Electronic Refrigeration at the Quantum Limit

TL;DR

This paper demonstrates quantum-limited electronic refrigeration of a metallic island via impedance matching, enabling cooling at a distance through superconducting leads, and explores the transition between electromagnetic and quasiparticle heat transport.

Contribution

It introduces a method for quantum-limited refrigeration at a distance using impedance matching and analyzes heat transport mechanisms in superconducting circuits.

Findings

Refrigeration at a distance of about 50 micrometers achieved.

Cooling power determined by the quantum of thermal conductance.

Crossover between electromagnetic and quasiparticle heat flux observed and analyzed.

Abstract

We demonstrate quantum limited electronic refrigeration of a metallic island in a low temperature micro-circuit. We show that matching the impedance of the circuit enables refrigeration at a distance, of about 50 um in our case, through superconducting leads with a cooling power determined by the quantum of thermal conductance. In a reference sample with a mismatched circuit this effect is absent. Our results are consistent with the concept of electromagnetic heat transport. We observe and analyze the crossover between electromagnetic and quasiparticle heat flux in a superconductor.