Thermalization and dephasing in collisional reservoirs

TL;DR

This paper studies quantum maps in collisional reservoirs, showing how combined effects of collisions and dephasing can lead to thermalization, with implications for modeling quantum systems at equilibrium.

Contribution

It introduces a broad class of quantum maps that model collisional reservoirs and demonstrates how their combination with dephasing induces thermalization.

Findings

Low collision rate enables thermalization through combined effects.

Conditions for these maps to arise are identified within scattering theory.

The process models collisional reservoirs at equilibrium.

Abstract

We introduce a wide class of quantum maps that arise in collisional reservoirs and are able to thermalize a system if they operate in conjunction with an additional dephasing mechanism. These maps describe the effect of collisions and induce transitions between populations that obey detailed balance, but also create coherences that prevent the system from thermalizing. We combine these maps with a unitary evolution acting during random Poissonian times between collisions and causing dephasing. We find that, at a low collision rate, the nontrivial combination of these two effects causes thermalization in the system. This scenario is suitable for modeling collisional reservoirs at equilibrium. We justify this claim by identifying the conditions for such maps to arise within a scattering theory approach and provide a thorough characterization of the resulting thermalization process.