Quantum Ratchets
Abstract
The concept of thermal ratchets is extended to the systemgoverned by quantum mechanics. We study a tight-binding model withan asymmetric periodic potential contacting with a heat bath underan external oscillating field as a specific example of quantumratchet. The dynamics of a density operator of this system arestudied numerically using the quantum Liouville equation. Thefinite net current is found in the nonequilibrium steady state,which originates from purely quantum mechanical effects. Thedirection of the current varies with parameters, in contrast withthe classical thermal ratchets.
- Publication:
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Journal of the Physical Society of Japan
- Pub Date:
- October 1997
- DOI:
- 10.1143/JPSJ.66.2953
- arXiv:
- arXiv:cond-mat/9706222
- Bibcode:
- 1997JPSJ...66.2953Y
- Keywords:
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- Condensed Matter - Statistical Mechanics;
- Quantum Physics
- E-Print:
- 7 pages, Latex, 4 ps figures