Classification of quantum coherences for thermalization of a single-mode cavity

Ceren B. Dağ, Özgür E. Müstecaplıoğlu

Published 2015-07-29Version 1

While quantum coherence is usually a goal to achieve, transfer, and maintain in quantum systems out of chaos, it has recently become a center of attention as a resource for thermalization. There are many coherences in a given many body quantum system. Our purpose is to distinguish coherences which can contribute to pure thermalization. For that aim, we consider a three atom quantum thermalizing machine for a single mode cavity. Deriving the master equation and solving it in the steady state for a general initial state of the atoms, we examine the interplay of coherence and detailed balance for thermalization of the cavity field. We find that the atomic coherences can be classified into disjoint sets with purely thermal and coherent contributions. Possibility to turn the atoms into pure, coherent, or squeezed thermal reservoirs is shown. As applications of the general formalism, the symmetric W state is shown to be the most optimum thermalizing state among all W-class states, whereas GHZ state is not suitable for thermalization, which is another fundamental difference between the two distinct classes of three atom entangled states emerging in the realm of quantum thermodynamics. Furthremore, we propose a mixture of W states that can utilize all the allowed coherences for pure thermalization to ultrahigh temperatures.