A model of spontaneous generation of population inversion in open quantum systems Original Research Article

Mathematical theorems by Davies justify, upon a specific choice of the scaling parameter, the weak-coupling relaxation theory. We use this exact mathematics again but with another, equally admissible and physically motivated, scaling parameter beyond regime of the weak system–bath coupling. This allows us to study very specific particle vs. surroundings correlations of a type known from, e.g., molecular biology. A model utilizing these correlations is suggested and solved using the above rigorous mathematics here. It yields successive spontaneous excitation of a particle at positive bath temperatures to finite number of excited states, with even dominating asymptotic population of the highest one, challenging thus standard statistical thermodynamics. Model assumptions are shortly discussed but no approximate steps are involved.