Small quantum absorption refrigerator in the transient regime: time scales, enhanced cooling and entanglement

TL;DR

This paper investigates a three-qubit quantum absorption refrigerator in the transient regime, revealing enhanced cooling and increased entanglement compared to steady-state, with implications for quantum thermal machine design.

Contribution

It demonstrates that transient dynamics can improve cooling and entanglement in a quantum refrigerator without precise control, highlighting new operational regimes.

Findings

Transient cooling can surpass steady-state limits.

Entanglement is significantly larger in the transient regime.

Enhanced performance occurs even with strong damping.

Abstract

A small quantum absorption refrigerator, consisting of three qubits, is discussed in the transient regime. We discuss time scales for coherent dynamics, damping, and approach to the steady state, and we study cooling and entanglement. We observe that cooling can be enhanced in the transient regime, in the sense that lower temperatures can be achieved compared to the steady-state regime. This is a consequence of coherent dynamics, but can occur even when this dynamics is strongly damped by the dissipative thermal environment, and we note that precise control over couplings or timing is not needed to achieve enhanced cooling. We also show that the amount of entanglement present in the refrigerator can be much larger in the transient regime compared to the steady-state. These results are of relevance to future implementations of quantum thermal machines.