Destructive effect of fluctuations on the performance of a Brownian gyrator.

The Brownian gyrator (BG) is often called a minimal model of a nano-engine performing a rotational motion, judging solely upon the fact that in non-equilibrium conditions its torque, specific angular momentum  and specific angular velocity  have non-zero mean values. For a (with time-step ) model we calculate here the previously unknown probability density functions (PDFs) of  and . We show that for finite , the PDF of  has exponential tails and all moments are therefore well-defined.