Calorimetry of a Quantum Phase Slip

TL;DR

This paper reports the first direct detection of heat released during a quantum phase slip in a Josephson junction, advancing understanding of dissipation in quantum superconducting devices.

Contribution

It experimentally observes heat release from a quantum phase slip using time-resolved electron thermometry, a novel approach in quantum thermodynamics.

Findings

Detected heat release during a quantum phase slip.

Demonstrated local electronic temperature increase and relaxation.

Established a new method for studying dissipation in quantum systems.

Abstract

In a Josephson junction, which is the central element in superconducting quantum technology, irreversibility arises from abrupt slips of the gauge-invariant quantum phase difference across the contact. A quantum phase slip (QPS) is often visualized as the tunneling of a flux quantum in the transverse direction to the superconducting weak link, which produces dissipation. In this work, we detect the instantaneous heat release caused by a QPS in a Josephson junction using time-resolved electron thermometry on a nanocalorimeter, signaled by an abrupt increase of the local electronic temperature in the weak link and subsequent relaxation back to equilibrium. Beyond providing a cornerstone in experimental quantum thermodynamics in form of observation of heat in an elementary quantum process, this result sets the ground for experimentally addressing the ubiquity of dissipation, including that in superconducting quantum sensors and qubits.