Schedule Aug 24, 2012
Quantum Transport of Ultra-cold Atoms in 1D Optical Lattices Studied by Micro-canonical Formalism
CHIH-CHUN CHIEN1, M. Zwolak2, M. Di Ventra3, 1Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87544, USA., 2 Department of Physics, Oregon State University, Corvallis, OR 97331, USA., 3Department of Physics, University of California, San Diego, CA 92093, USA. , ,

Ultra-cold atoms in optical lattices provide ideal and clean systems for studying quantum transport in a controllable fashion due to the tunability of the interactions among atoms, the density of atoms, temperature, lattice depth and size, and other physical quantities. Here we propose several methods for driving a quasi steady-state current (QSSC) of fermions using an external bias, density- or interaction-imbalance. The QSSC corresponds to a plateau in the mass current as a function of time and could be useful in designing novel cold-atom based devices. We simulate the quantum dynamics using a micro-canonical formalism [1] that monitors the evolution of the single-particle correlation matrix. This formalism is particularly suitable for isolated quantum systems like ultra-cold atoms in optical lattices. We found that the fermionic QSSC is a many-body phenomenon not observable when only a few atoms are present [2]. In contrast, bosons in their ground state do not support a QSSC [1]. More interestingly, in both bias-driven and interaction-induced transport we report a dynamical conducting-nonconducting transition, which may be explained by a mismatch of the energy spectra of different parts of the system [3].

[ 1] C. C. Chien, M. Zwolak, and M. Di Ventra, Phys. Rev. A 85, 041601(R) (2012).
[ 2] C. C. Chien and M. Di Ventra, arXiv:1204.4715 (2012).
[ 3] C. C. Chien, M. Di Ventra, and M. Zwolak, arXiv:1203.5094 (2012).

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