> Isn't this a lossless process of the sort forbidden by thermodynamics? It is lossless on the single-particle level, but not in large thermodynamic ensembles

> Isn't this a lossless process of the sort forbidden by thermodynamics? It is lossless on the single-particle level, but not in large thermodynamic ensembles of many, many particles. There, only most photons interact losslessly, while some get absorbed nonetheless, heat up the glass and give you thermodynamics. How exactly unitary quantum mechanical time evolution transforms into ergodic, classical and thermodynamic time evolution in large systems is (relatively) open question.