New Experiments for Spontaneous Vortex Formation in Josephson Tunnel Junctions

TL;DR

This paper presents improved experiments measuring the Zurek-Kibble scaling exponent in Josephson Tunnel Junctions, confirming the theoretical predictions about defect formation during phase transitions with precise temperature monitoring.

Contribution

The study introduces an enhanced experimental setup to accurately measure the Zurek-Kibble scaling exponent and the junction gap voltage temperature dependence in Josephson Tunnel Junctions.

Findings

Measured the Zurek-Kibble scaling exponent as approximately 0.5.

Achieved precise temperature monitoring during rapid quenches.

Validated theoretical predictions of defect formation in phase transitions.

Abstract

It has been argued by Zurek and Kibble that the likelihood of producing defects in a continuous phase transition depends in a characteristic way on the quench rate. In this paper we discuss an improved experiment for measuring the Zurek-Kibble scaling exponent $\sigma $ for the production of fluxons in annular symmetric Josephson Tunnel Junctions. We find $\sigma \simeq 0.5$. Further, we report accurate measurements of the junction gap voltage temperature dependence which allow for precise monitoring of the fast temperature variations during the quench.