmonic bath. The dynamics is described within the framework of the mixed quantum classical Liouville (MQCL) equation, which is known to be exact for this model. In the case of zero electronic coupling, it is shown that while the dynamics of the electronic populations can be described by a Markovian quantum Smoluchowski equation, that of the electronic coherences are inherently non-Markovian. A non-Markovian modified Zusman equation is derived in the presence of electronic coupling and shown to be self-consistent in cases where the standard Zusman equation is not.

Shi Qiang [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China); Geva, Eitan [Department of Chemistry and the FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

2009-07-21T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Energy Inequalities in Quantum Field Theory  

E-Print Network (OSTI)

Quantum fields are known to violate all the pointwise energy conditions of classical general relativity. We review the subject of quantum energy inequalities: lower bounds satisfied by weighted averages of the stress-energy tensor, which may be regarded as the vestiges of the classical energy conditions after quantisation. Contact is also made with thermodynamics and related issues in quantum mechanics, where such inequalities find analogues in sharp Gaarding inequalities.

Christopher J. Fewster

2005-01-31T23:59:59.000Z

282

Quantum memories with electrically controlled storage and retrieval in an opto- and electro-mechanical cavity  

E-Print Network (OSTI)

We propose a novel scheme to realize electrically controlled quantum memories in the opto- and electro-mechanical (OEM) cavity. Combining this OEM cavity with the mechanism of Electromagnetically Induced Transparency (EIT) we find that the quantum interference, arising from the two optical transitions of the $\\Lambda$ type three-level atomic ensembles, can be manipulated electrically. Numerical calculations show that the probe photon state can be well stored into the atomic spin state by sending an electric current pulse and retrieved with time-reverse symmetry by sending the other current pulse with opposite direction. The quantum interference with electric controlling is expected to apply to other quantum control aspects.

Li-Guo Qin; Zhong-Yang Wang; Gong-Wei Lin; Jing-Yun Zhao; Shang-Qing Gong

2013-09-12T23:59:59.000Z

283

Semiclassical anomalies of the quantum mechanical systems and their modifications for the asymptotic matching  

SciTech Connect

JWKB solutions to the Initial Value Problems (IVPs) of the Time Independent Schrodinger's Equation (TISE) for the Simple Linear Potentials (SLPs) with a turning point parameter have been studied according to the turning points by graphical analysis to test the results of the JWKB solutions and suggested modifications. The anomalies happening in the classically inaccessible region where the SLP function is smaller than zero and the results of the suggested modifications, which are in consistent with the quantum mechanical theories, to remove these anomalies in this region have been presented. The origins of the anomalies and verifications of the suggested modifications showing a great success in the results have also been studied in terms of a suggested M{sub ij}=S{sup {approx}}{sub i-1,j} matrix elements made up of the JWKB expansion terms, S{sub i-1,j} (where i = 1, 2, 3 and j 1, 2). The results of the modifications for the IVPs and their application to the Bound State Problems (BSPs) with an example application of the Harmonic Oscillator (HO) have been presented and their generalization for any potential function have been discussed and classified accordingly.

Deniz, Coskun, E-mail: coskun.deniz@ege.edu.tr [Ege University, Faculty of Science, Department of Physics, Bornova 35100, Izmir (Turkey)

2011-08-15T23:59:59.000Z

284

Quantum mechanical analogue of the zeroth law of thermodynamics. (On the problem of incorporating Thermodynamics into Quantum Theory)  

E-Print Network (OSTI)

This approach to the incorporation of stochastic thermodynamics into quantum theory is based on the conception of consistent inclusion of the holistic stochastic environmental influence described by wave functions of the arbitrary vacuum, which was proposed in our paper previously. In this study, we implement the possibility of explicitly incorporating the zeroth law of stochastic thermodynamics in the form of the saturated Schr\\"odinger uncertainty relation into quantum theory. This allows comparatively analyzing the sets of states of arbitrary vacuums, namely, squeezed coherent states (SCSs) and correlated coherent states (CCSs). In addition, we compare the results of the construction of stochastic thermodynamics using SCSs and TCCSs with the versions involving the incorporation of thermodynamics into quantum theory developed previously and based on thermofield dynamics and quantum statistical mechanics.

O. N. Golubjeva; A. D. Sukhanov

2013-03-25T23:59:59.000Z

285

A General Systems Theory for Chaos, Quantum Mechanics and Gravity for Dynamical Systems of all Space-Time Scales  

E-Print Network (OSTI)

Non-local connections, i. e. long-range space-time correlations intrinsic to the observed subatomic dynamics of quantum systems is also exhibited by macro-scale dynamical systems as selfsimilar fractal space-time fluctuations and is identified as self-organized criticality. The author has developed a general systems theory for the observed self-organized criticality applicable to dynamical systems of all space-time scales based on the concept that spatial integration of enclosed small-scale fluctuations results in the formation of large eddy circulation. The eddy energy spectrum therefore represents the statistical normal distribution according to the Central Limit Theorem. The additive amplitudes of eddies, when squared (variance or eddy kinetic energy), represent the statistical normal (probability) distribution, a result observed in the subatomic dynamics of quantum systems. The model predicts Kepler's laws of planetary motion for eddy circulation dynamics. Inverse square law of gravitation therefore applies to the eddy continuum ranging from subatomic to macro-scale dynamical systems, e.g. weather systems. The model is similar to a superstring model for subatomic dynamics which unifies quantum mechanical and classical concepts and manifestation of matter is visualised as vibrational modes in string-like energy flow patterns. The cumulative sum of centripetal forces in a hierarchy of vortex circulations may result in the observed inverse square law form for gravitational attraction between inertial masses of the eddies.

A M Selvam

2005-03-03T23:59:59.000Z

286

Quantum hologram of macroscopically entangled light via the mechanism of diffuse light storage  

E-Print Network (OSTI)

In the present paper we consider a quantum memory scheme for light diffusely propagating through a spatially disordered atomic gas. The diffuse trapping of the signal light pulse can be naturally integrated with the mechanism of stimulated Raman conversion into a long-lived spin coherence. Then the quantum state of the light can be mapped onto the disordered atomic spin subsystem and can be stored in it for a relatively long time. The proposed memory scheme can be applicable for storage of the macroscopic analog of the $\\Psi^{(-)}$ Bell state and the prepared entangled atomic state performs its quantum hologram, which suggests the possibility of further quantum information processing.

L. V. Gerasimov; I. M. Sokolov; D. V. Kupriyanov; M. D. Havey

2011-11-29T23:59:59.000Z

287

The symmetry groups of noncommutative quantum mechanics and coherent state quantization  

SciTech Connect

We explore the group theoretical underpinning of noncommutative quantum mechanics for a system moving on the two-dimensional plane. We show that the pertinent groups for the system are the two-fold central extension of the Galilei group in (2+1)-space-time dimensions and the two-fold extension of the group of translations of R{sup 4}. This latter group is just the standard Weyl-Heisenberg group of standard quantum mechanics with an additional central extension. We also look at a further extension of this group and discuss its significance to noncommutative quantum mechanics. We build unitary irreducible representations of these various groups and construct the associated families of coherent states. A coherent state quantization of the underlying phase space is then carried out, which is shown to lead to exactly the same commutation relations as usually postulated for this model of noncommutative quantum mechanics.

Chowdhury, S. Hasibul Hassan; Ali, S. Twareque [Department of Mathematics and Statistics, Concordia University, Montreal, Quebec H3G 1M8 (Canada)] [Department of Mathematics and Statistics, Concordia University, Montreal, Quebec H3G 1M8 (Canada)

2013-03-15T23:59:59.000Z

288

Analytic calculation of Witten index in D= 2 supersymmetric Yang-Mills quantum mechanics  

Science Conference Proceedings (OSTI)

We evaluate analytically the Witten index of D= 2 supersymmetric Yang-Mills quantum mechanics. We rederive a known result for the SU(2) gauge group and generalize it to any SU(N) gauge group.

Korcyl, Piotr [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland)

2012-10-15T23:59:59.000Z

289

Anti-hydrogen: The cusp between quantum mechanics and general relativity  

DOE Green Energy (OSTI)

We argue that the crossing (CPT) symmetry of relativistic quantum mechanics requires that both the coulombic and the Newtonian force between pairs of particles will reverse when one is replaced by its anti-particle. For consistency, this requires a theory in which both the equivalence principles and gauge invariance are abandoned. thus whether anti-hydrogen ``falls`` up or down will provide an experiment crusis separating general relativity and gauge invariance from this version of quantum mechanics.

Noyes, H.P.

1992-09-01T23:59:59.000Z

290

Anti-hydrogen: The cusp between quantum mechanics and general relativity  

DOE Green Energy (OSTI)

We argue that the crossing (CPT) symmetry of relativistic quantum mechanics requires that both the coulombic and the Newtonian force between pairs of particles will reverse when one is replaced by its anti-particle. For consistency, this requires a theory in which both the equivalence principles and gauge invariance are abandoned. thus whether anti-hydrogen falls'' up or down will provide an experiment crusis separating general relativity and gauge invariance from this version of quantum mechanics.

Noyes, H.P.

1992-09-01T23:59:59.000Z

291

Comparison of quantum-mechanical and semiclassical approaches for an analysis of spin dynamics in quantum dots  

Science Conference Proceedings (OSTI)

Two approaches to the description of spin dynamics of electron-nuclear system in quantum dots are compared: the quantum-mechanical one is based on direct diagonalization of the model Hamiltonian and semiclassical one is based on coupled equations for precession of mean electron spin and mean spin of nuclear spin fluctuations. The comparison was done for a model problem describing periodic excitation of electron-nuclear system by optical excitation. The computation results show that scattering of parameters related to fluctuation of the nuclear spin system leads to appearance of an ordered state in the system caused by periodic excitation and to the effect of electron-spin mode locking in an external magnetic field. It is concluded that both models can qualitatively describe the mode-locking effect, however give significantly different quantitative results. This may indicate the limited applicability of the precession model for describing the spin dynamics in quantum dots in the presence of optical pumping.

Petrov, M. Yu., E-mail: m.petrov@spbu.ru; Yakovlev, S. V. [Saint Petersburg State University (Russian Federation)

2012-08-15T23:59:59.000Z

292

Quantum noise in a nano mechanical Duffing resonator  

E-Print Network (OSTI)

We determine the small signal gain and noise response of an amplifier based on the nonlinear response of a quantum nanomechanical resonator. The resonator is biased in the nonlinear regime by a strong harmonic bias force and we determine the response to a small additional driving signal detuned with respect to the bias force.

E. Babourina-Brooks; A. Doherty; G. J. Milburn

2008-04-22T23:59:59.000Z

293

Quantum error control codes  

E-Print Network (OSTI)

It is conjectured that quantum computers are able to solve certain problems more quickly than any deterministic or probabilistic computer. For instance, Shor's algorithm is able to factor large integers in polynomial time on a quantum computer. A quantum computer exploits the rules of quantum mechanics to speed up computations. However, it is a formidable task to build a quantum computer, since the quantum mechanical systems storing the information unavoidably interact with their environment. Therefore, one has to mitigate the resulting noise and decoherence effects to avoid computational errors. In this dissertation, I study various aspects of quantum error control codes - the key component of fault-tolerant quantum information processing. I present the fundamental theory and necessary background of quantum codes and construct many families of quantum block and convolutional codes over finite fields, in addition to families of subsystem codes. This dissertation is organized into three parts: Quantum Block Codes. After introducing the theory of quantum block codes, I establish conditions when BCH codes are self-orthogonal (or dual-containing) with respect to Euclidean and Hermitian inner products. In particular, I derive two families of nonbinary quantum BCH codes using the stabilizer formalism. I study duadic codes and establish the existence of families of degenerate quantum codes, as well as families of quantum codes derived from projective geometries. Subsystem Codes. Subsystem codes form a new class of quantum codes in which the underlying classical codes do not need to be self-orthogonal. I give an introduction to subsystem codes and present several methods for subsystem code constructions. I derive families of subsystem codes from classical BCH and RS codes and establish a family of optimal MDS subsystem codes. I establish propagation rules of subsystem codes and construct tables of upper and lower bounds on subsystem code parameters. Quantum Convolutional Codes. Quantum convolutional codes are particularly well-suited for communication applications. I develop the theory of quantum convolutional codes and give families of quantum convolutional codes based on RS codes. Furthermore, I establish a bound on the code parameters of quantum convolutional codes - the generalized Singleton bound. I develop a general framework for deriving convolutional codes from block codes and use it to derive families of non-catastrophic quantum convolutional codes from BCH codes. The dissertation concludes with a discussion of some open problems.

Abdelhamid Awad Aly Ahmed, Sala

2008-05-01T23:59:59.000Z

294

Analysis of mechanisms of carrier emission in the p-i-n structures with In(Ga)As quantum dots  

SciTech Connect

With the help of the photocurrent spectroscopy, the mechanism of emission of charge carriers from energy levels of the (In,Ga)As/(Al,Ga)As quantum dots of different design are studied. Thermal activation is shown to be the main mechanism of carrier emission from the quantum dots for the isolated layer of quantum dots separated by wide (Al,Ga)As spacer layers. At a small width of the (Al,Ga)As spacer layer, when electron binding of separate layers of the quantum dots in the vertical direction takes place, the role of the tunneling mechanism of carrier emission between the vertically coupled quantum dots increases.

Shatalina, E. S., E-mail: Shatalina@mail.ioffe.ru; Blokhin, S. A.; Nadtochy, A. M.; Payusov, A. S.; Savelyev, A. V.; Maximov, M. V.; Zhukov, A. E. [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation); Ledentsov, N. N. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Kovsh, A. R.; Mikhrin, S. S.; Ustinov, V. M. [Innolume GmbH (Germany)

2010-10-15T23:59:59.000Z

295

Probing mechanical quantum coherence with an ultracold-atom meter  

Science Conference Proceedings (OSTI)

We propose a scheme to probe quantum coherence in the state of a nanocantilever based on its magnetic coupling (mediated by a magnetic tip) with a spinor Bose Einstein condensate (BEC). By mapping the BEC into a rotor, its coupling with the cantilever results in a gyroscopic motion whose properties depend on the state of the cantilever: the dynamics of one of the components of the rotor angular momentum turns out to be strictly related to the presence of quantum coherence in the state of the cantilever. We also suggest a detection scheme relying on Faraday rotation, which produces only a very small back-action on the BEC and is thus suitable for a continuous detection of the cantilever's dynamics.

Lo Gullo, N.; Busch, Th. [Department of Physics, University College Cork, Cork (Ireland); Palma, G. M. [NEST Istituto Nanoscienze-CNR and Dipartimento di Fisica, Univerisita' degli Studi di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Paternostro, M. [Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN (United Kingdom)

2011-12-15T23:59:59.000Z

296

Quantum Mechanical Corrections to Simulated Shock Hugoniot Temperatures  

SciTech Connect

The authors present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a grueneisen equation of state and a quasi-harmonic approximation to the vibrational energies, they derive a simple, post-processing method for calculation of the quantum corrected Hugoniot temperatures. They have used our novel technique on ab initio simulations of both shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism and technique can be easily applied to a number of different shock compressed molecular liquids or covalent solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems.

Goldman, N; Reed, E; Fried, L E

2009-07-17T23:59:59.000Z

297

How to verify the redshift mechanism of low-energy quantum gravity  

E-Print Network (OSTI)

In the model of low-energy quantum gravity by the author, the redshift mechanism is quantum and local, and it is not connected with any expansion of the Universe. A few possibilities to verify its predictions are considered here: the specialized ground-based laser experiment; a deceleration of massive bodies and the Pioneer anomaly; a non-universal character of the Hubble diagram for soft and hard radiations; galaxy/quasar number counts.

Michael A. Ivanov

2008-09-10T23:59:59.000Z

298

The Interface between Quantum Mechanics and General Relativity  

E-Print Network (OSTI)

The generation, as well as the detection, of gravitational radiation by means of charged superfluids is considered. One example of such a "charged superfluid" consists of a pair of Planck-mass-scale, ultracold "Millikan oil drops," each with a single electron on its surface, in which the oil of the drop is replaced by superfluid helium. When levitated in a magnetic trap, and subjected to microwave-frequency electromagnetic radiation, a pair of such "Millikan oil drops" separated by a microwave wavelength can become an efficient quantum transducer between quadrupolar electromagnetic and gravitational radiation. This leads to the possibility of a Hertz-like experiment, in which the source of microwave-frequency gravitational radiation consists of one pair of "Millikan oil drops" driven by microwaves, and the receiver of such radiation consists of another pair of "Millikan oil drops" in the far field driven by the gravitational radiation generated by the first pair. The second pair then back-converts the gravitional radiation into detectable microwaves. The enormous enhancement of the conversion efficiency for these quantum transducers over that for electrons arises from the fact that there exists macroscopic quantum phase coherence in these charged superfluid systems.

Raymond Y. Chiao

2006-01-29T23:59:59.000Z

299

Quantum mechanics of graphene with a one-dimensional potential  

SciTech Connect

Electron states in graphene with a one-dimensional potential have been studied. An approximate solution has been obtained for a small angle between vectors of the incident electron momentum and potential gradient. Exactly solvable problems with a potential of the smoothened step type U(x) Utanh(x/a) and a potential with a singularity U(x) = -U/(|x| + d) are considered. The transmission/reflection coefficients and phases for various potential barriers are determined. A quasi-classical solution is obtained.

Miserev, D. S. [Novosibirsk State University (Russian Federation); Entin, M. V., E-mail: entin@isp.nsc.ru [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2012-10-15T23:59:59.000Z

300

Three approaches to classical thermal field theory  

SciTech Connect

Research Highlights: > Classical thermal field theory admits three equivalent path integral formulations. > Classical Feynman rules can be derived for all three formulations. > Quantum Feynman rules reduce to classical ones at high temperatures. > Classical Feynman rules become much simpler when superfields are introduced. - Abstract: In this paper we study three different functional approaches to classical thermal field theory, which turn out to be the classical counterparts of three well-known different formulations of quantum thermal field theory: the closed-time path (CTP) formalism, the thermofield dynamics (TFD) and the Matsubara approach.

Gozzi, E., E-mail: gozzi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, Miramare - Grignano, 34151 Trieste (Italy); INFN, Sezione di Trieste (Italy); Penco, R., E-mail: rpenco@syr.edu [Department of Physics, Syracuse University, Syracuse, NY 13244-1130 (United States)

2011-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Topological gauge theories from supersymmetric quantum mechanics on spaces of connections  

E-Print Network (OSTI)

We rederive the recently introduced $N=2$ topological gauge theories, representing the Euler characteristic of moduli spaces ${\\cal M}$ of connections, from supersymmetric quantum mechanics on the infinite dimensional spaces ${\\cal A}/{\\cal G}$ of gauge orbits. To that end we discuss variants of ordinary supersymmetric quantum mechanics which have meaningful extensions to infinite-dimensional target spaces and introduce supersymmetric quantum mechanics actions modelling the Riemannian geometry of submersions and embeddings, relevant to the projections ${\\cal A}\\rightarrow {\\cal A}/{\\cal G}$ and inclusions ${\\cal M}\\subset{\\cal A}/{\\cal G}$ respectively. We explain the relation between Donaldson theory and the gauge theory of flat connections in $3d$ and illustrate the general construction by other $2d$ and $4d$ examples.

M Blau; G Thompson

1991-12-20T23:59:59.000Z

302

Shape-invariance and Exactly Solvable Problems in Quantum Mechanics  

E-Print Network (OSTI)

Algebraic approach to the integrability condition called shape invariance is briefly reviewed. Various applications of shape-invariance available in the literature are listed. A class of shape-invariant bound-state problems which represent two-level systems are examined. These generalize the Jaynes-Cummings Hamiltonian. Coherent states associated with shape-invariant systems are discussed. For the case of quantum harmonic oscillator the decomposition of identity for these coherent states is given. This decomposition of identity utilizes Ramanujan's integral extension of the beta function.

A. B. Balantekin

2003-09-15T23:59:59.000Z

303

Quantum mechanics of one-dimensional trapped Tonks gases  

E-Print Network (OSTI)

Several experimental groups are currently working towards realizing quasi-one-dimensional (1D) atom waveguides and loading them with ultracold atoms. The dynamics becomes truly 1D in a regime (Tonks gas) of low temperatures and densities and large positive scattering lengths for which the transverse mode becomes frozen, in which case the many-body Schrodinger dynamics becomes exactly soluble via a Fermi-Bose mapping theorem. In this paper we review our recent work on the exact ground state and quantum dynamics of 1D Tonks gases and assess the possibility of approaching the Tonks regime using Bessel beam optical dipole traps.

M. D. Girardeau; E. M. Wright

2001-04-30T23:59:59.000Z

304

Quantum physics meets biology  

E-Print Network (OSTI)

Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the last decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world view of quantum coherences, entanglement and other non-classical effects, has been heading towards systems of increasing complexity. The present perspective article shall serve as a pedestrian guide to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future quantum biology, its current status, recent experimental progress and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.

Markus Arndt; Thomas Juffmann; Vlatko Vedral

2009-11-01T23:59:59.000Z

305

Quantum-Mechanical Model of Spacetime I: Microscopic Properties of Spacetime  

E-Print Network (OSTI)

This is the first part in a series of two papers, where we consider a specific microscopic model of spacetime. In our model Planck size quantum black holes are taken to be the fundamental building blocks of space and time. Spacetime is assumed to be a graph, where black holes lie on the vertices. In this first paper we construct our model in details, and show how classical spacetime emerges at the long distance limit from our model. We also consider the statistics of spacetime.

Makela, J

2008-01-01T23:59:59.000Z

306

A Simple Quantum-Mechanical Model of Spacetime I: Microscopic Properties of Spacetime  

E-Print Network (OSTI)

This is the first part in a series of two papers, where we consider a specific microscopic model of spacetime. In our model Planck size quantum black holes are taken to be the fundamental building blocks of space and time. Spacetime is assumed to be a graph, where black holes lie on the vertices. In this first paper we construct our model in details, and show how classical spacetime emerges at the long distance limit from our model. We also consider the statistics of spacetime.

J. Makela

2008-05-26T23:59:59.000Z

307

Student understanding of quantum mechanics at the beginning of graduate instruction  

Science Conference Proceedings (OSTI)

A survey was developed to probe student understanding of quantum mechanics at the beginning of graduate instruction. The survey was administered to 202 physicsgraduate students enrolled in first-year quantum mechanics courses from seven universities at the beginning of the first semester. We also conducted one-on-one interviews with fifteen graduate or advanced undergraduate students who had just completed a course in which all the content on the survey was covered. Although students from some universities performed better on average than others

Chandralekha Singh

2008-01-01T23:59:59.000Z

308

Quantum Weak Measurements and Cosmology  

E-Print Network (OSTI)

The indeterminism of quantum mechanics generally permits the independent specification of both an initial and a final condition on the state. Quantum pre-and-post-selection of states opens up a new, experimentally testable, sector of quantum mechanics, when combined with statistical averages of identical weak measurements. In this paper I apply the theory of weak quantum measurements combined with pre-and-post-selection to cosmology. Here, pre-selection means specifying the wave function of the universe or, in a popular semi-classical approximation, the initial quantum state of a subset of quantum fields propagating in a classical back-ground spacetime. The novel feature is post-selection: the additional specification of a condition on the quantum state in the far future. I discuss "natural" final conditions, and show how they may lead to potentially large and observable effects at the present cosmological epoch. I also discuss how pre-and-post-selected quantum contrast to the expectation value of the stress-energy-momentum tensor, resolving a vigorous debate from the 1970's. The paper thus provides a framework for computing large-scale cosmological effects arising from this new sector of quantum mechanics. A simple experimental test is proposed.

Paul Davies

2013-09-03T23:59:59.000Z

309

Philosophy of mind and the problem of free will in the light of quantum mechanics  

E-Print Network (OSTI)

Defects occasioned by the advent of quantum mechanics are described in detail of recent arguments by John Searle and by Jaegwon Kim pertaining to the question of the complete reducibility to the physical of the apparent capacity of a person's conscious thoughts to affect the behaviour of that person's physically described brain.

Henry P. Stapp

2008-05-01T23:59:59.000Z

310

Quantum mechanics and gravity as preclusion principles of four dimensional geometries  

E-Print Network (OSTI)

The goal of this paper is to employ a "preclusion principle" originally suggested by Rafael Sorkin in order to come up with a relativistically covariant model of quantum mechanics and gravity. Space-time is viewed as geometry as opposed to dynamics, and "unwanted" histories in that geometry are precluded.

Roman Sverdlov

2008-10-01T23:59:59.000Z

311

Quantum mechanical method of fragment's angular and energy distribution calculation for binary and ternary fission  

Science Conference Proceedings (OSTI)

In the framework of quantum-mechanical fission theory, the method of calculation for partial fission width amplitudes and asymptotic behavior of the fissile nucleus wave function with strong channel coupling taken into account has been suggested. The method allows one to solve the calculation problem of angular and energy distribution countation for binary and ternary fission.

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Titova, L. V.; Pen'kov, N. V. [Voronezh State University (Russian Federation)

2006-08-15T23:59:59.000Z

312

Philosophy of Mind and the Problem of FreeWill in the Light of Quantum Mechanics.  

Science Conference Proceedings (OSTI)

Arguments pertaining to the mind-brain connection and to the physical effectiveness of our conscious choices have been presented in two recent books, one by John Searle, the other by Jaegwon Kim. These arguments are examined, and it is argued that the difficulties encountered arise from a defective understanding and application of a pertinent part of contemporary science, namely quantum mechanics.

Stapp, Henry; Stapp, Henry P

2008-04-01T23:59:59.000Z

313

A MOLECULAR AND QUANTUM MECHANICAL STUDY OF INDOLE-3-ACETIC ACID  

E-Print Network (OSTI)

A MOLECULAR AND QUANTUM MECHANICAL STUDY OF INDOLE-3- ACETIC ACID Rudolf Kiralj (PQ) and Márcia M with simple molecular structure. All the attempts to quantify its structure-biological activity relationship were not much successful up to date, mostly due to missing knowledge about some intrinsic molecular

Ferreira, Márcia M. C.

314

The Interface between Quantum Mechanics and General Relativity  

E-Print Network (OSTI)

The generation, as well as the detection, of gravitational radiation by means of charged superfluids is considered. One example of such a "charged superfluid" consists of a pair of Planck-mass-scale, ultracold "Millikan oil drops," each with a single electron on its surface, in which the oil of the drop is replaced by superfluid helium. When levitated in a magnetic trap, and subjected to microwave-frequency electromagnetic radiation, such a pair of "Millikan oil drops" separated by a microwave wavelength can become an efficient quantum transducer between quadrupolar electromagnetic and gravitational radiation. This leads to the possibility of a Hertz-like experiment, in which the source of microwave-frequency gravitational radiation consists of one pair of "Millikan oil drops" driven by microwaves, and the receiver of such radiation consists of another pair of "Millikan oil drops" in the far field driven by the gravitational radiation generated by the first pair. The second pair then back-converts the graviti...

Chiao, R Y

2006-01-01T23:59:59.000Z

315

Quantum Computing Computer Scientists  

E-Print Network (OSTI)

Quantum Computing for Computer Scientists Noson S. Yanofsky and Mirco A. Mannucci #12;© May 2007 Noson S. Yanofsky Mirco A. Mannucci #12;Quantum Computing for Computer Scientists Noson S. Yanofsky of Vector Spaces 3 The Leap From Classical to Quantum 3.1 Classical Deterministic Systems 3.2 Classical

Yanofsky, Noson S.

316

Quantum-enhanced absorption refrigerators  

E-Print Network (OSTI)

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators.

Luis A. Correa; José P. Palao; Daniel Alonso; Gerardo Adesso

2013-08-19T23:59:59.000Z

317

Book Review of Stephen L. Adler's, "Quantum theory as an emergent phenomenon."  

E-Print Network (OSTI)

In Stephen Adler's book, "Quantum theory as an emergent phenomenon," the author starts from a classical mechanics structure and "derives" the formalism of quantum theory, together with wave function collapse dynamics, the latter providing the interpretation of quantum theory. A detailed outline of the author's argument is presented in this book review.

Philip Pearle

2006-02-07T23:59:59.000Z

318

About a possible path towards the reverse engineering of quantum mechanics  

E-Print Network (OSTI)

An out of the box intellectual path exploring the foundations of quantum mechanics is discussed in some detail, in order to clarify why a possibly different way to look at the relevant fundamental questions can be identified and can support further research. Two key concepts arise. (1) Einstein critics to quantum mechanics could be taken seriously, but ironically, in order to really do so, one would have to take seriously also some of Lorentz critics to special relativity - both in a possibly more modern way; such interconnection possibly having been a blocking factor to openly discuss some of the cross implications of alternative views about quantum mechanics to date. (2) The probabilistic interpretation is a by-product of (a) quantum evolution equations, (b) conservation laws for the combination of measuring system and measured object and (c) persistency of calibration of the measuring system - as such there is no intellectual conflict whatsoever between hidden variables theories and probabilistic interpretation, provided we consider multicomponent hidden variable models and we allow for the existence of an underlying network. The implications of such concepts, in particular for the development of a microscopic quantisation program, are heuristically discussed or preliminarily explored.

Alberto Ottolenghi

2011-11-17T23:59:59.000Z

319

Highly-efficient noise-assisted energy transport in classical oscillator systems  

E-Print Network (OSTI)

Photosynthesis is a biological process that involves the highly-efficient transport of energy captured from the sun to a reaction center, where conversion into useful biochemical energy takes place. Even though one can always use a quantum perspective to describe any physical process, since everything follows the laws of Quantum Mechanics, is the use of quantum theory imperative to explain this high efficiency? Several theoretical studies suggest that the high efficiency can only be understood as a result of the interplay between the quantum coherent evolution of the photosynthetic system, and noise introduced by its surrounding environment. Notwithstanding, we show here that noise-assisted highly-efficient energy transport can be found as well in purely classical systems; therefore, we might conclude that high efficiency energy transfer in photosynthetic systems could also be anticipated by classical models, without the need to resorting to quantum effects. Strikingly, the wider scope of applicability of the...

León-Montiel, R de J

2013-01-01T23:59:59.000Z

320

Information and The Brukner-Zeilinger Interpretation of Quantum Mechanics: A Critical Investigation  

E-Print Network (OSTI)

In Brukner and Zeilinger's interpretation of quantum mechanics, information is introduced as the most fundamental notion and the finiteness of information is considered as an essential feature of quantum systems. They also define a new measure of information which is inherently different from the Shannon information and try to show that the latter is not useful in defining the information content in a quantum object. Here, we show that there are serious problems in their approach which make their efforts unsatisfactory. The finiteness of information does not explain how objective results appear in experiments and what an instantaneous change in the so-called information vector (or catalog of knowledge) really means during the measurement. On the other hand, Brukner and Zeilinger's definition of a new measure of information may lose its significance, when the spin measurement of an elementary system is treated realistically. Hence, the sum of the individual measures of information may not be a conserved value in real experiments.

Afshin Shafiee; Feryal Safinejad; Farnoush Naqsh

2004-07-26T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Quantum Mechanical Aspects of Cell Microtubules: Science Fiction or Realistic Possibility?  

E-Print Network (OSTI)

Recent experimental research with marine algae points towards quantum entanglement at ambient temperature, with correlations between essential biological units separated by distances as long as 20 Angstr\\"oms. The associated decoherence times, due to environmental influences, are found to be of order 400 fs. This prompted some authors to connect such findings with the possibility of some kind of quantum computation taking place in these biological entities: within the decoherence time scales, the cell "quantum calculates" the optimal "path" along which energy and signal would be transported more efficiently. Prompted by these experimental results, in this talk I remind the audience of a related topic proposed several years ago in connection with the possible r\\^ole of quantum mechanics and/or field theory on dissipation-free energy transfer in microtubules (MT), which constitute fundamental cell substructures. Quantum entanglement between tubulin dimers was argued to be possible, provided there exists sufficient isolation from other environmental cell effects. The model was based on certain ferroelectric aspects of MT. In the talk I review the model and the associated experimental tests so far and discuss future directions, especially in view of the algae photo-experiments.

Nick E. Mavromatos

2010-11-29T23:59:59.000Z

322

A Quantum Mechanical Model of the Reissner-Nordstrom Black Hole  

E-Print Network (OSTI)

We consider a Hamiltonian quantum theory of spherically symmetric, asymptotically flat electrovacuum spacetimes. The physical phase space of such spacetimes is spanned by the mass and the charge parameters $M$ and $Q$ of the Reissner-Nordström black hole, together with the corresponding canonical momenta. In this four-dimensional phase space, we perform a canonical transformation such that the resulting configuration variables describe the dynamical properties of Reissner-Nordström black holes in a natural manner. The classical Hamiltonian written in terms of these variables and their conjugate momenta is replaced by the corresponding self-adjoint Hamiltonian operator, and an eigenvalue equation for the ADM mass of the hole, from the point of view of a distant observer at rest, is obtained. Our eigenvalue equation implies that the ADM mass and the electric charge spectra of the hole are discrete, and the mass spectrum is bounded below. Moreover, the spectrum of the quantity $M^2-Q^2$ is strictly positive wh...

Mäkelä, J M; Makela, Jarmo; Repo, Pasi

1998-01-01T23:59:59.000Z

323

Quantum Mechanics and CPT tests with neutral kaons at the KLOE experiment  

E-Print Network (OSTI)

Neutral kaons produced in the correlated pairs at the DAFNE phi-factory offer unique possibilities to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The analysis of the data collected by the KLOE experiment allows to improve results on several parameters describing CPT violation and decoherence and to measure the regeneration cross section on the beam pipe materials.

Izabela Balwierz-Pytko

2013-08-27T23:59:59.000Z

324

Pure States, Mixed States and Hawking Problem in Generalized Quantum Mechanics  

E-Print Network (OSTI)

This paper is the continuation of a study into the information paradox problem started by the author in his earlier works. As previously, the key instrument is a deformed density matrix in quantum mechanics of the early universe. It is assumed that the latter represents quantum mechanics with fundamental length. It is demonstrated that the obtained results agree well with the canonical viewpoint that in the processes involving black holes pure states go to the mixed ones in the assumption that all measurements are performed by the observer in a well-known quantum mechanics. Also it is shown that high entropy for Planck remnants of black holes appearing in the assumption of the Generalized Uncertainty Relations may be explained within the scope of the density matrix entropy introduced by the author previously. It is noted that the suggested paradigm is consistent with the Holographic Principle. Because of this, a conjecture is made about the possibility for obtaining the Generalized Uncertainty Relations from the covariant entropy bound at high energies in the same way as R. Bousso has derived Heisenberg uncertainty principle for the flat space.

A. E. Shalyt-Margolin

2004-05-13T23:59:59.000Z

325

Sound relativistic quantum mechanics for a strictly solitary nonzero-mass particle, and its quantum-field reverberations  

E-Print Network (OSTI)

It is generally acknowledged that neither the Klein-Gordon equation nor the Dirac Hamiltonian can produce sound solitary-particle relativistic quantum mechanics due to the ill effects of their negative-energy solutions; instead their field-quantized wavefunctions are reinterpreted as dealing with particle and antiparticle simultaneously--despite the clear physical distinguishability of antiparticle from particle and the empirically known slight breaking of the underlying CP invariance. The natural square-root Hamiltonian of the free relativistic solitary particle is iterated to obtain the Klein-Gordon equation and linearized to obtain the Dirac Hamiltonian, steps that have calculational but not physical motivation, and which generate the above-mentioned problematic negative-energy solutions as extraneous artifacts. Since the natural square root Hamiltonian for the free relativistic solitary particle contrariwise produces physically unexceptionable quantum mechanics, this article focuses on extending that Hamiltonian to describe a solitary particle (of either spin 0 or spin one-half) in relativistic interaction with an external electromagnetic field. That is achieved by use of Lorentz-covariant solitary-particle four momentum techniques together with the assumption that well-known nonrelativistic dynamics applies in the particle's rest frame. Lorentz-invariant solitary particle actions, whose formal Hamiltonization is an equivalent alternative approach, are as well explicitly displayed. It is proposed that two separate solitary-particle wavefunctions, one for a particle and the other for its antiparticle, be independently quantized in lieu of "reinterpreting" negative energy solutions--which indeed don't even afflict proper solitary particles.

Steven Kenneth Kauffmann

2009-09-22T23:59:59.000Z

326

Quantum Buckling  

E-Print Network (OSTI)

We study the mechanical buckling of a two dimensional membrane coated with a thin layer of superfluid. It is seen that a singularity (vortex or anti-vortex defect) in the phase of the quantum order parameter, distorts the membrane metric into a negative conical singularity surface, irrespective of the defect sign. The defect-curvature coupling and the observed instability is in striking contrast with classical elasticity where, the in-plane strain induced by positive (negative) disclinations is screened by a corresponding positive (negative) conical singularity surface. Defining a dimensionless ratio between superfluid stiffness and membrane bending modulus, we derive conditions under which the quantum buckling instability occurs. An ansatz for the resulting shape of the buckled membrane is analytically and numerically confirmed.

N. Upadhyaya; V. Vitelli

2011-06-23T23:59:59.000Z

327

Unified Representation of Quantum Mechanics on One-dimensional Harmonic Oscillator  

E-Print Network (OSTI)

A quantum state corresponds to a specific wave function. We adopt a new mathematical method [1] to improve Dirac's ladder operator method. A set of orthonormal wave functions will be used to associate the operator with the square matrix corresponding to it. These allow us to determine the matrix elements by using the operator relations without having to know the specific wave functions. As a result, we can get the direct results of matrix mechanics and wave mechanics on one-dimensional Harmonic oscillator and their descriptions will be also unified.

Yongqin Wang

2013-03-07T23:59:59.000Z

328

Quantum Mechanics  

Science Conference Proceedings (OSTI)

... Surprise: Photon-count-based heralding is powerful! • Highlight: Pairs, squeezing and cats. ... Highlight: Pairs, squeezing and cats. (cont.) ...

2012-09-15T23:59:59.000Z

329

Quantum Mechanics  

NLE Websites -- All DOE Office Websites (Extended Search)

Mecnica cuntica Avanzar Volver Principal ESTOY PERDIDO Considere la siguiente secuencia de ideas: Los protones y los neutrones pueden migrar por todo el interior de un...

330

Quantum scholasticism: On quantum contexts, counterfactuals, and the absurdities of quantum omniscience  

Science Conference Proceedings (OSTI)

Unlike classical information, quantum knowledge is restricted to the outcome of measurements of maximal observables corresponding to single contexts. Keywords: Context, Maximal observables, Omniscience, Quantum information

Karl Svozil

2009-02-01T23:59:59.000Z

331

Optimization Of Simulations And Activities For A New Introductory Quantum Mechanics Curriculum  

E-Print Network (OSTI)

The Institute of Physics New Quantum Curriculum (quantumphysics.iop.org) consists of online texts and interactive simulations with accompanying activities for an introductory course in quantum mechanics starting from two-level systems. We describe observation sessions and analysis of homework and survey responses used to optimize the simulations and activities in terms of clarity, ease-of-use, promoting exploration, sense-making and linking of multiple representations. This work led to revisions of simulations and activities and general design principles which have been incorporated wherever applicable. These include intuitive controls and on-demand text in the simulations and making explicit links between mathematical and physical representations in simulations and activities.

Kohnle, Antje; Hooley, Christopher; Torrance, Bruce

2013-01-01T23:59:59.000Z

332

Proposed test of relative phase as hidden variable in quantum mechanics  

E-Print Network (OSTI)

We consider the possibility that the relative phase in quantum mechanics plays a role in determining measurement outcome and could therefore serve as a "hidden" variable. The Born rule for measurement equates the probability for a given outcome with the absolute square of the coefficient of the basis state, which by design removes the relative phase from the formulation. The value of this phase at the moment of measurement naturally averages out in an ensemble, which would prevent any dependence from being observed, and we show that conventional frequency-spectroscopy measurements on discrete quantum systems cannot be imposed at a specific phase due to a straightforward uncertainty relation. We lay out general conditions for imposing measurements at a specific value of the relative phase so that the possibility of its role as a hidden variable can be tested, and we discuss implementation for the specific case of an atomic two-state system with laser-induced fluorescence for measurement.

Steven Peil

2013-02-15T23:59:59.000Z

333

Quantum fields as gravitational sources  

E-Print Network (OSTI)

The practice of setting quantum fields as sources for classical general relativity is examined. Several conceptual problems are identified which invalidate apparently innocuous equations. Alternative ways to links classical general relativity with quantum theory using Bohm's theory are proposed.

Mark J Hadley

2008-08-13T23:59:59.000Z

334

Retrocausal Effects as a Consequence of Quantum Mechanics Refined to Accommodate the Principle of Sufficient Reason  

Science Conference Proceedings (OSTI)

The principle of sufficient reason asserts that anything that happens does so for a reason: no definite state of affairs can come into being unless there is a sufficient reason why that particular thing should happen. This principle is usually attributed to Leibniz, although the first recorded Western philosopher to use it was Anaximander of Miletus. The demand that nature be rational, in the sense that it be compatible with the principle of sufficient reason, conflicts with a basic feature of contemporary orthodox physical theory, namely the notion that nature's response to the probing action of an observer is determined by pure chance, and hence on the basis of absolutely no reason at all. This appeal to pure chance can be deemed to have no rational fundamental place in reason-based Western science. It is argued here, on the basis of the other basic principles of quantum physics, that in a world that conforms to the principle of sufficient reason, the usual quantum statistical rules will naturally emerge at the pragmatic level, in cases where the reason behind nature's choice of response is unknown, but that the usual statistics can become biased in an empirically manifest way when the reason for the choice is empirically identifiable. It is shown here that if the statistical laws of quantum mechanics were to be biased in this way then the basically forward-in-time unfolding of empirical reality described by orthodox quantum mechanics would generate the appearances of backward-time-effects of the kind that have been reported in the scientific literature.

Stapp, Henry P.

2011-05-10T23:59:59.000Z

335

Radiation reaction in nonrelativistic quantum theory. [Review  

SciTech Connect

Some recent work is reviewed on the quantum theory of radiation reaction. The starting point is the Heisenberg operator equation of motion for a nonrelativistic point electron coupled to the quantized electromagnetic field. It is shown that this equation, in contrast to its classical counterpart, leads to a finite value for the electrostatic self-energy of a point electron and, for values of the fine structure constant ..cap alpha.. approximately less than 1, admits neither runaway behavior nor noncausal motion. Furthermore, the correspondence limit of the solution to the quantum mechanical equation of motion agrees with that of the Lorentz--Dirac theory in the classical regime, but without the imposition of additional conditions and with no possibility of observable noncausality. Thus, a consistent picture of a classical point electron emerges in the correspondence limit of the quantum mechanical theory. 17 references.

Sharp, D.H.

1979-01-01T23:59:59.000Z

336

The method of Hill determinants in PT-symmetric quantum mechanics  

E-Print Network (OSTI)

Hill-determinant method is described and shown applicable within the so called PT-symmetric quantum mechanics. We demonstrate that in a way paralleling its traditional Hermitian applications and proofs the method guarantees the necessary asymptotic decrease of wave functions as resulting from a fine-tuned mutual cancellation of their asymptotically growing exponential components. Technically, the rigorous proof is needed/offered that in a quasi-variational spirit the method allows us to work, in its numerical implementations, with a sequence of truncated forms of the rigorous Hill-determinant power series for the normalizable bound states.

Miloslav Znojil

2004-10-04T23:59:59.000Z

337

Mechanism for the suppression of quantum noise at large scales on expanding space  

E-Print Network (OSTI)

We present an exactly-solvable model for the suppression of quantum noise at large scales on expanding space. The suppression arises naturally in the de Broglie-Bohm pilot-wave formulation of quantum theory, according to which the Born probability rule has a dynamical origin. For a scalar field on a radiation-dominated background we construct the exact solution for the time-evolving wave functional and study properties of the associated field trajectories. It is shown that the time evolution of a field mode on expanding space is mathematically equivalent to that of a standard harmonic oscillator with a 'retarded time' that depends on the wavelength of the mode. In the far super-Hubble regime the equivalent oscillator evolves over only one Hubble time, yielding a simple mechanism whereby relaxation to the Born rule can be suppressed on very large scales. We present numerical simulations illustrating how the expansion of space can cause a retardation of relaxation in the super-Hubble regime. Given these results it is natural to expect a suppression of quantum noise at super-Hubble wavelengths. Such suppression could have taken place in a pre-inflationary era, resulting in a large-scale power deficit in the cosmic microwave background.

Samuel Colin; Antony Valentini

2013-06-07T23:59:59.000Z

338

Quantum discord in open quantum systems  

E-Print Network (OSTI)

Open quantum systems have attracted great attentions for the inevitable interaction between quantum systems and their environment would largely affect the features of interest in the systems. Quantum discord, as a measure of the total nonclassical correlation in a quantum system, includes but not only the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and it has been shown to play important roles in many fundamental physical problems and practical quantum information tasks. There have been plentiful investigations on the quantum discord and its counterpart classical correlation in open quantum systems. In this short review, we would focus on the recent development and applications of distinctive properties of quantum discord and classical correlation in open quantum systems. Several related experimental works are included.

Xu, Jin-Shi

2012-01-01T23:59:59.000Z

339

A quantum mechanical derivation of the Schwarzschild radius and its quantum correction using a model density distribution: Skin of a black hole  

E-Print Network (OSTI)

Using a single particle density distribution for a system of self-gravitating particles which ultimately forms a black hole, we from a condensed matter point of view derive the Schwarzschild radius and by including the quantum mechanical exchange energy we find a small correction to the Schwarzschild radius, which we designate as the skin of the black hole.

Subodha Mishra

2007-03-16T23:59:59.000Z

340

Connecting Blackbody Radiation, Relativity, and Discrete Charge in Classical Electrodynamics  

E-Print Network (OSTI)

It is suggested that an understanding of blackbody radiation within classical physics requires the presence of classical electromagnetic zero-point radiation, the restriction to relativistic (Coulomb) scattering systems, and the use of discrete charge. The contrasting scaling properties of nonrelativistic classical mechanics and classical electrodynamics are noted, and it is emphasized that the solutions of classical electrodynamics found in nature involve constants which connect together the scales of length, time, and energy. Indeed, there are analogies between the electrostatic forces for groups of particles of discrete charge and the van der Waals forces in equilibrium thermal radiation. The differing Lorentz- or Galilean-transformation properties of the zero-point radiation spectrum and the Rayleigh-Jeans spectrum are noted in connection with their scaling properties. Also, the thermal effects of acceleration within classical electromagnetism are related to the existence of thermal equilibrium within a gravitational field. The unique scaling and phase-space properties of a discrete charge in the Coulomb potential suggest the possibility of an equilibrium between the zero-point radiation spectrum and matter which is universal (independent of the particle mass), and an equilibrium between a universal thermal radiation spectrum and matter where the matter phase space depends only upon the ratio mc^2/kT. The observations and qualitative suggestions made here run counter to the ideas of currently accepted quantum physics.

Timothy H. Boyer

2006-04-28T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Radiation reaction in nonrelativistic quantum electrodynamics  

SciTech Connect

We derive the Heisenberg operator equation of motion for a nonrelativistic point electron coupled to the quantized electromagnetic field, including radiation reaction. The derivation proceeds in close analogy with the classical theory of extended charges (with the Compton wavelength formally playing the role of a size parameter), and we give a systematic treatment of the classical problem, showing explicitly from the equation of motion that the classical theory shows no runaway solutions or preacceleration when the electron size exceeds the classical electron radius. In the quantum-mechanical case, we show that the electrostatic self-energy of a point electron is zero and that, for values of the fine-structure constant ..cap alpha.. approximately-less-than 1, the equation of motion admits neither runaway solutions nor noncausal motion. Furthermore, the correspondence limit of the solutions to the quantum-mechanical equation of motion agrees with that of the Lorentz-Dirac theory in the classical regime, but without the imposition of additional conditions and with no possibility of observable noncausality. Thus, a consistent picture of a classical point electron emerges in the correspondence limit of the quantum-mechanical theory.

Moniz, E.J.; Sharp, D.H.

1977-05-15T23:59:59.000Z

342

A Quantum Mechanical Model of the Reissner-Nordstrom Black Hole  

E-Print Network (OSTI)

We consider a Hamiltonian quantum theory of spherically symmetric, asymptotically flat electrovacuum spacetimes. The physical phase space of such spacetimes is spanned by the mass and the charge parameters $M$ and $Q$ of the Reissner-Nordstr\\"{o}m black hole, together with the corresponding canonical momenta. In this four-dimensional phase space, we perform a canonical transformation such that the resulting configuration variables describe the dynamical properties of Reissner-Nordstr\\"{o}m black holes in a natural manner. The classical Hamiltonian written in terms of these variables and their conjugate momenta is replaced by the corresponding self-adjoint Hamiltonian operator, and an eigenvalue equation for the ADM mass of the hole, from the point of view of a distant observer at rest, is obtained. Our eigenvalue equation implies that the ADM mass and the electric charge spectra of the hole are discrete, and the mass spectrum is bounded below. Moreover, the spectrum of the quantity $M^2-Q^2$ is strictly positive when an appropriate self-adjoint extension is chosen. The WKB analysis yields the result that the large eigenvalues of the quantity $\\sqrt{M^2-Q^2}$ are of the form $\\sqrt{2n}$, where $n$ is an integer. It turns out that this result is closely related to Bekenstein's proposal on the discrete horizon area spectrum of black holes.

Jarmo Makela; Pasi Repo

1997-08-15T23:59:59.000Z

343

Quantum Mechanics of Lowest Landau Level Derived from N=4 SYM with Chemical Potential  

E-Print Network (OSTI)

The low energy effective theory of N=4 super-Yang-Mills theory on S^3 with an R-symmetry chemical potential is shown to be the lowest Landau level system. This theory is a holomorphic complex matrix quantum mechanics. When the value of the chemical potential is not far below the mass of the scalars, the states of the effective theory consist only of the half-BPS states. The theory is solved by the operator method and by utilizing the lowest Landau level projection prescription for the value of the chemical potential less than or equal to the mass of the scalars. When the chemical potential is below the mass, we find that the degeneracy of the lowest Landau level is lifted and the energies of the states are computed. The one-loop correction to the effective potential is computed for the commuting fields and treated as a perturbation to the tree level quantum mechanics. We find that the perturbation term has non-vanishing matrix elements that mix the states with the same R-charge.

D. Yamada

2005-09-28T23:59:59.000Z

344

Diagrammar in classical scalar field theory  

SciTech Connect

In this paper we analyze perturbatively a g{phi}{sup 4}classical field theory with and without temperature. In order to do that, we make use of a path-integral approach developed some time ago for classical theories. It turns out that the diagrams appearing at the classical level are many more than at the quantum level due to the presence of extra auxiliary fields in the classical formalism. We shall show that a universal supersymmetry present in the classical path-integral mentioned above is responsible for the cancelation of various diagrams. The same supersymmetry allows the introduction of super-fields and super-diagrams which considerably simplify the calculations and make the classical perturbative calculations almost 'identical' formally to the quantum ones. Using the super-diagrams technique, we develop the classical perturbation theory up to third order. We conclude the paper with a perturbative check of the fluctuation-dissipation theorem. - Highlights: > We provide the Feynman diagrams of perturbation theory for a classical field theory. > We give a super-formalism which links the quantum diagrams to the classical ones. > We check perturbatively the fluctuation-dissipation theorem.

Cattaruzza, E., E-mail: Enrico.Cattaruzza@gmail.com [Department of Physics (Miramare Campus), University of Trieste, Strada Costiera 11, Miramare-Grignano 34014, Trieste (Italy); Gozzi, E., E-mail: gozzi@ts.infn.it [Department of Physics (Miramare Campus), University of Trieste, Strada Costiera 11, Miramare-Grignano 34014, Trieste (Italy); INFN, Sezione di Trieste (Italy); Francisco Neto, A., E-mail: antfrannet@gmail.com [Departamento de Engenharia de Producao, Administracao e Economia, Escola de Minas, Campus Morro do Cruzeiro, UFOP, 35400-000 Ouro Preto MG (Brazil)

2011-09-15T23:59:59.000Z

345

Two problems in Classical Mechanics  

E-Print Network (OSTI)

A problem about the present structure of dimensional analysis, and another one about the differences between solids and fluids are suggested. Both problems appear to have certain foundational aspects.

E. E. Rosinger

2004-07-09T23:59:59.000Z

346

Molecular Quantum Mechanics 2010: From Methylene to DNA and Beyond Conference Support  

SciTech Connect

This grant was $12500 for partial support of an international conference, Molecular Quantum Mechanics 2010, which was held on the campus of the University of California, Berkeley, from 24 to 29 May 2010. The conference involved more than 250 participants. The conference schedule ran from as early as 8:00 AM to as late as 10:30 PM at night, in order to accommodate six historical lectures, 16 plenary lectures, 42 invited talks and two very strong poster sessions containing 143 contributed posters. Since 1989, the Molecular Quantum Mechanics (MQM) series of international conferences has show- cased the frontiers of research in quantum chemistry with a strong focus on basic theory and algorithms, as well as highlights of topical applications. Both were strongly in evidence at MQM 2010. At the same time as embracing the future, the MQM conferences also honour the lifetime contributions of some of the most prominent scientists in the field of theoretical and computational quantum chemistry. MQM 2010 recognised the work of Prof. Henry F. ‘Fritz’ Schaefer of the Center for Computational Chemistry at the University of Georgia, who was previously on the faculty at Berkeley The travel of invited speakers was partially covered by sponsorships from Dell Computer, Hewlett-Packard, Journal of Chemical Theory and Computation, Virginia Tech College of Science, Molecular Physics, Q-Chem Inc and the American Institute of Physics. By contrast, the conference grant from the Department of Energy was used to provide fellowships and scholarships to enable graduate students and postdoctoral fellows to attend the meeting, and thereby broaden the participation of young scientists at a meeting where in the past most of the attendees have been more senior faculty researchers. We believe that we were very successful in this regard: 118 students and postdocs attended out of the total of 256 participants. In detail, the DOE sponsorship money was partially used for dormitory scholarships that covered the cost of shared accommodation for students and postdocs at Berkeley dormitories. This covered the $200-$305 cost of a shared room for the 5-day duration of the conference. The only condition of these scholarships was that the awardee must present a poster at the meeting. Approximately $7565 was spent for these dormitory scholarships. The remaining expenditures of $4800 was used for 12 merit scholarships which were awarded to students whose poster presentations were judged the best at the conference. This amount covered a significant part of their travel and registration fees.

None

2013-05-15T23:59:59.000Z

347

Exact solution for excess electrons in quantum mechanically operating solar cells, under cumulative Auger effects  

Science Conference Proceedings (OSTI)

We derive excess carrier populations in quantum wells, embedded in the intrinsic region of p-i-n solar cells. In the process of the analysis, we (a) solve for photo-generated carriers in quantum wells and (b) determine explicit dependence on incident ... Keywords: Auger recombination, material growth, quantum photovoltaics, quantum wells, solar cells, solar spectrum

Argyrios Varonides; Robert Spalletta; Andrew Berger

2007-07-01T23:59:59.000Z

348

Quantum discord and other measures of quantum correlation  

E-Print Network (OSTI)

One of the best signatures of nonclassicality in a quantum system is the existence of correlations that have no classical counterpart. Different methods for quantifying the quantum and classical parts of the correlations are amongst the most actively-studied topics of quantum information theory in the past decade. Entanglement is the most prominent of these correlations, but in many cases unentangled states exhibit nonclassical behavior. Thus distinguishing quantum correlation other than entanglement provides a better division between the quantum and classical worlds, especially when considering mixed states. Here we review different notions of classical and quantum correlations quantified by quantum discord and other related measures. In the first half we review the mathematical properties of the measures of quantum correlation, relate them to each other, and discuss the classical-quantum division that is common among them. In the second half, we show that the measures quantum correlation identify and quanti...

Modi, Kavan; Cable, Hugo; Paterek, Tomasz; Vedral, Vlatko

2011-01-01T23:59:59.000Z

349

Simulation Of Wave Function And Probability Density Of Modified Poschl Teller Potential Derived Using Supersymmetric Quantum Mechanics  

Science Conference Proceedings (OSTI)

SUSY quantum mechanics can be applied to solve Schrodinger equation for high dimensional system that can be reduced into one dimensional system and represented in lowering and raising operators. Lowering and raising operators can be obtained using relationship between original Hamiltonian equation and the (super) potential equation. In this paper SUSY quantum mechanics is used as a method to obtain the wave function and the energy level of the Modified Poschl Teller potential. The graph of wave function equation and probability density is simulated by using Delphi 7.0 programming language. Finally, the expectation value of quantum mechanics operator could be calculated analytically using integral form or probability density graph resulted by the programming.

Angraini, Lily Maysari [STKIP Hamzanwadi Selong East Lombok, NTB, PostGraduate student at Physics Department UNS, Jl. Ir. Sutami 36 A, Surakarta (Indonesia); Suparmi,; Variani, Viska Inda [Physics Department UNS, Jl. Ir. Sutami 36 A, Surakarta (Indonesia)

2010-12-23T23:59:59.000Z

350

Non-locality and Classical Communication of the Hidden Variable Theories, arXiv: quant-ph/0511009  

E-Print Network (OSTI)

In all local realistic theories worked out till now, locality is considered as a basic assumption. Most people in the field consider the inconsistency between local realistic theories and quantum mechanics to be a result of non-local nature of quantum mechanics. In this paper, we derive Bell’s inequality for particles with instantaneous interactions, and show that the aforementioned contradiction still exists between quantum mechanics and non-local hidden variable models. Then, we use this non-locality to obtain the GHZ theorem. In what follows, we show that Bacon and Toner’s protocol, for the simulation of Bell correlation, by using local hidden variables augmented by classical communication, have some inconsistency with quantum mechanics. Our approach can answer to Brassard questions from another viewpoint, we show that if we accept that our nature obeys quantum mechanical laws, then all of quantum mechanic results cannot be simulated by realistic theories augmented by classical communication or a single instance use of non-local box.

A. Fahmi

2005-01-01T23:59:59.000Z

351

Mechanism for the suppression of quantum noise at large scales on expanding space  

E-Print Network (OSTI)

We present an exactly-solvable model for the suppression of quantum noise at large scales on expanding space. The suppression arises naturally in the de Broglie-Bohm pilot-wave formulation of quantum theory, according to which the Born probability rule has a dynamical origin. For a scalar field on a radiation-dominated background we construct the exact solution for the time-evolving wave functional and study properties of the associated field trajectories. It is shown that the time evolution of a field mode on expanding space is mathematically equivalent to that of a standard harmonic oscillator with a 'retarded time' that depends on the wavelength of the mode. In the far super-Hubble regime the equivalent oscillator evolves over only one Hubble time, yielding a simple mechanism whereby relaxation to the Born rule can be suppressed on very large scales. We present numerical simulations illustrating how the expansion of space can cause a retardation of relaxation in the super-Hubble regime. Given these results...

Colin, Samuel

2013-01-01T23:59:59.000Z

352

Strong Coupling of a Single Microwave Photon to a Superconducting Qubit Using Circuit Quantum Electrodynamics  

E-Print Network (OSTI)

commonly emitted by lasers and light bulbs have extremely feeble energy (a small night light emits torrent for developing quantum computers. Classically, light consists of waves, but quantum mechanically its energy the atom at the speed of light never to return. After several decades of dedicated effort, atomic

Devoret, Michel H.

353

Quantum Mechanics of Insitu Synthesis of Inorganic Nanoparticles with in Anionic Microgels  

E-Print Network (OSTI)

In this work, we discuss the quantum mechanics of many-body systems i.e. hybrid microgel consisting of negatively charged anionic microgels possessing thick sheath of water molecules solvating its protruding anionic moieties and nanoparticle captivated with in it. Thermodynamic feasibility of synthesis of particular nanoparticle with in the microgel is dependent upon the magnitude of interaction between nanoparticle, water molecules and microgel relative to sum of magnitude of self-interaction between counterions and interaction between counterions and microgel. Nanoparticles synthesized with in the microgels have thick electronic cloud that oscillates under the influence of net interaction potential of charged anionic moieties and solvent water molecules. Hamiltonian describing energy of oscillating electronic cloud wrapped around nanoparticle is mathematically derived to be equal to product of integral of electron density and its position vector overall space multiplied with net electric force acting on the oscillating electronic cloud of nanoparticle.

Mirza Wasif Baig; Muhammad Siddiq

2013-05-28T23:59:59.000Z

354

A quantum mechanical model for the relationship between stock price and stock ownership  

SciTech Connect

The trade of a fixed stock can be regarded as the basic process that measures its momentary price. The stock price is exactly known only at the time of sale when the stock is between traders, that is, only in the case when the owner is unknown. We show that the stock price can be better described by a function indicating at any moment of time the probabilities for the possible values of price if a transaction takes place. This more general description contains partial information on the stock price, but it also contains partial information on the stock owner. By following the analogy with quantum mechanics, we assume that the time evolution of the function describing the stock price can be described by a Schroedinger type equation.

Cotfas, Liviu-Adrian [Faculty of Economic Cybernetics, Statistics and Informatics, Academy of Economic Studies, 6 Piata Romana, 010374 Bucharest (Romania)

2012-11-01T23:59:59.000Z

355

A quantum mechanical model for the relationship between stock price and stock ownership  

E-Print Network (OSTI)

The trade of a fixed stock can be regarded as the basic process that measures its momentary price. The stock price is exactly known only at the time of sale when the stock is between traders, that is, only in the case when the owner is unknown. We show that the stock price can be better described by a function indicating at any moment of time the probabilities for the possible values of price if a transaction takes place. This more general description contains partial information on the stock price, but it also contains partial information on the stock owner. By following the analogy with quantum mechanics, we assume that the time evolution of the function describing the stock price can be described by a Schrodinger type equation.

Liviu-Adrian Cotfas

2012-07-14T23:59:59.000Z

356

The dispersion interaction between quantum mechanics and effective fragment potential molecules  

SciTech Connect

A method for calculating the dispersion energy between molecules modeled with the general effective fragment potential (EFP2) method and those modeled using a full quantum mechanics (QM) method, e.g., Hartree-Fock (HF) or second-order perturbation theory, is presented. C6 dispersion coefficients are calculated for pairs of orbitals using dynamic polarizabilities from the EFP2 portion, and dipole integrals and orbital energies from the QM portion of the system. Dividing by the sixth power of the distance between localized molecular orbital centroids yields the first term in the commonly employed London series expansion. A C8 term is estimated from the C6 term to achieve closer agreement with symmetry adapted perturbation theory values. Two damping functions for the dispersion energy are evaluated. By using terms that are already computed during an ordinary HF or EFP2 calculation, the new method enables accurate and extremely rapid evaluation of the dispersion interaction between EFP2 and QM molecules.

Smith, Quentin A.; Ruedenberg, Klaus; Gordon, Mark S.; Slipchenko, Lyudmila

2012-06-26T23:59:59.000Z

357

Quantum-mechanical model of the Kerr-Newman black hole  

E-Print Network (OSTI)

We consider a Hamiltonian quantum theory of stationary spacetimes containing a Kerr-Newman black hole. The physical phase space of such spacetimes is just six-dimensional, and it is spanned by the mass $M$, the electric charge $Q$ and angular momentum $J$ of the hole, together with the corresponding canonical momenta. In this six-dimensional phase space we perform a canonical transformation such that the resulting configuration variables describe the dynamical properties of Kerr-Newman black holes in a natural manner. The classical Hamiltonian written in terms of these variables and their conjugate momenta is replaced by the corresponding self-adjoint Hamiltonian operator and an eigenvalue equation for the Arnowitt-Deser-Misner (ADM) mass of the hole, from the point of view of a distant observer at rest, is obtained. In a certain very restricted sense, this eigenvalue equation may be viewed as a sort of "Schr\\"odinger equation of black holes". Our "Schr\\"odinger equation" implies that the ADM mass, electric charge and angular momentum spectra of black holes are discrete, and the mass spectrum is bounded from below. Moreover, the spectrum of the quantity $M^2-Q^2-a^2$, where $a$ is the angular momentum per unit mass of the hole, is strictly positive when an appropriate self-adjoint extension is chosen. The WKB analysis yields the result that the large eigenvalues of $M$, $Q$ and $a$ are of the form $\\sqrt{2n}$, where $n$ is an integer. It turns out that this result is closely related to Bekenstein's proposal on the discrete horizon area spectrum of black holes.

J. Makela; P. Repo; M. Luomajoki; J. Piilonen

2000-12-15T23:59:59.000Z

358

Complementarity and Entanglement in Quantum Information Theory  

E-Print Network (OSTI)

The restrictions that nature places on the distribution of correlations in a multipartite quantum system play fundamental roles in the evolution of such systems, and yield vital insights into the design of protocols for the quantum control of ensembles with potential applications in the field of quantum computing. We show how this entanglement sharing behavior may be studied in increasingly complex systems of both theoretical and experimental significance and demonstrate that entanglement sharing, as well as other unique features of entanglement, e.g. the fact that maximal information about a multipartite quantum system does not necessarily entail maximal information about its component subsystems, may be understood as specific consequences of the phenomenon of complementarity extended to composite quantum systems. We also present a local hidden-variable model supplemented by an efficient amount of classical communication that reproduces the quantum-mechanical predictions for the entire class of Gottesman-Kni...

Tessier, T E

2004-01-01T23:59:59.000Z

359

Quantum chaology Michael Berry  

E-Print Network (OSTI)

1 Quantum chaology Michael Berry Physics Department, University of Bristol Physics pp104-5 of Quantum: a guide for the perplexed by Jim Al-Khalili (Weidenfeld and Nicolson 2003) The quantum world appears very different from the world of classical physics that it superseded. Quantum energy levels

Berry, Michael Victor

360

QUANTUM GROUPS JOHAN KUSTERMANS  

E-Print Network (OSTI)

QUANTUM GROUPS JOHAN KUSTERMANS Syllabus: #15; The de#12;nition of a locally compact quantum group: motivational ex- amples and special cases. The classical case, compact and discrete quantum groups. #15 for weights. #15; The general de#12;nition of a locally compact quantum group and its basic consequences

Schürmann, Michael

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Quantum Signatures of Spacetime Graininess Quantum Signatures of Spacetime  

E-Print Network (OSTI)

Quantum Signatures of Spacetime Graininess Quantum Signatures of Spacetime "Graininess" Sachindeo September 2009 #12;Quantum Signatures of Spacetime Graininess Introduction 1 Length scales in physics 2 Spacetime noncommutativity from quantum uncertainties 3 Quantum Mechanics on Noncommutative Spacetime 4

362

Deformed Woods-Saxon Potential in the Frame of Supersymmetric Quantum Mechanics for Any l-State  

E-Print Network (OSTI)

A novel analytically solvable deformed Woods-Saxon potential is investigated by means of the Supersymmetric Quantum Mechanics. Hamiltonian hierarchy method and the shape invariance property are used in the calculations. The energy levels are obtained for any l-state. The interrelations for some nuclear scattering processes are also discussed

Cuneyt Berkdemir; Ayse Berkdemir; Ramazan Sever

2005-02-15T23:59:59.000Z

363

Quantum discord  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum discord Quantum discord 1663 Los Alamos science and technology magazine Latest Issue:November 2013 All Issues » submit Quantum discord A distinguishing aspect of quantum mechanics discovered at Los Alamos that may be critical to building a quantum computer March 25, 2013 Spinning coins turning into binary numbers Quantum computing Quantum computing can be carried out without the delicate entanglement of qubits previously believed to be necessary Quantum computing, in which quantum bits of information (or qubits) juggle a "superposition" of multiple values simultaneously, offers to unleash tremendous computational power if the qubits can be effectively isolated to prevent decoherence: information describing quantum states dispersing into the environment. But recent research has shown that quantum computing can be carried out

364

Dark Energy from Quantum Uncertainty of Simultaneity  

E-Print Network (OSTI)

The observed acceleration expansion of the universe was thought attribute to a mysterious dark energy in the framework of the classical general relativity. The dark energy behaves very similar with a vacuum energy in quantum mechanics. However, once the quantum effects are seriously taken into account, it predicts a wrong order of the vacuum energy and leads to a severe fine-tuning, known as the cosmological constant problem. We abandon the standard interpretation that time is a global parameter in quantum mechanics, replace it by a quantum dynamical variable playing the role of an operational quantum clock system. In the framework of reinterpretation of time, we find that the synchronization of two quantum clocks distance apart can not be realized in all rigor at quantum level. Thus leading to an intrinsic quantum uncertainty of simultaneity between spatial interval, which implies a visional vacuum energy fluctuation and gives an observed dark energy density $\\rho_{de}=\\frac{6}{\\pi}L_{P}^{-2}L_{H}^{-2}$, where $L_{P}$ and $L_{H}$ are the Planck and Hubble scale cut-off. The expectation value of zero-point energy automatically vanishes under the quantum dynamical time variable. The fraction of the dark energy is precisely given by $\\Omega_{de}=\\frac{2}{\\pi}$, which does not evolve with the quantum dynamical time variable, so it is "always" comparable to the matter energy density or the critical density. This theory is consistent with current cosmic observations.

M. J. Luo

2014-01-11T23:59:59.000Z

365

Calculation of the electron two slit experiment using a quantum mechanical variational principle  

SciTech Connect

A nonlocal relativistic variational principle (VP) has recently been proposed as an alternative to the Dirac wave equation of standard quantum mechanics. We apply that principle to the electron two-slit experiment. The detection system is modelled as a screen made of atoms, any one of which can be excited by the incident electron, but we avoid restricting the detection mechanism further. The VP is shown to predict that, at the time the electron reaches the screen, its wavefunction will be localized to the neighborhood of a single atom, resulting in a position-type measurement. In an ensemble of such experiments ('identically prepared' except that the initial phase of the wavefunction - the hidden variable in the VP formulation - is sampled over the expected uniform distribution), the distribution of measured positions will reproduce the interference pattern predicted by the Dirac equation. We also demonstrate that with a detection system designed fundamentally to detect the electron's transverse wavelength rather than its position, the VP predicts that one such mode will be detected, that is, a wavelength measurement will result. Finally, it is shown that these results are unchanged in the 'delayed choice' variant of the experiment.

Harrison, Alan K. [Los Alamos National Laboratory

2012-04-17T23:59:59.000Z

366

The Propagation of Quantum Information Through a Spin System  

E-Print Network (OSTI)

It has been recently suggested that the dynamics of a quantum spin system may provide a natural mechanism for transporting quantum information. We show that one dimensional rings of qubits with fixed (time-independent) interactions, constant around the ring, allow high fidelity communication of quantum states. We show that the problem of maximising the fidelity of the quantum communication is related to a classical problem in fourier wave analysis. By making use of this observation we find that if both communicating parties have access to limited numbers of qubits in the ring (a fraction that vanishes in the limit of large rings) it is possible to make the communication arbitrarily good.

Tobias J. Osborne; Noah Linden

2003-12-16T23:59:59.000Z

367

From permanence to total availability: a quantum conceptual upgrade  

E-Print Network (OSTI)

We consider the classical concept of time of permanence and observe that its quantum equivalent is described by a bona fide self-adjoint operator. Its interpretation, by means of the spectral theorem, reveals that we have to abandon not only the idea that quantum entities would be characterizable in terms of spatial trajectories but, more generally, that they would possess the very attribute of spatiality. Consequently, a permanence time shouldn't be interpreted as a "time" in quantum mechanics, but as a measure of the total availability of a quantum entity in participating to a creative process of spatial localization.

de Bianchi, Massimiliano Sassoli

2010-01-01T23:59:59.000Z

368

Quantum Interference in Plasmonic Circuits  

E-Print Network (OSTI)

Surface plasmon polaritons (plasmons) are a combination of light and a collective oscillation of the free electron plasma at metal-dielectric interfaces. This interaction allows sub-wavelength confinement of light, beyond the diffraction limit inherent to dielectric structures. The resulting electromagnetic fields are more intense and the strength of optical interactions between metallic structures and light-sources or detectors can be increased. Plasmons maintain non-classical photon statistics and preserve entanglement on plasmon-assisted transmission through thin, patterned metallic films or weakly confining waveguides. For quantum applications it is essential that plasmons behave as indistinguishable quantum particles. Here we report on a quantum interference experiment in a nanoscale plasmonic circuit consisting of an on-chip plasmon beam splitter with integrated superconducting single-photon detectors to allow efficient single plasmon detection. We demonstrate quantum mechanical interaction between pair...

Heeres, Reinier W; Zwiller, Valery

2013-01-01T23:59:59.000Z

369

Quantum Thermodynamics  

E-Print Network (OSTI)

Quantum thermodynamics addresses the emergence of thermodynamical laws from quantum mechanics. The link is based on the intimate connection of quantum thermodynamics with the theory of open quantum systems. Quantum mechanics inserts dynamics into thermodynamics giving a sound foundation to finite-time-thermodynamics. The emergence of the 0-law I-law II-law and III-law of thermodynamics from quantum considerations is presented. The emphasis is on consistence between the two theories which address the same subject from different foundations. We claim that inconsistency is the result of faulty analysis pointing to flaws in approximations.

Ronnie Kosloff

2013-05-10T23:59:59.000Z

370

Classical two-slit interference effects in double photoionization of molecular hydrogen at high energies  

DOE Green Energy (OSTI)

Recent experiments on double photoionization of H$_2$ with photon energies between 160 and 240 eV have revealed body-frame angular distributions that suggest classical two-slit interference effects may be present when one electron carries most of the available energy and the second electron is not observed. We report precise quantum mechanical calculations that reproduce the experimental findings. They reveal that the interpretation in terms of classical diffraction is only appropriate atsubstantially higher photon energies. At the energies considered in the experiment we offer an alternative explanation based on the mixing of two non-diffractive contributions by circularly polarized light.

Horner, Daniel A.; Miyabe, Shungo; Rescigno, Thomas N; McCurdy, C. William; Morales, Felipe; Martin, Fernando

2008-07-06T23:59:59.000Z

371

Quantum Money from Hidden Subspaces  

E-Print Network (OSTI)

Forty years ago, Wiesner pointed out that quantum mechanics raises the striking possibility of money that cannot be counterfeited according to the laws of physics. We propose the first quantum money scheme that is (1) public-key, meaning that anyone can verify a banknote as genuine, not only the bank that printed it, and (2) cryptographically secure, under a "classical" hardness assumption that has nothing to do with quantum money. Our scheme is based on hidden subspaces, encoded as the zero-sets of random multivariate polynomials. A main technical advance is to show that the "black-box" version of our scheme, where the polynomials are replaced by classical oracles, is unconditionally secure. Previously, such a result had only been known relative to a quantum oracle (and even there, the proof was never published). Even in Wiesner's original setting -- quantum money that can only be verified by the bank -- we are able to use our techniques to patch a major security hole in Wiesner's scheme. We give the first private-key quantum money scheme that allows unlimited verifications and that remains unconditionally secure, even if the counterfeiter can interact adaptively with the bank. Our money scheme is simpler than previous public-key quantum money schemes, including a knot-based scheme of Farhi et al. The verifier needs to perform only two tests, one in the standard basis and one in the Hadamard basis -- matching the original intuition for quantum money, based on the existence of complementary observables. Our security proofs use a new variant of Ambainis's quantum adversary method, and several other tools that might be of independent interest.

Scott Aaronson; Paul Christiano

2012-03-21T23:59:59.000Z

372

A Transformation Method to Construct Family of Exactly Solvable Potentials in Quantum Mechanics  

E-Print Network (OSTI)

A transformation method is applied to the second order ordinary differential equation satisfied by orthogonal polynomials to construct a family of exactly solvable quantum systems in any arbitrary dimensional space. Using the properties of orthogonal polynomials, the method transforms polynomial differential equation to D-dimensional radial Schrodinger equation which facilitates construction of exactly solvable quantum systems. The method is also applied using associated Laguerre and Hypergeometric polynomials. The quantum systems generated from other polynomials are also briefly highlighted.

Nabaratna Bhagawati; N Saikia; N Nimai Singh

2013-08-26T23:59:59.000Z

373

Interpretive Themes in Quantum Physics: Curriculum Development and Outcomes  

E-Print Network (OSTI)

A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our prior work has shown that student perspectives on the physical interpretation of quantum mechanics can be characterized, and are differentially influenced by the myriad ways instructors approach interpretive themes in their introductory courses. We report how a transformed modern physics curriculum (recently implemented at the University of Colorado) has positively impacted student perspectives on quantum physics, by making questions of classical and quantum reality a central theme of the course, but also by making the beliefs of students (and not just those of scientists) an explicit topic of discussion.

Charles Baily; Noah D. Finkelstein

2011-08-26T23:59:59.000Z

374

Interpretive Themes in Quantum Physics: Curriculum Development and Outcomes  

E-Print Network (OSTI)

A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our prior work has shown that student perspectives on the physical interpretation of quantum mechanics can be characterized, and are differentially influenced by the myriad ways instructors approach interpretive themes in their introductory courses. We report how a transformed modern physics curriculum (recently implemented at the University of Colorado) has positively impacted student perspectives on quantum physics, by making questions of classical and quantum reality a central theme of the course, but also by making the beliefs of students (and not just those of scientists) an explicit topic of discussion.

Baily, Charles

2011-01-01T23:59:59.000Z

375

Atom-light crystallization of Bose-Einstein condensates in multimode cavities: Nonequilibrium classical and quantum phase transitions, emergent lattices, supersolidity, and frustration  

Science Conference Proceedings (OSTI)

The self-organization of a Bose-Einstein condensate (BEC) in a transversely pumped optical cavity is a process akin to crystallization: when pumped by a laser of sufficient intensity, the coupled matter and light fields evolve, spontaneously, into a spatially modulated pattern, or crystal, whose lattice structure is dictated by the geometry of the cavity. In cavities having multiple degenerate modes, the quasicontinuum of possible lattice arrangements, and the continuous symmetry breaking associated with the adoption of a particular lattice arrangement, give rise to phenomena such as phonons, defects, and frustration, which have hitherto been unexplored in ultracold atomic settings involving neutral atoms. The present work develops a nonequilibrium field-theoretic approach to explore the self-organization of a BEC in a pumped, lossy optical cavity. We find that the transition is well described, in the regime of primary interest, by an effective equilibrium theory. At nonzero temperatures, the self-organization occurs via a fluctuation-driven first-order phase transition of the Brazovskii class; this transition persists to zero temperature and crosses over into a quantum phase transition. We make further use of our field-theoretic description to investigate the role of nonequilibrium fluctuations in the self-organization transition, as well as to explore the nucleation of ordered-phase droplets, the nature and energetics of topological defects, supersolidity in the ordered phase, and the possibility of frustration controlled by the cavity geometry. In addition, we discuss the range of experimental parameters for which we expect the phenomena described here to be observable, along with possible schemes for detecting ordering and fluctuations via either atomic correlations or the correlations of the light emitted from the cavity.

Gopalakrishnan, Sarang; Goldbart, Paul M. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Lev, Benjamin L. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States)

2010-10-15T23:59:59.000Z

376

Life and Quantum Biology, an Interdisciplinary Approach  

E-Print Network (OSTI)

The rapidly increasing interest in the quantum properties of living matter stimulates a discussion of the fundamental properties of life as well as quantum mechanics. In this discussion often concepts are used that originate in philosophy and ask for a philosophical analysis. In the present work the classic philosophical tradition based on Aristotle and Aquinas is employed which surprisingly is able to shed light on important aspects. Especially one could mention the high degree of unity in living objects and the occurrence of thorough qualitative changes. The latter are outside the scope of classical physics where changes are restricted to geometrical rearrangement of microscopic particles. A challenging approach is used in the philosophical analysis as the empirical evidence is not taken from everyday life but from 20th century science (quantum mechanics) and recent results in the field of quantum biology. In the discussion it is argued that quantum entanglement is possibly related to the occurrence of life. Finally it is recommended that scientists and philosophers should be open for dialogue that could enrich both. Scientists could redirect their investigation, as paradigm shifts like the one originating from philosophical evaluation of quantum mechanics give new insight about the relation between the whole en the parts. Whereas philosophers could use scientific results as a consistency check for their philosophical framework for understanding reality.

Alfred Driessen

2011-09-12T23:59:59.000Z

377

Quantum transducers: Integrating Transmission Lines and Nanomechanical Resonators via Charge Qubits  

E-Print Network (OSTI)

We propose a mechanism to interface a transmission line resonator (TLR) with a nano-mechanical resonator (NAMR) by commonly coupling them to a charge qubit, a Cooper pair box with a controllable gate voltage. Integrated in this quantum transducer or simple quantum network, the charge qubit plays the role of a controllable quantum node coherently exchanging quantum information between the TLR and NAMR. With such an interface, a maser-like process is predicted to create a quasi-classical state of the NAMR by controlling a single-mode classical current in the TLR. Alternatively, a "Cooper pair" coherent output through the transmission line can be driven by a single-mode classical oscillation of the NAMR.

C. P. Sun; L. F. Wei; Yu-xi Liu; Franco Nori

2005-04-08T23:59:59.000Z

378

Relativity in binary systems as root of quantum mechanics and space-time  

E-Print Network (OSTI)

Inspired by Bohr's dictum that "physical phenomena are observed relative to different experimental setups", this article investigates the notion of relativity in Bohr's sense, starting from a set of binary elements. The most general form of information coding within such sets requires a description by four-component states. By using Bohr's dictum as a guideline a quantum mechanical description of the set is obtained in the form of a SO(3,2) based spin network. For large (macroscopic) sub-networks a flat-space approximation of SO(3,2) leads to a Poincare symmetrical Hilbert space. The concept of a position of four-component spinors relative to macroscopic sub-networks then delivers the description of 'free' massive spin-1/2 particles with a Poincare symmetrical Hilbert space. Hence Minkowskian space-time, equipped with spin-1/2 particles, is obtained as an inherent property of a system of binary elements when individual elements are described relative to macroscopic sub-systems.

W. Smilga

2004-08-14T23:59:59.000Z

379

Reduction of Lie-Jordan algebras: Classical  

E-Print Network (OSTI)

In this paper we present a unified algebraic framework to discuss the reduction of classical and quantum systems. The underlying algebraic structure is a Lie-Jordan algebra supplemented, in the quantum case, with a Banach structure. We discuss the reduction by symmetries, by constraints as well as the possible, non trivial, combinations of both. We finally introduce a new, general framework to perform the reduction of physical systems in an algebraic setup.

F. Falceto; L. Ferro; A. Ibort; G. Marmo

2013-09-16T23:59:59.000Z

380

Quantum network coding for quantum repeaters  

E-Print Network (OSTI)

This paper considers quantum network coding, which is a recent technique that enables quantum information to be sent on complex networks at higher rates than by using straightforward routing strategies. Kobayashi et al. have recently showed the potential of this technique by demonstrating how any classical network coding protocol gives rise to a quantum network coding protocol. They nevertheless primarily focused on an abstract model, in which quantum resource such as quantum registers can be freely introduced at each node. In this work, we present a protocol for quantum network coding under weaker (and more practical) assumptions: our new protocol works even for quantum networks where adjacent nodes initially share one EPR-pair but cannot add any quantum registers or send any quantum information. A typically example of networks satisfying this assumption is {\\emph{quantum repeater networks}}, which are promising candidates for the implementation of large scale quantum networks. Our results thus show, for the...

Satoh, Takahiko; Imai, Hiroshi

2012-01-01T23:59:59.000Z

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381

Time-Energy Measure for Quantum Processes  

E-Print Network (OSTI)

Quantum mechanics sets limits on how fast quantum processes can run given some system energy through time-energy uncertainty relations, and they imply that time and energy are tradeoff against each other. Thus, we propose to measure the time-energy as a single unit for quantum channels. We consider a time-energy measure for quantum channels and compute lower and upper bounds of it using the channel Kraus operators. For a special class of channels (which includes the depolarizing channel), we can obtain the exact value of the time-energy measure. One consequence of our result is that erasing quantum information requires $\\sqrt{(n+1)/n}$ times more time-energy resource than erasing classical information, where $n$ is the system dimension.

Chi-Hang Fred Fung; H. F. Chau

2013-05-24T23:59:59.000Z

382

Quantum Feedback Networks John Gough,Wales  

E-Print Network (OSTI)

Quantum Feedback Networks John Gough,Wales Matt James,ANU #12;· Quantum Feedback · Quantum Networks - I · Classical Electrical Networks · Quantum Networks - II · Examples in Quantum Control Outline #12;· J. Gough and M.R. James, The Series Product and Its Application to Quantum Feedforward and Feedback

James, Matthew

383

A quantum mechanical look at time travel and free will Daniel Greenberger  

E-Print Network (OSTI)

, City College of the City University of New York, New York, NY 10031, USA Karl Svozil Institute://tph.tuwien.ac.at/~svozil 1 #12;I. CLASSICAL PART 1. Principle of self-consistency An irreducible, atomic physical phenomenon

Svozil, Karl

384

Quantum Money from Hidden Subspaces  

E-Print Network (OSTI)

Forty years ago, Wiesner pointed out that quantum mechanics raises the striking possibility of money that cannot be counterfeited according to the laws of physics. We propose the first quantum money scheme that is (1) public-key, meaning that anyone can verify a banknote as genuine, not only the bank that printed it, and (2) cryptographically secure, under a "classical" hardness assumption that has nothing to do with quantum money. Our scheme is based on hidden subspaces, encoded as the zero-sets of random multivariate polynomials. A main technical advance is to show that the "black-box" version of our scheme, where the polynomials are replaced by classical oracles, is unconditionally secure. Previously, such a result had only been known relative to a quantum oracle (and even there, the proof was never published). Even in Wiesner's original setting -- quantum money that can only be verified by the bank -- we are able to use our techniques to patch a major security hole in Wiesner's scheme. We give the first p...

Aaronson, Scott

2012-01-01T23:59:59.000Z

385

The research program of Stochastic Deformation (with a view toward Geometric Mechanics)  

E-Print Network (OSTI)

This is an overview of a program of stochastic deformation of the mathematical tools of classical mechanics, in the Lagrangian and Hamiltonian approaches. It can also be regarded as a stochastic version of Geometric Mechanics.The main idea is to construct well defined probability measures strongly inspired by Feynman Path integral method in Quantum Mechanics. In contrast with other approaches, this deformation preserves the invariance under time reversal of the underlying classical (conservative) dynamical systems.

Jean-Claude Zambrini

2012-12-17T23:59:59.000Z

386

Does Quantum Mechanics Clash with the Equivalence Principle - and Does it Matter?  

E-Print Network (OSTI)

With an eye on developing a quantum theory of gravity, many physicists have recently searched for quantum challenges to the equivalence principle of general relativity. However, as historians and philosophers of science are well aware, the principle of equivalence is not so clear. When clarified, we think quantum tests of the equivalence principle won't yield much. The problem is that the clash/not-clash is either already evident or guaranteed not to exist. Nonetheless, this work does help teach us what it means for a theory to be geometric.

Okon, Elias

2010-01-01T23:59:59.000Z

387

'Photosynthetic' Quantum Computers?  

E-Print Network (OSTI)

Do quantum computers already exist in Nature? It is proposed that they do. Photosynthesis is one example in which a 'quantum computer' component may play a role in the 'classical' world of complex biological systems. A 'translation' of the standard metabolic description of the 'front-end' light harvesting complex in photosynthesis into the language of quantum computers is presented. Biological systems represent an untapped resource for thinking about the design and operation of hybrid quantum-classical computers and expanding our current conceptions of what defines a 'quantum computer' in Nature.

Scott M. Hitchcock

2001-08-20T23:59:59.000Z

388

Brain-Computer Interfaces and Quantum Robots  

E-Print Network (OSTI)

The actual (classical) Brain-Computer Interface attempts to use brain signals to drive suitable actuators performing the actions corresponding to subject's intention. However this goal is not fully reached, and when BCI works, it does only in particular situations. The reason of this unsatisfactory result is that intention cannot be conceived simply as a set of classical input-output relationships. It is therefore necessary to resort to quantum theory, allowing the occurrence of stable coherence phenomena, in turn underlying high-level mental processes such as intentions and strategies. More precisely, within the context of a dissipative Quantum Field Theory of brain operation it is possible to introduce generalized coherent states associated, within the framework of logic, to the assertions of a quantum metalanguage. The latter controls the quantum-mechanical computing corresponding to standard mental operation. It thus become possible to conceive a Quantum Cyborg in which a human mind controls, through a quantum metalanguage, the operation of an artificial quantum computer.

Eliano Pessa; Paola zizzi

2009-09-08T23:59:59.000Z

389

Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes  

E-Print Network (OSTI)

Saturated and tunable emission colors make colloidal quantum-dot light-emitting diodes (QD-LEDs) interesting for the next generation of display and lighting technologies. However, there still remain various hurdles to the ...

Shirasaki, Yasuhiro

2013-01-01T23:59:59.000Z

390

Sandia National Laboratories: (QIST) Quantum Information S&T  

NLE Websites -- All DOE Office Websites (Extended Search)

the opportunity to efficiently solve problems that are numerically challenging for classical computers. Quantum computers, therefore, may someday augment conventional classical...

391

Quantum Locality?  

Science Conference Proceedings (OSTI)

Robert Griffiths has recently addressed, within the framework of a ‘consistent quantum theory’ (CQT) that he has developed, the issue of whether, as is often claimed, quantum mechanics entails a need for faster-than-light transfers of information over long distances. He argues, on the basis of his examination of certain arguments that claim to demonstrate the existence of such nonlocal influences, that such influences do not exist. However, his examination was restricted mainly to hidden-variable-based arguments that include in their premises some essentially classical-physics-type assumptions that are fundamentally incompatible with the precepts of quantum physics. One cannot logically prove properties of a system by attributing to the system properties alien to that system. Hence Griffiths’ rejection of hidden-variable-based proofs is logically warranted. Griffiths mentions the existence of a certain alternative proof that does not involve hidden variables, and that uses only macroscopically described observable properties. He notes that he had examined in his book proofs of this general kind, and concluded that they provide no evidence for nonlocal influences. But he did not examine the particular proof that he cites. An examination of that particular proof by the method specified by his ‘consistent quantum theory’ shows that the cited proof is valid within that restrictive framework. This necessary existence, within the ‘consistent’ framework, of long range essentially instantaneous influences refutes the claim made by Griffiths that his ‘consistent’ framework is superior to the orthodox quantum theory of von Neumann because it does not entail instantaneous influences. An added section responds to Griffiths’ reply, which cites a litany of ambiguities that seem to restrict, devastatingly, the scope of his CQT formalism, apparently to buttress his claim that my use of that formalism to validate the nonlocality theorem is flawed. But the vagaries that he cites do not upset the proof in question. It is show here in detail why the precise statement of this theorem justifies the specified application of CQT. It is also shown, in response to his challenge, why a putative proof of locality that he has proposed is not valid.

Stapp, Henry

2011-11-10T23:59:59.000Z

392

The Fragility of Quantum Information?  

E-Print Network (OSTI)

We address the question whether there is a fundamental reason why quantum information is more fragile than classical information. We show that some answers can be found by considering the existence of quantum memories and their dimensional dependence.

Barbara M. Terhal

2013-05-17T23:59:59.000Z

393

Local purity distillation with bounded classical communication  

E-Print Network (OSTI)

Local pure states are an important resource for quantum computing. The problem of distilling local pure states from mixed ones can be cast in an information theoretic paradigm. The bipartite version of this problem where local purity must be distilled from an arbitrary quantum state shared between two parties, Alice and Bob, is closely related to the problem of separating quantum and classical correlations in the state and in particular, to a measure of classical correlations called the one-way distillable common randomness. In Phys. Rev. A 71, 062303 (2005), the optimal rate of local purity distillation is derived when many copies of a bipartite quantum state are shared between Alice and Bob, and the parties are allowed unlimited use of a unidirectional dephasing channel. In the present paper, we extend this result to the setting in which the use of the channel is bounded. We demonstrate that in the case of a classical-quantum system, the expression for the local purity distilled is efficiently computable and provide examples with their tradeoff curves.

Hari Krovi; Igor Devetak

2007-05-28T23:59:59.000Z

394

Highly-efficient noise-assisted energy transport in classical oscillator systems  

E-Print Network (OSTI)

Photosynthesis is a biological process that involves the highly-efficient transport of energy captured from the sun to a reaction center, where conversion into useful biochemical energy takes place. Even though one can always use a quantum perspective to describe any physical process, since everything follows the laws of Quantum Mechanics, is the use of quantum theory imperative to explain this high efficiency? Making use of the quantum-classical correspondence of electronic energy transfer recently introduced by Eisfeld and Briggs [Phys. Rev. E 85, 046118 (2012)], we show here that the highly-efficient noise-assisted energy transport described by Rebentrost et al. [New J. Phys. 11, 033003 (2009)], and Plenio and Huelga [New J. Phys. 10, 113019 (2008)], as the result of the interplay between the quantum coherent evolution of the photosynthetic system and noise introduced by its surrounding environment, it can be found as well in purely classical systems. The wider scope of applicability of the enhancement of energy transfer assisted by noise might open new ways for developing new technologies aimed at enhancing the efficiency of a myriad of energy transfer systems, from information channels in micro-electronic circuits to long-distance high-voltage electrical lines.

R. de J. León-Montiel; Juan P. Torres

2013-01-08T23:59:59.000Z

395

Dark Energy from Quantum Uncertainty of Simultaneity  

E-Print Network (OSTI)

The observed acceleration expansion of the universe was thought attribute to a mysterious dark energy in the framework of the classical general relativity. The dark energy behaves very similar with a vacuum energy in quantum mechanics. However, once the quantum effects are seriously taken into account, it predicts a wrong order of the vacuum energy and leads to a severe fine-tuning, known as the cosmological constant problem. We abandon the standard interpretation that time is a global parameter in quantum mechanics, replace it by a quantum dynamical variable playing the role of an operational quantum clock system. In the framework of reinterpretation of time, we find that the synchronization of two quantum clocks distance apart can not be realized in all rigor at quantum level. Thus leading to an intrinsic quantum uncertainty of simultaneity between spatial interval, which implies a visional vacuum energy fluctuation and gives an observed dark energy density $\\rho_{de}=\\frac{6}{\\pi}L_{P}^{-2}L_{H}^{-2}$, whe...

Luo, M J

2014-01-01T23:59:59.000Z

396

Quantum Copy-Protection and Quantum Money  

E-Print Network (OSTI)

Forty years ago, Wiesner proposed using quantum states to create money that is physically impossible to counterfeit, something that cannot be done in the classical world. However, Wiesner's scheme required a central bank ...

Aaronson, Scott

397

Multimode strong-coupling quantum optomechanics  

E-Print Network (OSTI)

We study theoretically the dynamics of multiple mechanical oscillators coupled to a single cavity field mode via linear or quadratic optomechanical interactions. We focus specifically on the strong coupling regime where the cavity decays much faster than the mechanical modes, and the optomechanical coupling is comparable to or larger than the mechanical frequency, so that both the optical and mechanical systems operate in the deep quantum regime. Using the examples of one and two mechanical oscillators we show that the system can classically exhibit bistability and bifurcations, and we explore how these manifest themselves in interference, entanglement, and correlation in the quantum theory, while revealing the impact of decoherence of the mechanical system due to cavity fluctuations and coherent driving.

H. Seok; L. F. Buchmann; E. M. Wright; P. Meystre

2013-09-27T23:59:59.000Z

398

Quantum phase transitions in Bose-Fermi systems  

SciTech Connect

Research Highlights: > We study quantum phase transitions in a system of N bosons and a single-j fermion. > Classical order parameters and correlation diagrams of quantum levels are determined. > The odd fermion strongly influences the location and nature of the phase transition. > Experimental evidence for the U(5)-SU(3) transition in odd-even nuclei is presented. - Abstract: Quantum phase transitions in a system of N bosons with angular momentum L = 0, 2 (s, d) and a single fermion with angular momentum j are investigated both classically and quantum mechanically. It is shown that the presence of the odd fermion strongly influences the location and nature of the phase transition, especially the critical value of the control parameter at which the phase transition occurs. Experimental evidence for the U(5)-SU(3) (spherical to axially-deformed) transition in odd-even nuclei is presented.

Petrellis, D., E-mail: dimitris.petrellis@yale.edu [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States); Leviatan, A., E-mail: ami@phys.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Iachello, F., E-mail: francesco.iachello@yale.edu [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States)

2011-04-15T23:59:59.000Z

399

QUANTUM SUBGROUPS OF THE COMPACT QUANTUM GROUP SU-1(3) JULIEN BICHON AND ROBERT YUNCKEN  

E-Print Network (OSTI)

QUANTUM SUBGROUPS OF THE COMPACT QUANTUM GROUP SU-1(3) JULIEN BICHON AND ROBERT YUNCKEN Abstract. We study the (compact) quantum subgroups of the compact quantum group SU-1(3): we show that any non-classical such quantum subgroup is a twist of a compact subgroup of SU(3) or is isomorphic to a quantum subgroup of U-1

400

QUANTUM SUBGROUPS OF THE COMPACT QUANTUM GROUP SU-1(3) JULIEN BICHON AND ROBERT YUNCKEN  

E-Print Network (OSTI)

QUANTUM SUBGROUPS OF THE COMPACT QUANTUM GROUP SU-1(3) JULIEN BICHON AND ROBERT YUNCKEN Abstract. We study the (compact) quantum subgroups of the compact quantum group SU-1(3): we show that any such non-classical quantum subgroup is a twist of a compact subgroup of SU(3) or is isomorphic to a quantum

Sart, Remi

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Continuous Emission of A Radiation Quantum  

E-Print Network (OSTI)

It is in accordance with such experiments as single photon self-interference that a photon, conveying one radiation energy quantum "$ h \\times$ frequency", is spatially extensive and stretches an electromagnetic wave train. A wave train, hence an energy quantum, can only be emitted by its source gradually. In both the two processes the wave and "particle" attributes of the radiation field are simultaneously prominent, where an overall satisfactory theory has been lacking. This paper presents a first principles treatment, in a unified framework of the classical and quantum mechanics, of the latter process, the emission of a single radiation quantum based on the dynamics of the radiation-emitting source, a charged oscillator which is itself extensive across its confining potential well. During the emission of one single radiation quantum, the extensive charged oscillator undergoes a continuous radiation damping and is non-stationary. This process is in this work treated using a quasi stationary approach, whereby the classical equation of motion, which directly facilitates the correspondence principle for a particle oscillator, and the quantum wave equation are established for each sufficiently brief time interval. As an inevitable consequence of the division of the total time for emitting one single quantum, a fractional Planck constant $h$ is introduced. The solutions to the two simultaneous equations yield for the charged oscillator a continuously exponentially decaying Hamiltonian that is at the same time quantised with respect to the fractional-$h$ at any instant of time; and the radiation wave field emitted over time stretches a wave train of finite length. The total system of the source and radiation field maintains at any time (integer $n$ times) one whole energy quantum, $h \\times$ frequency, in complete accordance with the notion of quantum mechanics and experiment.

J. X. Zheng-Johansson

2013-11-29T23:59:59.000Z

402

Quantum Mechanical Calculations of Charge Effects on gating the KcsA channel  

DOE Green Energy (OSTI)

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. A series of ab initio (density functional) calculations were carried out on side chains of a set of amino acids, plus water, from the (intracellular) gating region of the KcsA K+ channel. Their atomic coordinates, except hydrogen, are known from X-ray structures [D.A. Doyle, J.M. Cabral, R.A. Pfuetzner, A. Kuo, J.M. Gulbis, S.L. Cohen, B.T. Chait, R. MacKinnon, The structure of the potassium channel: molecular basis of K+ conduction and selectivity, Science 280 (1998) 69–77; R. MacKinnon, S.L. Cohen, A. Kuo, A. Lee, B.T. Chait, Structural conservation in prokaryotic and eukaryotic potassium channels, Science 280 (1998) 106–109; Y. Jiang, A. Lee, J. Chen, M. Cadene, B.T. Chait, R. MacKinnon, The open pore conformation of potassium channels. Nature 417 (2001) 523–526], as are the coordinates of some water oxygen atoms. The 1k4c structure is used for the starting coordinates. Quantum mechanical optimization, in spite of the starting configuration, places the atoms in positions much closer to the 1j95, more tightly closed, configuration. This state shows four water molecules forming a “basket” under the Q119 side chains, blocking the channel. When a hydrated K+ approaches this “basket”, the optimized system shows a strong set of hydrogen bonds with the K+ at defined positions, preventing further approach of the K+ to the basket. This optimized structure with hydrated K+ added shows an ice-like 12 molecule nanocrystal of water. If the water molecules exchange, unless they do it as a group, the channel will remain blocked. The “basket” itself appears to be very stable, although it is possible that the K+ with its hydrating water molecules may be more mobile, capable of withdrawing from the gate. It is also not surprising that water essentially freezes, or forms a kind of glue, in a nanometer space; this agrees with experimental results on a rather different, but similarly sized (nm dimensions) system [K.B. Jinesh, J.W.M. Frenken, Capillary condensation in atomic scale friction: how water acts like a glue, Phys. Rev. Lett. 96 (2006) 166103/1–4].

Kariev, Alisher M.; Znamenskiy, Vasiliy S.; Green, Michael E.

2007-02-06T23:59:59.000Z

403

Unconditional conversion between quantum particles and waves  

E-Print Network (OSTI)

Wave-particle duality is a basic notion of quantum mechanics, which has largely contributed to many debates on the foundations of quantum theory. Besides this fundamental aspect of the wave-particle nature of quantum systems, recently, it turned out that, in order to construct more advanced and efficient protocols in quantum communication and information processing, it is also beneficial to combine continuous-wave and discrete-particle features in a so-called hybrid fashion. However, in traditional, quantum optical complementarity tests, monitoring the light waves would still happen in an effectively particle-like fashion, detecting the fields click by click. Similarly, close-to-classical, wave-like coherent states, as readily available from standard laser sources, or other Gaussian states generated through nonlinear optical interactions, have been so far experimentally converted into non-classical quantum superpositions of distinct waves only in a conditional fashion. Here we experimentally demonstrate the deterministic conversion of a single-photon state into a quantum superposition of two weak coherent states with opposite phases - a Schrodinger kitten state - and back. Conceptually different from all previous experiments, as being fully reversible, this can be interpreted as a quantum gate, connecting the complementary regimes of particle-like and wave-like light fields in a unitary fashion, like in a quantum computation. Such an unconditional conversion is achieved by means of a squeezing operation, demonstrating a fundamental feature of any quantum system: particle-like and wave-like properties can be reversibly altered, with no need for filtering out either through detection.

Yoshichika Miwa; Jun-ichi Yoshikawa; Noriaki Iwata; Mamoru Endo; Petr Marek; Radim Filip; Peter van Loock; Akira Furusawa

2012-09-13T23:59:59.000Z

404

Quantum Operations and Measurement  

E-Print Network (OSTI)

Quantum Operations and Measurement M.P Seevinck E-mail: M.P.Seevinck@phys.uu.nl Utrecht field in quantum physics ­ or perhaps better, a new way of doing quantum physics ­ . . . Surprisingly of these developments to the conceptual problems of quantum mechanics. In our view, the new work on quantum information

Seevinck, Michiel

405

Quantum Operations and Measurement  

E-Print Network (OSTI)

Quantum Operations and Measurement # M.P Seevinck # E­mail: M.P.Seevinck@phys.uu.nl Utrecht in quantum physics -- or perhaps better, a new way of doing quantum physics -- . . . Surprisingly, with few to the conceptual problems of quantum mechanics. In our view, the new work on quantum information changes

Seevinck, Michiel

406

Collective motion in quantum diffusive environment  

E-Print Network (OSTI)

The general problem of dissipation in macroscopic large-amplitude collective motion and its relation to energy diffusion of intrinsic degrees of freedom of a nucleus is studied. By applying the cranking approach to the nuclear many-body system, a set of coupled dynamical equations for the collective classical variable and the quantum mechanical occupancies of the intrinsic nuclear states is derived. Different dynamical regimes of the intrinsic nuclear motion and its consequences on time properties of collective dissipation are discussed.

V. M. Kolomietz; S. Å berg; S. V. Radionov

2007-06-16T23:59:59.000Z

407

Types of quantum information  

E-Print Network (OSTI)

Quantum, in contrast to classical, information theory, allows for different incompatible types (or species) of information which cannot be combined with each other. Distinguishing these incompatible types is useful in understanding the role of the two classical bits in teleportation (or one bit in one-bit teleportation), for discussing decoherence in information-theoretic terms, and for giving a proper definition, in quantum terms, of ``classical information.'' Various examples (some updating earlier work) are given of theorems which relate different incompatible kinds of information, and thus have no counterparts in classical information theory.

Robert B. Griffiths

2007-07-25T23:59:59.000Z

408

Quantum mechanics of layers with a finite number of point perturbations  

Science Conference Proceedings (OSTI)

We study spectral and scatteringproperties of a spinless quantum particle confined to an infinite planar layer with hard walls containing a finite number of point perturbations. A solvable character of the model follows from the explicit form of the Hamiltonian resolvent obtained by means of Krein’s formula. We prove the existence of bound states

P. Exner; K. N?mcová

2002-01-01T23:59:59.000Z

409

Arbitrarily little knowledge can give a quantum advantage for nonlocal tasks  

E-Print Network (OSTI)

It has previously been shown that quantum nonlocality offers no benefit over classical correlations for performing a distributed task known as nonlocal computation. This is where separated parties must compute the value of a function without individually learning anything about the inputs. We show that giving the parties some knowledge of the inputs, however small, is sufficient to unlock the power of quantum mechanics to out-perform classical mechanics. This role of information held locally gives new insight into the general question of when quantum nonlocality gives an advantage over classical physics. Our results also reveal a novel feature of the nonlocality embodied in the celebrated task of Clauser, Horne, Shimony and Holt.

Jonathan Allcock; Harry Buhrman; Noah Linden

2009-03-03T23:59:59.000Z

410

Classical QGP : IV. Thermodynamics  

E-Print Network (OSTI)

We construct the equation of a state of the classical QGP valid for all values of Gamma=V/K, the ratio of the mean Coulomb to kinetic energy. By enforcing the Gibbs relations, we derive the pertinent pressure and entropy densities for all Gamma. For the case of an SU(2) classical gluonic plasma our results compare well with lattice simulations. We show that the strongly coupled component of the classical QGP contributes significantly to the bulk thermodynamics across T_c.

Sungtae Cho; Ismail Zahed

2008-12-09T23:59:59.000Z

411

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile  

SciTech Connect

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

412

Channel simulation with quantum side information  

E-Print Network (OSTI)

We study and solve the problem of classical channel simulation with quantum side information at the receiver. This is a generalization of both the classical reverse Shannon theorem, and the classical-quantum Slepian-Wolf problem. The optimal noiseless communication rate is found to be reduced from the mutual information between the channel input and output by the Holevo information between the channel output and the quantum side information. Our main theorem has two important corollaries. The first is a quantum generalization of the Wyner-Ziv problem: rate-distortion theory with quantum side information. The second is an alternative proof of the trade-off between classical communication and common randomness distilled from a quantum state. The fully quantum generalization of the problem considered is quantum state redistribution. Here the sender and receiver share a mixed quantum state and the sender wants to transfer part of her state to the receiver using entanglement and quantum communication. We present o...

Luo, Z; Devetak, Igor; Luo, Zhicheng

2006-01-01T23:59:59.000Z

413

Why Do the Quantum Observables Form a Jordan Operator Algebra?  

E-Print Network (OSTI)

The Jordan algebra structure of the bounded real quantum observables was recognized already in the early days of quantum mechanics. While there are plausible reasons for most parts of this structure, the existence of the distributive nonassociative multiplication operation is hard to justify from a physical or statistical point of view. Considering the non-Boolean extension of classical probabilities, presented in a recent paper, it is shown in this paper that such a multiplication operation can be derived from certain properties of the conditional probabilities and the observables, i.e., from postulates with a clear statistical interpretation. The well-known close relation between Jordan operator algebras and C*-algebras then provides the connection to the quantum-mechanical Hilbert space formalism, thus resulting in a novel axiomatic approach to general quantum mechanics that includes the types II and III von Neumann algebras.

Gerd Niestegge

2010-01-21T23:59:59.000Z

414

Time and Entropy in the Foundations of Mechanics  

E-Print Network (OSTI)

This contribution analyses the classical laws of motion by means of an approach relating time and entropy. We argue that adopting the notion of change of states as opposed to the usual derivation of Newton's laws in terms of fields a broader picture is obtained, suggesting that diverse branches of physics- classical, quantum, relativistic and statistical mechanics - turn out to be related by a common foundation.

R Assumpcao

2007-06-17T23:59:59.000Z

415

Quantum optical waveform conversion  

E-Print Network (OSTI)

Currently proposed architectures for long-distance quantum communication rely on networks of quantum processors connected by optical communications channels [1,2]. The key resource for such networks is the entanglement of matter-based quantum systems with quantum optical fields for information transmission. The optical interaction bandwidth of these material systems is a tiny fraction of that available for optical communication, and the temporal shape of the quantum optical output pulse is often poorly suited for long-distance transmission. Here we demonstrate that nonlinear mixing of a quantum light pulse with a spectrally tailored classical field can compress the quantum pulse by more than a factor of 100 and flexibly reshape its temporal waveform, while preserving all quantum properties, including entanglement. Waveform conversion can be used with heralded arrays of quantum light emitters to enable quantum communication at the full data rate of optical telecommunications.

Kielpinski, D; Wiseman, HM

2010-01-01T23:59:59.000Z

416

Manipulation of Non-classical Atomic Spin States  

E-Print Network (OSTI)

We report successful manipulation of non-classical atomic spin states. We generate squeezed spin states by a spin quantum nondemolition measurement, and apply an off-resonant circularly-polarized light pulse to the atoms. By changing the pulse duration, we have clearly observed a rotation of anisotropic quantum noise distribution in good contrast with the case of manipulation of a coherent spin state where the quantum noise distribution is always isotropic. This is an important step for quantum state tomography, quantum swapping, and precision spectroscopic measurement.

Tetsushi Takano; Shin-Ichi-Ro Tanaka; Ryo Namiki; Yoshiro Takahashi

2009-09-13T23:59:59.000Z

417

Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality  

E-Print Network (OSTI)

Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical, and that do not have a simple description in terms of weakly interacting quasi-particles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by more than 20 orders of magnitude in temperature, but they were shown to exhibit very similar hydrodynamic flow. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and it also serves as an introduction to the Focus Issue of New Journal of Physics on Strongly Correlated Quantum Fluids: from Ultracold Quantum Gases to QCD Plasmas. The presentation is made accessible to the general physics reader and includes discussions of the latest research developments in all three areas.

Allan Adams; Lincoln D. Carr; Thomas Schaefer; Peter Steinberg; John E. Thomas

2012-05-23T23:59:59.000Z

418

Protein/Ligand Binding Free Energies Calculated with Quantum Mechanics/Molecular Frauke Gra1ter,, Sonja M. Schwarzl,, Annick Dejaegere,| Stefan Fischer,*, and  

E-Print Network (OSTI)

Protein/Ligand Binding Free Energies Calculated with Quantum Mechanics/Molecular Mechanics Frauke of the complexes are predicted (the "docking" problem) as well as in how the free energy is calculated from)solvation during the binding process.3 Typically, binding free energies calculated with these methods have average

Gräter, Frauke

419

NIST 'Quantum Tuning Forks' Demonstrate Directly Coupling ...  

Science Conference Proceedings (OSTI)

... for quantum simulations, which may help explain the mechanisms of complex quantum systems such as high-temperature superconductors. ...

2011-03-02T23:59:59.000Z

420

A bird's eye view of quantum computers  

E-Print Network (OSTI)

Quantum computers are discussed in the general framework of computation, the laws of physics and the foundations of quantum mechanics.

Giuliano Benenti; Giuliano Strini

2007-03-13T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Quantum and Post Quantum Cryptography Abderrahmane Nitaj  

E-Print Network (OSTI)

Quantum and Post Quantum Cryptography Abderrahmane Nitaj Laboratoire de Math´ematiques Nicolas based on quantum mechanics for factoring large integers and computing discrete loga- rithms undermined Gamal and ECC. However, some cryptosystems, called post quantum cryptosystems, while not currently

Nitaj, Abderrahmane

422

Quantum Mechanical Energy-based Screening of Combinatorially Generated Library of Tautomers. TauTGen: A Tautomer Generator Program  

Science Conference Proceedings (OSTI)

Many computational methods have been derived from quantum mechanics for molecular and extended systems. We advocate that these methods will soon become indispensable research tools of combinatorial chemistry. Although applications of these combinatorial methods driven by quantum-mechanics-derived computational engines seem to be distant, our recent experience suggests the opposite. We developed algorithms and codes to search for the most stable tautomers of molecules. In our approach, we: (i) create large libraries of molecular tautomers using combinatorial methods, and (ii) prescreen these libraries using quantum chemical electronic structure methods. We have identified many adiabatically bound and previously unknown tautomers of anionic nucleic acid bases. Our results unraveled that ordering of nucleic acid bases according to their affinity to an excess electron is: G > U > T > C > A , when all biologically relevant tautomers are considered. Acknowledgements This work was supported by the: (i) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.) and (ii) Polish State Committee for Scientific Research (KBN) Grant DS/8221-4-0140-4 (M.H.). M.H. thanks for financial support from the European Union Social Funds ZPORR/2.22/II/2.6/ARP/U/2/O5. M.H. is a holder of the award from the Fundation for Polish Science (FNP). R.A.B. acknowledges the financial support from Nanoquant EC Marie Curie Research Training Network, contract number: MRTN-506842. Computing resources were available through: (i) the Academic Computer Center in Gda?sk (TASK) (ii) a Computational Grand Challenge Application grant from the Molecular Sciences Computing Facility (MSCF) in the Environmental Molecular Sciences Laboratory located at the Pacific Northwest National Laboratory, and (iii) the National Energy Research Scientific Computing Center (NERSC). The MSCF is funded by DOE’s Office of Biological and Environmental Research. PNNL is operated by Battelle for the U.S. DOE under Contract DE-AC06-76RLO 1830.

Haranczyk, Maciej; Gutowski, Maciej S.

2007-03-01T23:59:59.000Z

423

A Simple Quantum-Mechanical Model of Spacetime II: Thermodynamics of Spacetime  

E-Print Network (OSTI)

In this second part of our series of two papers, where spacetime is modelled by a graph, where Planck size quantum black holes lie on the vertices, we consider the thermodynamics of spacetime. We formulate an equation which tells in which way an accelerating, spacelike two-surface of spacetime interacts with the thermal radiation flowing through that surface. In the low temperature limit, where most quantum black holes constituting spacetime are assumed to lie in the ground state, our equation implies, among other things, the Hawking and the Unruh effects, as well as Einstein's field equation with a vanishing cosmological constant for general matter fields. We also consider the high temperature limit, where the microscopic black holes are assumed to lie in highly excited states. In this limit our model implies, among other things, that black hole entropy depends logarithmically on its area, instead of being proportional to the area.

J. Makela

2008-05-26T23:59:59.000Z

424

Mechanism of terahertz photoconductivity in semimetallic HgTe/CdHgTe quantum wells  

Science Conference Proceedings (OSTI)

Terahertz photoconductivity in magnetic fields in semimetallic HgTe/CdHgTe quantum wells has been studied. The main contribution to photoconductivity comes from a signal that appears as a result of electron-gas heating. It is shown that, with the cyclotron resonance conditions satisfied, the photoconductivity signal is composed of cyclotron-resonance and bolometric components. However, in this case too, the bolometric contribution predominates.

Vasilyev, Yu. B., E-mail: yu.vasilyev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Mikhailov, N. N. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gouider, F. [Institut fuer Angewandte Physik (Germany); Vasilyeva, G. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Nachtwei, G. [Institut fuer Angewandte Physik (Germany)

2012-05-15T23:59:59.000Z

425

Symmetry, Self-Duality and the Jordan Structure of Quantum Mechanics  

E-Print Network (OSTI)

I explore several related routes to deriving the Jordan-algebraic structure of finite-dimensional quantum theory from more transparent operational or physical principles, mainly involving ideas about the symmetries of, and the correlations between, probabilistic models. The key tool is the Koecher-Vinberg Theorem, which identifies formally real Jordan algebras with finite-dimensional order-unit spaces having homogeneous, self-dual cones.

Alexander Wilce

2011-10-30T23:59:59.000Z

426

Quantum Discord for Investigating Quantum Correlations without Entanglement in Solids  

E-Print Network (OSTI)

Quantum systems unfold diversified correlations which have no classical counterparts. These quantum correlations have various different facets. Quantum entanglement, as the most well known measure of quantum correlations, plays essential roles in quantum information processing. However, it has recently been pointed out that quantum entanglement cannot describe all the nonclassicality in the correlations. Thus the study of quantum correlations in separable states attracts widely attentions. Herein, we experimentally investigate the quantum correlations of separable thermal states in terms of quantum discord. The sudden change of quantum discord is observed, which captures ambiguously the critical point associated with the behavior of Hamiltonian. Our results display the potential applications of quantum correlations in studying the fundamental properties of quantum system, such as quantum criticality of non-zero temperature.

Rong, Xing; Jin, Fangzhou; Geng, Jianpei; Feng, Pengbo; Xu, Nanyang; Wang, Ya; Ju, Chenyong; Shi, Mingjun; Du, Jiangfeng

2012-01-01T23:59:59.000Z

427

Information content of financial markets: a practical approach based on Bohmian quantum mechanics  

E-Print Network (OSTI)

The Bohmian quantum approach is implemented to analyze the financial markets. In this approach, there is a wave function that leads to a quantum potential. This potential can explain the relevance and entanglements of the agent's behaviors with the past. The light is shed by considering the relevance of the market conditions with the previous market conditions enabling the conversion of the local concepts to the global ones. We have shown that there are two potential limits for each market. In essence, these potential limits act as a boundary which limits the return values inside it. By estimating the difference between these two limits in each market, it is found that the quantum potentials of the return time series in different time scales, possess a scaling behavior. The slopes of the scaling behaviors in mature, emerging and commodity markets show different patterns. The emerge market having a slope greater than 0.5, has a higher value compared to the corresponding values for the mature and commodity mark...

Tahmasebi, F; Namaki, A; Jafari, G R

2012-01-01T23:59:59.000Z

428

Experimental verification of quantum computations  

E-Print Network (OSTI)

Quantum computers are expected to offer substantial speedups over their classical counterparts and to solve problems that are intractable for classical computers. Beyond such practical significance, the concept of quantum computation opens up new fundamental questions, among them the issue whether or not quantum computations can be certified by entities that are inherently unable to compute the results themselves. Here we present the first experimental verification of quantum computations. We show, in theory and in experiment, how a verifier with minimal quantum resources can test a significantly more powerful quantum computer. The new verification protocol introduced in this work utilizes the framework of blind quantum computing and is independent of the experimental quantum-computation platform used. In our scheme, the verifier is only required to generate single qubits and transmit them to the quantum computer. We experimentally demonstrate this protocol using four photonic qubits and show how the verifier can test the computer's ability to perform measurement-based quantum computations.

Stefanie Barz; Joseph F. Fitzsimons; Elham Kashefi; Philip Walther

2013-08-30T23:59:59.000Z

429

Quantum secret sharing with qudit graph states  

Science Conference Proceedings (OSTI)

We present a unified formalism for threshold quantum secret sharing using graph states of systems with prime dimension. We construct protocols for three varieties of secret sharing: with classical and quantum secrets shared between parties over both classical and quantum channels.

Keet, Adrian; Fortescue, Ben; Sanders, Barry C. [Institute for Quantum Information Science, University of Calgary, Alberta, T2N 1N4 (Canada); Markham, Damian [LTCI-CNRS, Telecom ParisTech, 37/39 rue Dareau, F-75014 Paris (France)

2010-12-15T23:59:59.000Z

430

Quantum secret sharing with qudit graph states  

E-Print Network (OSTI)

We present a unified formalism for threshold quantum secret sharing using graph states of systems with prime dimension. We construct protocols for three varieties of secret sharing: with classical and quantum secrets shared between parties over both classical and quantum channels.

Adrian Keet; Ben Fortescue; Damian Markham; Barry C. Sanders

2010-04-26T23:59:59.000Z

431

General model of quantum key distribution  

E-Print Network (OSTI)

A general mathematical framework for quantum key distribution based on the concepts of quantum channel and Turing machine is suggested. The security for its special case is proved. The assumption is that the adversary can perform only individual (in essence, classical) attacks. For this case an advantage of quantum key distribution over classical one is shown.

A. S. Trushechkin; I. V. Volovich

2005-04-20T23:59:59.000Z

432

A comparative study of iterative solutions to linear systems arising in quantum mechanics  

Science Conference Proceedings (OSTI)

This study is mainly focused on iterative solutions with simple diagonal preconditioning to two complex-valued nonsymmetric systems of linear equations arising from a computational chemistry model problem proposed by Sherry Li of NERSC. Numerical experiments show the feasibility of iterative methods to some extent when applied to the problems and reveal the competitiveness of our recently proposed Lanczos biconjugate A-orthonormalization methods to other classic and popular iterative methods. By the way, experiment results also indicate that application specific preconditioners may be mandatory and required for accelerating convergence.

Jing Yanfei, E-mail: yanfeijing@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Huang Tingzhu, E-mail: tzhuang@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Duan Yong, E-mail: duanyong@yahoo.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Carpentieri, Bruno, E-mail: b.carpentieri@rug.n [Institute of Mathematics and Computing Science, University of Groningen, Nijenborgh 9, P.O. Box 407, 9700 AK Groningen (Netherlands)

2010-11-01T23:59:59.000Z

433

Hydrogen Beyond the Classic Approximation  

E-Print Network (OSTI)

The classical nucleus approximation is the most frequently used approach for the resolution of problems in condensed matter physics.However, there are systems in nature where it is necessary to introduce the nuclear degrees of freedom to obtain a correct description of the properties.Examples of this, are the systems with containing hydrogen.In this work, we have studied the resolution of the quantum nuclear problem for the particular case of the water molecule.The Hartree approximation has been used, i.e. we have considered that the nuclei are distinguishable particles.In addition, we have proposed a model to solve the tunneling process, which involves the resolution of the nuclear problem for configurations of the system away from its equilibrium position

Scivetti, I

2003-01-01T23:59:59.000Z

434

Quantum bit string sealing  

E-Print Network (OSTI)

Though it was proven that secure quantum sealing of a single classical bit is impossible in principle, here we propose an unconditionally secure quantum sealing protocol which seals a classical bit string. Any reader can obtain each bit of the sealed string with an arbitrarily small error rate, while reading the string is detectable. The protocol is simple and easy to be implemented. The possibility of using this protocol to seal a single bit in practical is also discussed.

Guang-Ping He

2005-02-15T23:59:59.000Z

435

Reducing the quantum communication cost of quantum secret sharing  

E-Print Network (OSTI)

We demonstrate a construction for perfect quantum secret sharing (QSS) schemes based on imperfect "ramp" secret sharing combined with classical encryption, in which the individual parties' shares are split into quantum and classical components, allowing the former to be of lower dimension than the secret itself. We show that such schemes can be performed with smaller quantum components and lower overall quantum communication than required for existing methods. Finally, we demonstrate that one may further combine both imperfect quantum and imperfect classical secret sharing to produce an overall perfect QSS scheme; we construct examples of such schemes and prove that they have the smallest quantum and classical share components possible for their access structures.

Fortescue, Ben

2011-01-01T23:59:59.000Z

436

Reducing the quantum communication cost of quantum secret sharing  

E-Print Network (OSTI)

We demonstrate a new construction for perfect quantum secret sharing (QSS) schemes based on imperfect "ramp" secret sharing combined with classical encryption, in which the individual parties' shares are split into quantum and classical components, allowing the former to be of lower dimension than the secret itself. We show that such schemes can be performed with smaller quantum components and lower overall quantum communication than required for existing methods. We further demonstrate that one may combine both imperfect quantum and imperfect classical secret sharing to produce an overall perfect QSS scheme, and that examples of such scheme (which we construct) can have the smallest quantum and classical share components possible for their access structures, something provably not achievable using perfect underlying schemes. Our construction has significant potential for being adapted to other QSS schemes based on stabiliser codes.

Ben Fortescue; Gilad Gour

2011-08-29T23:59:59.000Z

437

Google in a Quantum Network  

E-Print Network (OSTI)

We introduce the characterization of a class of quantum PageRank algorithms in a scenario in which some kind of quantum network is realizable out of the current classical internet web, but no quantum computer is yet available. This class represents a quantization of the PageRank protocol currently employed to list web pages according to their importance. We have found an instance of this class of quantum protocols that outperforms its classical counterpart and may break the classical hierarchy of web pages depending on the topology of the web.

G. D. Paparo; M. A. Martin-Delgado

2011-12-09T23:59:59.000Z

438

Classically spinning and isospinning solitons  

SciTech Connect

We investigate classically spinning topological solitons in (2+1)- and (3+1)-dimensional models; more explicitely spinning sigma model solitons in 2+1 dimensions and Skyrme solitons in 2+1 and 3+1 dimensions. For example, such types of solitons can be used to describe quasiparticle excitations in ferromagnetic quantum Hall systems or to model spin and isospin states of nuclei. The standard way to obtain solitons with quantised spin and isospin is the semiclassical quantization procedure: One parametrizes the zero-mode space - the space of energy-degenerate soliton configurations generated from a single soliton by spatial translations and rotations in space and isospace - by collective coordinates which are then taken to be time-dependent. This gives rise to additional dynamical terms in the Hamiltonian which can then be quantized following semiclassical quantization rules. A simplification which is often made in the literature is to apply a simple adiabatic approximation to the (iso)rotational zero modes of the soliton by assuming that the soliton's shape is rotational frequency independent. Our numerical results on classically spinning arbitrarily deforming soliton solutions clearly show that soliton deformation cannot be ignored.

Battye, Richard A.; Haberichter, Mareike [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-09-26T23:59:59.000Z

439

Bohmian Mechanics  

E-Print Network (OSTI)

Bohmian mechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmian mechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmian mechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.

Detlef Duerr; Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

2009-03-15T23:59:59.000Z

440

The quantum Euler class and the quantum cohomology of the Grassmannians  

E-Print Network (OSTI)

The quantum Euler class and the quantum cohomology of the Grassmannians Lowell Abrams December 4 to quantum cohomology endows these rings with the structure of a Frobenius algebra. Any such algebra, and in the quantum case this is a deformation of the classical Euler class which we call the ``quantum Euler class

Abrams, Lowell

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Time-dependent simulations of large-scale quantum mechanical processes  

SciTech Connect

Time dependent linear and nonlinear equations govern the evolution of an extensive set of physical systems and processes describing, to enumerate just a few, Bose-Einstein condensates; soliton propagation in optical and photonic band-gap fibers; quantum control of atomic and molecular collisions and reactions; highly-compressed liquids; and dense and ultracold plasmas. While the media vary substantially, the basic computational procedures have many common features. We focus on the nonlinear Schrodinger equation and discuss two powerful approaches to its propagation: the Arnoldi/Lanczos(AL)l and Real Space Product Formula(RSPF)2. Both provide efficient systematic approximations to the short-time exponential propagator that moves the solution between time steps. We implement the former in a discrete variable representation (DVR)3 both in spatial grid and finite element forms and the latter in a spatial mesh with a finite difference representation of the kinetic energy operator. Both approaches require O(N) operations to propagate the wavefunction between time steps and handle multidimensional systems. We shall also draw connections with Liouville formulations used in quantum molecular dynamics simulations of large collections of atoms and molecules. After briefly outlining these formulations, we shall discuss some of the varied applications.

Collins, L. A. (Lee A.)

2002-01-01T23:59:59.000Z

442

Homodyne detection and optical parametric amplification: a classical approach applied to proposed "loophole-free" Bell tests  

E-Print Network (OSTI)

Recent proposed ``loophole-free'' Bell tests are discussed in the light of classical models for the relevant features of optical parametric amplification and homodyne detection. The Bell tests themselves are uncontroversial: there are no obvious loopholes that might cause bias and hence, if the world does, after all, obey local realism, no violation of a Bell inequality will be observed. Interest centres around the question of whether or not the proposed criterion for ``non-classical'' light is valid. If it is not, then the experiments will fail in their initial concept, since both quantum theorists and local realists will agree that we are seeing a purely classical effect. The Bell test, though, is not the only criterion by which the quantum-mechanical and local realist models can be judged. It is suggested that the quantum-mechanical models given in the proposals will also fail in their detailed predictions. If the experiments are extended by including a range of parameter values and by analysing, in addition to the proposed digitised voltage differences, the raw voltages, the models can be compared in their overall performance and plausibility.

Caroline H Thompson

2005-12-17T23:59:59.000Z

443

Modified gravity from the quantum part of the metric  

E-Print Network (OSTI)

It is shown that if a metric in quantum gravity can be decomposed as a sum of classical and quantum parts then Einstein quantum gravity looks approximately like modified gravity with a nonminimal interaction between gravity and matter.

Vladimir Dzhunushaliev; Vladimir Folomeev; Burkhard Kleihaus; Jutta Kunz

2013-12-01T23:59:59.000Z

444

Zero-error capacity of a quantum channel  

E-Print Network (OSTI)

We define the quantum zero-error capacity, a new kind of classical capacity of a noisy quantum channel. Moreover, the necessary requirement for which a quantum channel has zero-error capacity greater than zero is also given.

Rex A. C. Medeiros; Francisco M. de Assis

2004-03-26T23:59:59.000Z

445

From Quantum Cheating to Quantum Security  

E-Print Network (OSTI)

For thousands of years, code-makers and code-breakers have been competing for supremacy. Their arsenals may soon include a powerful new weapon: quantum mechanics. We give an overview of quantum cryptology as of November 2000.

Daniel Gottesman; Hoi-Kwong Lo

2001-11-19T23:59:59.000Z

446

Guest column: the quantum PCP conjecture  

Science Conference Proceedings (OSTI)

The classical PCP theorem is arguably the most important achievement of classical complexity theory in the past quarter century. In recent years, researchers in quantum computational complexity have tried to identify approaches and develop tools that ...

Dorit Aharonov; Itai Arad; Thomas Vidick

2013-06-01T23:59:59.000Z

447

New mechanism for nonlocality from string theory: UV-IR quantum entanglement and its imprints on the CMB  

Science Conference Proceedings (OSTI)

Puff field theories (PFT) arise as the decoupling limits of D3 branes in a Melvin universe and exhibit spatially nonlocal dynamics. Unlike other realizations of nonlocality in string theory, PFTs have full SO(3) rotational symmetry. In this work, we analyze the strongly coupled regime of a PFT through gravitational holography. We find a novel mechanism at the heart of the phenomenon of nonlocality: a quantum entanglement of UV and IR dynamics. In the holographic bulk, this translates to an apparent horizon splitting the space into two regions--with the UV completion of the PFT sitting at the horizon. We unravel this intricate UV-IR setting and devise a prescription for computing correlators that extends the original dictionary of holographic renormalization group. We then implement a cosmological scenario where PFT correlators set the initial conditions for primordial fluctuations. We compute the associated power spectrum of the cosmic microwave background and find that the scenario allows for a distinct stringy signature.

Minton, Gregory; Sahakian, Vatche [Harvey Mudd College, Physics Department, 241 Platt Boulevard, Claremont, California 91711 (United States)

2008-01-15T23:59:59.000Z

448

Quantum information cannot be completely hidden in correlations: implications for the black-hole information paradox  

E-Print Network (OSTI)

The black-hole information paradox has fueled a fascinating effort to reconcile the predictions of general relativity and those of quantum mechanics. Gravitational considerations teach us that black holes must trap everything that falls into them. Quantum mechanically the mass of a black hole leaks away as featureless (Hawking) radiation, but if the black hole vanishes, where is the information about the matter that made it? We treat the states of the in-fallen matter quantum mechanically and show that the black-hole information paradox becomes more severe. Our formulation of the paradox rules out one of the most conservative resolutions: that the state of the in-falling matter might be hidden in correlations between semi-classical Hawking radiation and the internal states of the black hole. As a consequence, either unitarity or Hawking's semi-classical predictions must break down. Any resolution of the black-hole information crisis must elucidate one of these possibilities.

Samuel L. Braunstein; Arun K. Pati

2006-03-13T23:59:59.000Z

449

Ultraviolet Complete Quantum Gravity  

E-Print Network (OSTI)

An ultraviolet complete (UV) quantum gravity theory is formulated in which vertex functions in Feynman graphs are entire functions and the propagating gravitons are described by local, causal propagators. A scalar-tensor action describes classical gravity theory. The cosmological constant problem is investigated in the context of the UV complete quantum gravity.

Moffat, J W

2010-01-01T23:59:59.000Z

450

Two-electron reduction of ethylene carbonate: a quantum chemistry re-examination of mechanisms  

E-Print Network (OSTI)

Passivating solid-electrolyte interphase (SEI) films arising from electrolyte decomposition on low-voltage lithium ion battery anode surfaces are critical for battery operations. We review the recent theoretical literature on electrolyte decomposition and emphasize the modeling work on two-electron reduction of ethylene carbonate (EC, a key battery organic solvent). One of the two-electron pathways, which releases CO gas, is re-examined using simple quantum chemistry calculations. Excess electrons are shown to preferentially attack EC in the order (broken EC^-) > (intact EC^-) > EC. This confirms the viability of two electron processes and emphasizes that they need to be considered when interpreting SEI experiments. An estimate of the crossover between one- and two-electron regimes under a homogeneous reaction zone approximation is proposed.

Leung, Kevin

2013-01-01T23:59:59.000Z

451

Quantum Geometry in the Lab  

E-Print Network (OSTI)

Standard particle theory is based on quantized matter embedded in a classical geometry. Here, a complementary model is proposed, based on classical matter -- massive bodies, without quantum properties -- embedded in a quantum geometry. It does not describe elementary particles, but may be a better, fully consistent quantum description for position states in laboratory-scale systems. Gravitational theory suggests that the geometrical quantum system has an information density of about one qubit per Planck length squared. If so, the model here predicts that the quantum uncertainty of geometry creates a new form of noise in the position of massive bodies, detectable by interferometers.

Craig Hogan

2013-03-24T23:59:59.000Z

452

Quantum Ice : a quantum Monte Carlo study  

E-Print Network (OSTI)

Ice states, in which frustrated interactions lead to a macroscopic ground-state degeneracy, occur in water ice, in problems of frustrated charge order on the pyrochlore lattice, and in the family of rare-earth magnets collectively known as spin ice. Of particular interest at the moment are "quantum spin ice" materials, where large quantum fluctuations may permit tunnelling between a macroscopic number of different classical ground states. Here we use zero-temperature quantum Monte Carlo simulations to show how such tunnelling can lift the degeneracy of a spin or charge ice, stabilising a unique "quantum ice" ground state --- a quantum liquid with excitations described by the Maxwell action of 3+1-dimensional quantum electrodynamics. We further identify a competing ordered "squiggle" state, and show how both squiggle and quantum ice states might be distinguished in neutron scattering experiments on a spin ice material.

Nic Shannon; Olga Sikora; Frank Pollmann; Karlo Penc; Peter Fulde

2011-05-20T23:59:59.000Z

453

Quantum Operation Time Reversal  

E-Print Network (OSTI)

The dynamics of an open quantum system can be described by a quantum operation, a linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes towards equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

Crooks, Gavin E

2007-01-01T23:59:59.000Z

454

Quantum Operation Time Reversal  

E-Print Network (OSTI)

The dynamics of an open quantum system can be described by a quantum operation, a linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes towards equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

Gavin E. Crooks

2007-06-26T23:59:59.000Z

455

Quantum Physics and Nanotechnology  

E-Print Network (OSTI)

Experimental studies of infinite (unrestricted at least in one direction) quantum particle motion using probe nanotechnologies have revealed the necessity of revising previous concepts of their motion. Particularly, quantum particles transfer quantum motion nonlocality energy beside classical kinetic energy, in other words, they are in two different kinds of motion simultaneously. The quantum component of the motion energy may be quite considerable under certain circumstances. Some new effects were predicted and proved experimentally in terms of this phenomenon. A new prototype refrigerating device was tested, its principle of operation being based on the effect of transferring the quantum component of the motion energy.

Vladimir K. Nevolin

2011-06-06T23:59:59.000Z

456

Quantum deduction rules (preliminary version)  

E-Print Network (OSTI)

Quantum deduction rules (preliminary version) Pavel Pudlâ??ak # March 27, 2007 Abstract We define propositional quantum Frege proof systems and compare it with classical Frege proof systems. 1 Introduction In this paper we shall address the question whether quantum circuits could help us prove theorems faster than

Pudlák, Pavel

457

Macroscopic quantum behaviour of periodic quantum systems  

E-Print Network (OSTI)

In this paper we introduce a simple procedure for computing the macroscopic quantum behaviour of periodic quantum systems in the high energy regime. The macroscopic quantum coherence is ascribed to a one-particle state, not to a condensate of a many-particle system; and we are referring to a system of high energy but with few degrees of freedom. We show that, in the first order of approximation, the quantum probability distributions converge to its classical counterparts in a clear fashion, and that the interference effects are strongly suppressed. The harmonic oscillator provides a testing ground for these ideas and yields excellent results.

A. Martín-Ruiz; J. Bernal; Adrián Carbajal-Domínguez

2013-09-02T23:59:59.000Z

458

Quantum Statistics Madalin Guta  

E-Print Network (OSTI)

Quantum Statistics Madalin Gut¸a School of Mathematics University of Nottingham 1 #12;The old paradigm Quantum Mechanics up to the 80's Quantum measurements have random results Only probability particles, any more than we can raise Ichtyosauria in the zoo 2 #12;The new paradigm Individual quantum

Guta, Madalin

459

Direct measure of quantum correlation  

SciTech Connect

The quantumness of the correlation known as quantum correlation is usually measured by quantum discord. So far various quantum discords can be roughly understood as indirect measure by some special discrepancy of two quantities. We present a direct measure of quantum correlation by revealing the difference between the structures of classically and quantum correlated states. Our measure explicitly includes the contributions of the inseparability and local nonorthogonality of the eigenvectors of a density matrix. Besides its relatively easy computability, our measure can provide a unified understanding of quantum correlation of all the present versions.

Yu, Chang-shui [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Zhao, Haiqing [School of Science, Dalian Jiaotong University, Dalian 116028 (China)

2011-12-15T23:59:59.000Z

460

Phase Conjugation in Quantum Optomechanics  

E-Print Network (OSTI)

We analyze the phase conjugate coupling of a pair of optomechanical oscillator modes driven by the time-dependent beat-note due to a two-color optical field. The dynamics of the direct and phase conjugate modes exhibit familiar time-reversed qualities, leading to opposite sign temperatures for the modes in the classical regime of operation, but these features are limited by quantum effects due to the non-commutative nature of quantum mechanical operators. The effects are measurable by read-out of the oscillator via a qubit. As a potential application of this system in sensing, we discuss a protocol applying phase-conjugate swaps to cancel external forces acting on the system.

L. F. Buchmann; E. M. Wright; P. Meystre

2013-05-08T23:59:59.000Z

Note: This page contains sample records for the topic "quantum mechanics classical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

On Quantum Integrable Systems  

SciTech Connect

Many quantum integrable systems are obtained using an accelerator physics technique known as Ermakov (or normalized variables) transformation. This technique was used to create classical nonlinear integrable lattices for accelerators and nonlinear integrable plasma traps. Now, all classical results are carried over to a nonrelativistic quantum case. In this paper we have described an extension of the Ermakov-like transformation to the Schroedinger and Pauli equations. It is shown that these newly found transformations create a vast variety of time dependent quantum equations that can be solved in analytic functions, or, at least, can be reduced to time-independent ones.

Danilov, Viatcheslav; /Oak Ridge; Nagaitsev, Sergei; /Fermilab

2011-11-01T23:59:59.000Z

462

Classicalization via Path Integral  

E-Print Network (OSTI)

Recently, it was suggested that a large class of non-renormalizable theories may need no UV completion. By analogy with gravity where classical black holes are expected to be created in high-energy scatterings, it is conjectured that similar classical solutions, so-called classicalons, should occur. In this way the theory protects itself against non-unitarity, for instead of probing small distances at high energies one enters a classical regime. An effective theory of Goldstone bosons provides and example in which the size of classicalons grows with energy, and the high energy scattering is cut-off by small momenta, inversely proportional to the classicalon size. In this note we offer an alternative, path integral discussion of this important result.

Borut Bajc; Arshad Momen; Goran Senjanovi?

2011-02-17T23:59:59.000Z

463

Classicalization via Path Integral  

E-Print Network (OSTI)

Recently, it was suggested that a large class of non-renormalizable theories may need no UV completion. By analog