Underdamped quantum ratchetsS. Denisov, S. Kohler and P. Hänggi
Institut für Physik, Universität Augsburg - Universitätsstraße 1, D-86135 Augsburg, Germany, EU
received 14 November 2008; accepted in final form 21 January 2009; published February 2009
published online 18 February 2009
We investigate the quantum ratchet effect under the influence of weak dissipation which we treat within a Floquet-Markov master equation approach. A ratchet current emerges when all relevant symmetries are violated. Using time-reversal symmetric driving we predict a purely dissipation-induced quantum ratchet current. This directed quantum transport results from bath-induced superpositions of non-transporting Floquet states.
05.60.Gg - Quantum transport.
37.10.Jk - Atoms in optical lattices.
05.45.Mt - Quantum chaos; semiclassical methods.
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