Prof Vlatko Vedral FInstP

Abstract:

We derive a general informationtheoretic equality for a system undergoing two projective measurements separated by a general temporal evolution. The equality implies the non-negativity of the mutual information between the measurement outcomes of the earlier and later projective measurements. We show that it also contains the Jarzynski relation between the average exponential of the thermodynamical work and the exponential of the difference between the initial and final free energy. Our result elucidates the informationtheoretic underpinning of thermodynamics and explains why the Jarzynski relation holds identically both quantumly as well as classically. © 2012 IOP Publishing Ltd.

Abstract:

In this paper I discuss the question: what comes first, physics or information? The two have had a long-standing, symbiotic relationship for almost a hundred years out of which we have learnt a great deal. Information theory has enriched our interpretations of quantum physics, and, at the same time, offered us deep insights into general relativity through the study of black hole thermodynamics. Whatever the outcome of this debate, I argue that physicists will be able to benefit from continuing to explore connections between the two. © 2012 by the authors; licensee MDPI, Basel, Switzerland.