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TU Dresden » Faculty of Mechanical Science and Engineering » Institute for Materials Science » Chair of Materials Science and Nanotechnology



Monday, 12 July 2004
(at 16:15 in room H34)
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Quantum ratchets

Milena Grifoni

Institut für Theoretische Physik
Universität Regensburg
   






Ratchets are periodic structures lacking spatial inversion symmetry. Despite the asymmetry, no preferential motion occurs for particles moving in a ratchet potential and being only subject to equilibrium thermal noise, in agreement with the second law of thermodynamics. However, directed motion can occur under the combined effect of thermal noise and unbiased driving forces.
We investigate this so-called ratchet effect for Brownian particles moving in one-dimensional ratchet structures. We focus on temperatures such that tunnelling is the dominant transport mechanism. We discuss the occurrence of current reversals as the parameters of the bath or of the driving force are varied.
We finally report on the recent experimental observation of the quantum ratchet effect for vortices in quasi one-dimensional arrays of Josephson junctions.

phys. dept. links: abstract(pdf file)



slides (pdf)

Within the Physikalisches Kolloquium SS04

last modified: 2018.10.24 Mi
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