Necessarily transient quantum refrigerator

TL;DR

This paper demonstrates that small-scale quantum refrigerators can achieve cooling only during transient dynamics without steady-state cooling, highlighting the role of interaction parameters and quantum correlations.

Contribution

It introduces a canonical form of qubit-bath interactions enabling transient-only cooling and shows this phenomenon is generic in quantum absorption refrigerators.

Findings

Transient cooling can occur without steady-state cooling.

Minimal quantum correlations are associated with transient cooling.

The minimum temperature can remain nearly constant over a range of parameters.

Abstract

We show that one can construct a quantum absorption refrigerator that provides refrigeration only in the transient regime, by using three interacting qubits, each of which is also interacting with local heat-bath. The machine either does not provide cooling in the steady state, or the steady state is achieved after a long time. We propose a canonical form of qubit-bath interaction parameters that generates transient cooling without steady-state cooling, and claim that such a phenomenon is generic to small-scale quantum absorption refrigerators. We also show that it is generically possible to have fast cooling. We demonstrate our results for two separate models of thermalization, and show that a transient cooling without steady-state cooling is associated with generation of negligible, or no bipartite quantum correlations. For one of the models of thermalization, we find that the minimum achievable temperature of the refrigerated qubit can remain almost frozen, i.e., unchanged, for a significant region of the parameter space.