Calorimetry of a phase slip in a Josephson junction

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. Here, 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.

Quantum thermodynamics with a single superconducting vortex

“…Our work and that presented in ( 13 ) both show that a phase slip event or vortex crossing the nanowire is responsible for substantial local dissipation leading to massive generation of QPs. This is the effect that is a priori neglected in well-established orthodox models of superconducting transitions of 1D nanowires ( 50 ), in which numerous phase slips, either thermal ( 51 , 52 ) or quantum ( 53 , 54 ), are fluctuations of the order parameter responsible for a finite resistance below T c .…”

“…Researchers were able to perform thermal imaging of a graphene with SQUID-on-tip and found the dissipation in resonant states along the edges of the sample ( 12 ). The other team measured a pronounced temperature rise in a nanoscopic metallic island serving as a junction in an RF-SQUIPT due to a single-phase slip event ( 13 ). Similar experiments are expected to deeply affect our understanding of the dynamics of the quantum systems, in which dissipation is responsible for the loss of the quantum coherence or suppression of topological protection.…”

Optimized proximity thermometer for ultrasensitive detection: Role of an ohmic electromagnetic environment

“…Finally, in order to calibrate our device, we have provided a simplified analytic view based on the linearized Usadel equation which is in good agreement with the full theory. This approach can be easily implemented as a calibration and optimization tool in future experiments in quantum calorimetry [34][35][36][37][38].…”

Heat Dissipation Mechanisms in Hybrid Superconductor–Semiconductor Devices Revealed by Joule Spectroscopy

“…Revealing and quantifying heat dissipation mechanisms as we do in this work provide a first step toward their control in devices for quantum applications and for basic research on quantum thermodynamics. 40,58 When finalizing the preparation of this manuscript, we became aware of this related work. 59 ■ ASSOCIATED CONTENT * sı Supporting Information…”

“…While these effects have been rather overlooked in relation to hybrid devices, they can have implications, for example, in geometries proposed for the realization of topological superconducting phases and related qubits. − ,, We note that while our experiment focuses on extreme conditions at which the superconducting elements of a device transit to the normal state, heating effects are even more pronounced for lower (AC/DC) applied powers, as both quasiparticle diffusion and electron–phonon coupling are suppressed with decreasing electron temperature. Revealing and quantifying heat dissipation mechanisms as we do in this work provide a first step toward their control in devices for quantum applications and for basic research on quantum thermodynamics. , …”