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Quantum Dynamics (quantum + dynamics)
Selected AbstractsQuantum dynamics of a discontinuously kicked charged particle in harmonic, symmetric double, or triple wellsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2009S. Ghosh Abstract The quantum dynamics of a charged particle in a harmonic trap in the presence of discontinuous reversals of a homogeneous or an inhomogeneous electric field is studied. The dynamics reveals classically expected patterns in harmonic wells. In a symmetric double-well potential, the discontinuously switched low intensity homogeneous electric field does not appear to assist tunneling, whereas an inhomogeneous electric field is found to assist the process. Resonance like enhancement is noticed at a critical reversal frequency. Dynamics in a triple well is also analyzed under similar conditions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Quantum dynamics with trajectories.INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 7 2006Introduction to quantum hydrodynamics No abstract is available for this article. [source] Short-range ±J interaction Ising spin glass in a transverse field on a Bethe lattice: a quantum-spherical approachPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2006T. K. Kope Abstract We consider the short-range interaction disordered quantum Ising model with symmetric binary ±J bond distribution on the Bethe lattice (with coordination number z). The system exhibits quantum phase transition separating the spin glass and disordered phases where the quantum effect are regulated by a param- eter , describing the transverse field. By introducing a mapping of the quantum Hamiltonian of the model onto a soft-spin action we consider it truncated version in a form of the solvable quantized spherical model. Quantum dynamics is examined via various correlation functions on the infinite tree which are evaluated in a closed form. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Gauge-independent quantum dynamics on phase-space of charged scalar particlesFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 2-3 2003S. Varró On the basis of the Hamiltonian form of the Klein-Gordon equation of a charged scalar particle field introduced by Feshbach and Villars, the gauge-invariant 2×2 Wigner matrix has been constructed whose diagonal elements describe positive and negative charge densities and the off-diagonal elements correspond to cross-densities in phase-space. The system of coupled transport equations has been derived in case of interaction with an arbitrary external electromagnetic field. A gauge-independent generalization of the free particle representation due to Feshbach and Villars is given, and on the basis of it both the nonrelativistic and the classical limits of the general relativistic quantum Boltzmann-Vlasov equation(RQBVE) is discussed. In the non-relativistic limit (p/mc,0) the set of equations of motion decouple to two independent quantum transport equations describing the dynamics of oppositely charged positon and negaton densities separately. In the classical limit(,,0) two relativistic Boltzmann-Vlasov equations result for the diagonal positon and negaton densities. It is obtained that, though in the latter equations the Planck constant , is absent, the real part of the cross-density does not vanish. [source] Parallelization of the quantum dynamics code for cluster architecture and its applications to the Gross,Pitaevskii equationINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2006Adam Gorecki Abstract We present a parallel version of a quantum dynamics (QD) algorithm in a wave function representation. The algorithm has been optimized for a Linux cluster as well as for Cray T3E, using a parallel version of a three-dimensional FFT library. We have applied this algorithm for solving the nonlinear Gross,Pitaevskii equation (GPE), which describes the evolution of Bose,Einstein condensates (BEC) in the mean field approximation. Our method reduces the computational time and allows the study of nonlinear quantum systems. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] Theoretical study on quantum dynamics of bose system interacting with photon fieldINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2001Hidemi Nagao Abstract We investigate the quantum dynamics of two-boson and two-level systems interacting with a one-mode photon field. The time evolution of the population for each state is calculated in terms of the Jaynes,Cummings model. We find the collapses and revivals of the order parameter for the Bose,Einstein condensation. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 401,408, 2001 [source] The Role of Charge Localization in Current-Driven DynamicsISRAEL JOURNAL OF CHEMISTRY, Issue 1 2007Ryan Jorn We explore the role of charge localization in current-triggered, resonance-mediated, dynamical events in molecular junctions. To that end we use a simple model for a molecular rattle, a Li+C9H,9 zwitterion attached between two metal clusters. By varying the size of the metal clusters we systematically vary the degree of delocalization of the electronic orbitals underlying the resonant current, and thus can draw general conclusions regarding the effect of delocalization on dynamical processes induced by resonance inelastic current in molecular electronics. In the small cluster limit, we find interesting quantum dynamics in the nuclear subspace, corresponding to coherent tunneling of the wave packet through the barrier of an asymmetric double-well potential. These dynamics are rapidly damped with increasing charge delocalization in extended systems. [source] Computational studies of nonadiabatic effects in gas,surface encountersISRAEL JOURNAL OF CHEMISTRY, Issue 1-2 2005Cécile Corriol Model studies are presented, each of which employs a different approach to solving the problem of nonadiabatic dynamics occurring at a solid surface. The jumping wave packet-type approach involving dynamics on two potential energy surfaces punctuated by Franck,Condon transitions was applied to the dynamics of CO desorbed from Ru following energetic electron bombardment. Classical dynamics was also employed in this system to gain a more detailed understanding of the factors important to the final molecular state distribution. To study charge transfer from an alkali-halide surface to a scattering atom, we have used full multi-surface quantum dynamics. A simple, but effective, analysis method was used to make a more detailed connection between the potential energy surfaces and the dynamics. To study the fate of the transferred electron and to model how this depends on substrate and projectile species, we have used a four-dimensional wave packet implementation in which two of the dimensions explicitly account for the electron dynamics. Finally, we consider the famous electron,hole pair excitation problem, from a density functional theory perspective. Spin nonadiabaticity is found to be a new important feature in gas,metal surface interactions. [source] | |||||||||||||