Nonequilibrium work distributions for a trapped Brownian particle in a time-dependent magnetic field

Abstract

We study the dynamics of a trapped, charged Brownian particle in the presence of a time-dependent magnetic field. We calculate work distributions for different time-dependent protocols numerically. In our problem, thermodynamic work is related to variation of the vector potential with time as opposed to the earlier studies where the work is related to time variation of the potentials, a quantity that depends only on the coordinates of the particle. Using the Jarzynski and the Crooks equalities, we show that the free energy of the particle is independent of the magnetic field, thus complementing the Bohr-van Leeuwen theorem. We also show that our system exhibits a parametric resonance in a certain parameter space. © 2008 The American Physical Society.