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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,315 records · Page 73
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DOE OSTI2011

Dynamics, Spectral Geometry and Topology

The paper is an informal report on joint work with Stefan Haller on Dynamics in relation with Topology and Spectral Geometry. By dynamics one means a smooth vector field on a closed smooth manifold; the elements of dynamics of concern are the rest points, instantons and closed trajectories. One discusses their counting in the case of a generic vector field which has some additional properties satisfied by a still very large class of vector fields.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

AKNS hierarchy, Darboux transformation and conservation laws of the 1D nonautonomous nonlinear Schroedinger equations

By constructing nonisospectral Ablowitz-Kaup-Newell-Segur (AKNS) hierarchy, we investigate the nonautonomous nonlinear Schroedinger (NLS) equations which have been used to describe the Feshbach resonance management in matter-wave solitons in Bose-Einstein condensate and the dispersion and nonlinearity managements for optical solitons. It is found that these equations are some special cases of a new integrable model of nonlocal nonautonomous NLS equations. Based on the Lax pairs, the Darboux transformation and conservation laws are explored. It is shown that the local external potentials would break down the classical infinite number of conservation laws. The result indicates that the integrability of the nonautonomous NLS systems may be nontrivial in comparison to the conventional concept of integrability in the canonical case.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2011

Reduced Probabilities of E2-Transitions in {sup 174}Yb

This paper describes the ground (gr) and exited states of even-even deformed nuclei with a phenomenological model, which takes into account the mixing of gr states, 0{sub n}{sup +}({beta}{sub n})-, 2{sub n}{sup +}({gamma}{sub n})- and {Kappa}{sup {pi}} 1{sub n}{sup +}- rotational bands. The calculation has been done for the isotope Yb. The energy spectra are found to be consistent with the energies from experimental data. The reduced probabilities of the electric quadrupole E2-transitions from {beta}{sub n} and {gamma}{sub n} band states are calculated and agree quite well with the experimental values.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Dynamic symmetries and entropic inequalities in the probability representation of quantum mechanics

The probability representation of quantum and classical statistical mechanics is discussed. Symplectic tomography, center-of-mass tomography, and spin tomography are studied. The connection of tomographic probabilities with dynamic symmetries like symplectic group is considered. Entropic uncertainty relations and inequalities for spin tomograms are reviewed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Transient effects in quantum decay

These lecture notes review exact analytical results for quantum transients concerning the time evolution of decay for potentials of finite range by using the formalism of resonant states.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

On the approach to thermal equilibrium of macroscopic quantum systems

In joint work with J. L. Lebowitz, C. Mastrodonato, and N. Zanghi[2, 3, 4], we considered an isolated, macroscopic quantum system. Let H be a micro-canonical 'energy shell', i.e., a subspace of the system's Hilbert space spanned by the (finitely) many energy eigenstates with energies between E and E+{delta}E. The thermal equilibrium macro-state at energy E corresponds to a subspace H{sub eq} of H such that dimHeq/dimH is close to 1. We say that a system with state vector {psi}{epsilon}H is in thermal equilibrium if {psi} is 'close' to H{sub eq}. We argue that for 'typical' Hamiltonians, all initial state vectors {psi}{sub 0} evolve in such a way that {psi}{sub t} is in thermal equilibrium for most times t. This is closely related to von Neumann's quantum ergodic theorem of 1929.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Large deviations of the current in a two-dimensional diffusive system

In this notes we study the large deviations of the time-averaged current in the two-dimensional (2D) Kipnis-Marchioro-Presutti model of energy transport when subject to a boundary gradient. We use the tools of hydrodynamic fluctuation theory, supplemented with an appropriate generalization of the additivity principle. As compared to its one-dimensional counterpart, which amounts to assume that the optimal profiles responsible of a given current fluctuation are time-independent, the 2D additivity conjecture requires an extra assumption, i.e. that the optimal, divergence-free current vector field associated to a given fluctuation of the time-averaged current is in fact constant across the system. Within this context we show that the current distribution exhibits in general non-Gaussian tails. The ensuing optimal density profile can be either monotone for small current fluctuations, or non-monotone with a single maximum for large enough current deviations. Furthermore, this optimal profile remains invariant under arbitrary rotations of the current vector, providing a detailed example of the recently introduced Isometric Fluctuation Relation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Stochastic resonance between propagating extended attractors

The nonequilibrium Ising--Bloch (NIB) bifurcation of the FitzHugh-Nagumo (FHN) model with nondiffusing inhibitor provides a beautiful instance of an extended bistable system with counterpropagating fronts or Bloch walls (BW) as stable attractors. Moreover, these fronts are chiral and parity-related, and the barrier between them is the unstable stationary front or Ising wall (IW). Here we show by means of numerical simulation the presence of stochastic resonance in the transition between 1D BW of opposite chiralities when an additive noise is included. A scaling law of the signal-to-noise ratio (SNR) with the distance to the critical point is numerically observed and theoretically characterized in terms of an effective nonequilibrium potential.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

A non-equilibrium potential function to study competition in neural systems

In this work, I overview some novel results concerning the theoretical calculation of a non-equilibrium potential function for a biologically motivated model of a neural network. Such model displays competition between different populations of excitatory and inhibitory neurons, which is known to originate synchronous dynamics, fast activity oscillations, and other nontrivial behavior in more sophisticated models of neural media.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Long-range interacting systems and dynamical phase transitions

We briefly review the derivation of the Vlasov equation, which is a convenient approximation for the description of the transport properties of long-range interacting systems. We then point out that the presence of an external source of noise, like for instance a heat bath, induces dynamical phase transitions from ordered non-equilibrium Vlasov-stable states to disordered ones.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Duality Quantum Information and Duality Quantum Communication

Quantum mechanical systems exhibit particle wave duality property. This duality property has been exploited for information processing. A duality quantum computer is a quantum computer on the move and passing through a multi-slits. It offers quantum wave divider and quantum wave combiner operations in addition to those allowed in an ordinary quantum computer. It has been shown that all linear bounded operators can be realized in a duality quantum computer, and a duality quantum computer with n qubits and d-slits can be realized in an ordinary quantum computer with n qubits and a qudit in the so-called duality quantum computing mode. The quantum particle-wave duality can be used in providing secure communication. In this paper, we will review duality quantum computing and duality quantum key distribution.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Micro-Macro Duality and Space-Time Emergence

The microscopic origin of space-time geometry is explained on the basis of an emergence process associated with the condensation of infinite number of microscopic quanta responsible for symmetry breakdown, which implements the basic essence of 'Quantum-Classical Correspondence' and of the forcing method in physical and mathematical contexts, respectively. From this viewpoint, the space-time dependence of physical quantities arises from the 'logical extension' to change 'constant objects' into 'variable objects' by tagging the order parameters associated with the condensation onto ''constant objects''; the logical direction here from a value y to a domain variable x(to materialize the basic mechanism behind the Gel'fand isomorphism) is just opposite to that common in the usual definition of a function f : x->f(x) from its domain variable x to a value y = f(x).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Dynamical quantum non-locality

Quantum Mechanics allows one to independently fix both the initial and final state of a single system. Novel effects occur for such systems, challenging our ideas about what time is and how it flows.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Dual Schroedinger Equation as Global Optimization Algorithm

The dual Schroedinger equation is defined as replacing the imaginary number i by -1 in the original one. This paper shows that the dual equation shares the same stationary states as the original one. Different from the original one, it explicitly defines a dynamic process for a system to evolve from any state to lower energy states and eventually to the lowest one. Its power as a global optimization algorithm might be used by nature for constructing atoms and molecules. It shall be interesting to verify its existence in nature.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Temporal coherence length of light in semiclassical field theory models

The following work is motivated by the conceptual problems associated with the wave-particle duality and the notion of the photon. Two simple classical models for radiation from individual emitters are compared, one based on sines with random phasejumps, another based on pulse trains. The sum signal is calculated for a varying number of emitters. The focus lies on the final signal's statistical features quantified by means of the temporal coherence function and the temporal coherence length. We show how these features might be used to experimentally differentiate between the models. We also point to ambiguities in the definition of the temporal coherence length.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Quantum Decay of the 'False Vacuum' and Pair Creation of Soliton Domain Walls

Quantum decay of metastable states ('false vacua') has been proposed as a mechanism for bubble nucleation of new universes and phase transitions in the early universe. Experiments indicate the occurrence of false vacuum decay, within a region bounded by soliton domain walls that nucleate via quantum tunneling, in a highly anisotropic condensed matter system. This phenomenon provides a compelling example of false vacuum decay in the laboratory.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Quantum Theory Event-Probability Interpretation

In this article the propagation of pointlike event probabilities in space is considered. New interpretation of Quantum Theory is formulated.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Weak Value Theory

I show that the weak value theory is useful from the viewpoints of the experimentally verifiability, consistency, capacity for explanation as to many quantum paradoxes, and practical advantages. As an example, the initial state in the Hardy paradox can be experimentally verified using the weak value via the weak measurement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗