An optimal superconducting hybrid machine

TL;DR

This paper investigates quantum hybrid thermal machines, demonstrating how quantum effects can surpass classical thermodynamic limits by reducing fluctuations and enabling multiple tasks in multiterminal conductors.

Contribution

It introduces generalized thermodynamic uncertainty relations for quantum multiterminal conductors and shows their violation in specific quantum systems like double quantum dots.

Findings

Quantum conductors can outperform classical limits in fluctuation suppression.

Hybrid quantum machines can perform multiple useful tasks simultaneously.

Demonstration of entangled Cooper pairs reducing fluctuations in quantum conductors.

Abstract

Optimal engine performances are accomplished by quantum effects. Here we explore two routes towards ideal engines, namely (1) quantum systems that operate as hybrid machines being able to perform more than one useful task and (2) the suppression of fluctuations in doing such tasks. For classical devices, the absence of fluctuations is conditioned by a high entropy production as dictate the thermodynamic uncertainty relations. Here we generalize such relations for multiterminal conductors that operate as hybrid thermal machines. These relations are overcome in quantum conductors as we demonstrate for a double quantum dot contacted to normal metals and a reservoir being a generator of entangled Cooper pairs.