Participating group members: |
Mykhaylo Evstigneev, Peter Reimann |

Main external cooperation partners: |
Chris Van den Broeck, Ryoichi Kawai |

Coupled Brownian particles in a symmetric potential, exhibiting a spontaneous symmetry breaking and a concomitant spontaneous ratchet effect (directed transport). |

Non-equilibrium fluctuations in combination with interaction effects give rise to surprising new phenomena in complex physical and biological systems, for instance negative mobility, anomalous hysteresis loops, and spontaneous directed transport, in spatially symmetric periodic systems. In deterministically monostable systems they may induce phase-transitions, spontaneous symmetry-breaking, and spontaneous synchronized oscillations, and they may be exploited for the stabilization of deterministically unstable states.

A first experimental demonstration of these theoretical concepts
has been realized by means of
granular gases.
A further related project deals with collective,
stochastic resonance-like phenomena in colloidal systems.

Publications:

P. Reimann, R. Kawai, C. Van den Broeck, and P. Hänggi

*Coupled Brownian Motors: Anomalous Hysteresis and Zero-bias Negative Conductance*

Europhys. Lett. **45**, 545 (1999)

This work is illustrated by a
movie (1.1 MB), of which the above figure is a snapshot.

C. Van den Broeck, P. Reimann, R. Kawai, and P. Hänggi

*Coupled Brownian Motors*

pp. 93-111 in
"Statistical Mechanics and Biocomplexity",
Lecture Notes in Physics, Vol. 527

edited by D. Reguera, J.M. Rubi, and J.M.G. Vilar,
Springer, Berlin, 1999

P. Reimann, C. Van den Broeck, and R. Kawai

*Nonequilibrium Noise in Coupled Phase Oscillators*

Phys. Rev. E **60**, 6402 (1999)

C. Van den Broeck, I. Bena, P. Reimann, and J. Lehmann

*Coupled Brownian Motors on a Tilted Washboard*

Ann. Phys. (Leipzig) **9**, 713 (2000)

*Last update on August 2, 2004.*