Real-time determination of free energy and losses in optical absorbing media

摘要

We introduce notions of free energy and loss in linear, absorbing dielectricmedia which are relevant to the regime in which the macroscopic Maxwellequations are themselves relevant. As such we solve a problem eluded to byLandau and Lifshitz in 1958, and later considered explicitly by Barash andGinzburg, and Oughtsun and Sherman. As such we provide physically-relevantreal-time notions of "energy" and "loss" in all analogous linear dissipativesystems.