skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Dissipationless directed transport in rocked single-band quantum dynamics

Abstract

Using matter waves that are trapped in a deep optical lattice, dissipationless directed transport is demonstrated to occur if the single-band quantum dynamics is periodically tilted on one half of the lattice by a monochromatic field. Most importantly, the directed transport can exist for almost all system parameters, even after averaged over a broad range of single-band initial states. The directed transport is theoretically explained within ac-scattering theory. Total reflection phenomena associated with the matter waves traveling from a tilting-free region to a tilted region are emphasized. The results are of relevance to ultracold physics and solid-state physics, and may lead to powerful means of selective, coherent, and directed transport of cold particles in optical lattices.

Authors:
;  [1];  [2];  [3]
  1. Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117542 (Singapore)
  2. Theoretische Physik I, Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany)
  3. (Singapore)
Publication Date:
OSTI Identifier:
20982371
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.033602; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; MONOCHROMATIC RADIATION; OPTICAL MODELS; PERIODICITY; QUANTUM MECHANICS; REFLECTION; SCATTERING; SOLID STATE PHYSICS; TEMPERATURE RANGE 0000-0013 K; TRAPPING

Citation Formats

Gong, Jiangbin, Poletti, Dario, Hanggi, Peter, and Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117542. Dissipationless directed transport in rocked single-band quantum dynamics. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.033602.
Gong, Jiangbin, Poletti, Dario, Hanggi, Peter, & Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117542. Dissipationless directed transport in rocked single-band quantum dynamics. United States. doi:10.1103/PHYSREVA.75.033602.
Gong, Jiangbin, Poletti, Dario, Hanggi, Peter, and Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117542. Thu . "Dissipationless directed transport in rocked single-band quantum dynamics". United States. doi:10.1103/PHYSREVA.75.033602.
@article{osti_20982371,
title = {Dissipationless directed transport in rocked single-band quantum dynamics},
author = {Gong, Jiangbin and Poletti, Dario and Hanggi, Peter and Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117542},
abstractNote = {Using matter waves that are trapped in a deep optical lattice, dissipationless directed transport is demonstrated to occur if the single-band quantum dynamics is periodically tilted on one half of the lattice by a monochromatic field. Most importantly, the directed transport can exist for almost all system parameters, even after averaged over a broad range of single-band initial states. The directed transport is theoretically explained within ac-scattering theory. Total reflection phenomena associated with the matter waves traveling from a tilting-free region to a tilted region are emphasized. The results are of relevance to ultracold physics and solid-state physics, and may lead to powerful means of selective, coherent, and directed transport of cold particles in optical lattices.},
doi = {10.1103/PHYSREVA.75.033602},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • The observable characteristics and phase-space structure of systems formed by dissipationless collapse are investigated. An extensive set of N-body simulations is described; and three-dimensional and spherical collapses, their shapes, and dynamics are examined. It is demonstrated that collapses started from cold initial conditions are quantitatively different from warm collapses, in the sense that their final shapes are nearly uncorrelated with their initial shapes. It is suggested that this phenomenon is due to an instability similar to the radial-orbit instability in anisotropic equilibrium models. The results show that clumpy initial conditions are not required to produce a realistic final state viamore » collapse, if the initial state is sufficiently cold; and that if elliptical galaxies collapsed from cold and smooth initial configurations (and did not evolve significantly thereafter), they should be triaxial or prolate, with intrinsic flattening of approximately 2:1. 24 refs.« less
  • An approach to spin dynamics in systems with many degrees of freedom, based on a recognition of the constraints common to all large systems, is developed and used to study the excitation of multiple-quantum coherence under a nonsecular dipolar Hamiltonian. The exact equation of motion is replaced by a set of coupled rate equations whose exponential solutions reflect the severe damping expected when many closely spaced frequency components are superposed. In this model the evolution of multiple-quantum coherence under any bilinear Hamiltonian is treated as a succession of discrete hops in Liouville space, with each hop taking the system frommore » a K-spin/n-quantum mode to a K'-spin/n'-quantum mode. In particular, for a pure double-quantum Hamiltonian the selection rules are ..delta..K = +- 1 and ..delta..n = +- 2. The rate for each move depends on the number of Liouville states at the origin and destination, and on the total number of spins present. All rates are scaled uniformly by a factor dependent on the properties of the material, such as the dipolar linewidth, but otherwise the behavior predicted is universal for all sufficiently complicated systems. Results derived by this generic approach are compared to existing multiple-quantum data obtained from solids and liquid crystals.« less
  • We report on the first demonstration of chaos-assisted directed transport of a quantum particle held in an amplitude-modulated and tilted optical lattice, through a resonance-induced double-mean displacement relating to the true classically chaotic orbits. The transport velocity is controlled by the driving amplitude and the sign of tilt, and also depends on the phase of the initial state. The chaos-assisted transport feature can be verified experimentally by using a source of single atoms to detect the double-mean displacement one by one, and can be extended to different scientific fields.
  • We introduce a tight-binding approach to model the emission dynamics of a quantum-dot in realistic, photonic-crystal-slab coupled-cavity systems. We apply our approach to a quantum-dot strongly coupled at the band edge of a lossy coupled-cavity waveguide and calculate the quantum-dot dynamics as well as the photon dynamics along the waveguide. We show that the condition for strong coupling is simply parametrized in terms of the waveguide loss and find that the key signature of the strong-coupling, Rabi oscillations, could be observed via time-resolved photon detection.
  • Quantum transport in disordered systems is studied using a polaron-based master equation. The polaron approach is capable of bridging the results from the coherent band-like transport regime governed by the Redfield equation to incoherent hopping transport in the classical regime. A non-monotonic dependence of the diffusion coefficient is observed both as a function of temperature and system-phonon coupling strength. In the band-like transport regime, the diffusion coefficient is shown to be linearly proportional to the system-phonon coupling strength and vanishes at zero coupling due to Anderson localization. In the opposite classical hopping regime, we correctly recover the dynamics described bymore » the Fermi’s Golden Rule and establish that the scaling of the diffusion coefficient depends on the phonon bath relaxation time. In both the hopping and band-like transport regimes, it is demonstrated that at low temperature, the zero-point fluctuations of the bath lead to non-zero transport rates and hence a finite diffusion constant. Application to rubrene and other organic semiconductor materials shows a good agreement with experimental mobility data.« less