Comment on ``Reexamination of experimental tests of the fluctuation theorem" by Narayan and Dhar

Abstract

Our result in cond-mat/0305147 that, instead of the conventional heat fluctuation theorem (FT), a new FT holds for heat fluctuations for a Brownian particle in a moving confining potential[Wang et al. 2002], was claimed to be disproved in a very recent preprint by Narayan and Dhar, cond-mat/0307148. This comment is meant to show that their assertion is not correct. The point is that they formulate their FT differently than we do ours. Effectively, their FT speaks about a physically irrelevant limiting case of our new FT. This implies that the two \FT s are not in contradiction with each other. Furthermore, we point out an incorrect assumption in their derivation.