  We study a Brownian motor, based on cold atoms in optical lattices, where
atomic motion can be induced in a controlled manner in an arbitrary direction,
by rectification of isotropic random fluctuations. In contrast with ratchet
mechanisms, our Brownian motor operates in a potential that is spatially and
temporally symmetric, in apparent contradiction to the Curie principle.
Simulations, based on the Fokker-Planck equation, allow us to gain knowledge on
the qualitative behaviour of our Brownian motor. Studies of Brownian motors,
and in particular ones with unique control properties, are of fundamental
interest because of the role they play in protein motors and their potential
applications in nanotechnology. In particular, our system opens the way to the
study of quantum Brownian motors.
