Optimal performance of endoreversible quantum refrigerators

TL;DR

This paper derives the maximum cooling performance of endoreversible quantum refrigerators, revealing that the optimal performance depends on specific system-bath interactions rather than universal principles, with an analytical benchmark provided.

Contribution

It provides a complete microscopic derivation of the performance bounds for quantum refrigerators, highlighting the role of system-bath interactions in determining optimal cooling.

Findings

Cooling performance at maximum power depends on system-bath interaction details.

An analytical benchmark for weakly coupled bosonic heat baths is established.

Contrasts the universality of heat engine efficiency with the specificity of quantum refrigerator performance.

Abstract

The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results which are model-independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for \textit{any} endoreversible quantum refrigerator. At striking variance with the \textit{universality} of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics.