2009/08/31 by C. E. Creffield, Fernando Sols, F. Sols · 1 citation
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Spectroscopy and Quantum Chemical Studies #cond-mat.quant-gas #stochastic dynamics and bifurcation
paper · pdf · doi:10.1103/physrevlett.103.200601
published as Phys. Rev. Lett. 103, 200601 (2009) · 5 pages, 4 eps figures. Minor changes, this version to be published in PRL
arxiv created 2009/11/03 · openalex publication_date 2009/11/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the response of a Bose-Einstein condensate to an unbiased periodic driving potential. By controlling the space and time symmetries of the driving we show how a directed current can be induced, producing a coherent quantum ratchet. Weak driving induces a regular behavior, and space and time symmetries must both be broken to produce a current. For strong driving, the behavior becomes chaotic and the resulting effective irreversibility means that it is unnecessary to explicitly break time symmetry. Spatial asymmetry alone is then sufficient to produce the ratchet effect, even in the absence of interactions, and although the system remains completely coherent.