%0 Journal Article %@ 0031-9007 %A Jones, PH %A Goonasekera, M %A Renzoni, F %D 2004 %F discovery:9658 %I AMERICAN PHYSICAL SOC %J PHYS REV LETT %K STOCHASTIC RESONANCE, BROWNIAN MOTORS, THERMAL RATCHETS, DRIVEN SYSTEMS, RECTIFICATION, DIFFUSION, TRANSPORT, SYMMETRY, SQUIDS, ATOMS %N 7 %P ? - ? %T Rectifying fluctuations in an optical lattice %U https://discovery.ucl.ac.uk/id/eprint/9658/ %V 93 %X We have realized a Brownian motor by using cold atoms in a dissipative optical lattice as a model system. In our experiment the optical potential is spatially symmetric and the time symmetry of the system is broken by applying appropriate zero-mean ac forces. We identify a regime of rectification of forces and a regime of rectification of fluctuations, the latter corresponding to the realization of a Brownian motor.