Performance boost of a collective qutrit refrigerator

TL;DR

This paper investigates how coupling multiple qutrit-based refrigerators enhances cooling performance, revealing a quantum boost that scales quadratically with the number of units, which can be maintained through fine-tuned interactions.

Contribution

It demonstrates the collective quantum boost in qutrit refrigerators and proposes methods to sustain this boost with inter-qutrit interactions.

Findings

Quadratic scaling of cooling current with number of qutrits

Transition from quadratic to linear scaling at large N

Fine-tuned interactions can preserve quantum boost

Abstract

A single qutrit with transitions selectively driven by weakly-coupled reservoirs can implement one of the world's smallest refrigerators. We analyze the performance of $N$ such fridges that are collectively coupled to the reservoirs. We observe a quantum boost, manifest in a quadratic scaling of the steady-state cooling current with $N$. As $N$ grows further, the scaling reduces to linear, since the transitions responsible for the quantum boost become energetically unfavorable. Fine-tuned inter-qutrit interactions may be used to maintain the quantum boost for all $N$ and also for not-perfectly collective scenarios.