Experimental demonstrations of a new second law-like theorem

Full text: The puzzle of how time-reversible microscopic equations of mechanics lead to the time-irreversible macroscopic equations of thermodynamics has existed since the days of Boltzmann. Boltzmann simply side-stepped this paradox, stating as soon as one looks at bodies of small dimension, the validity of this theorem [the Second Law of Thermodynamics] must cease.' Today we state that the Fluctuation Theorem (FT) is a generalised, Second-Law like theorem that bridges the time-reversible and irreversible descriptions. Here we describe recent experiments where 'violations' in the Second Law occur over experimentally realisable time and length scales, consistent with the predictions of the FT. Copyright (2005) Australian Institute of Physics