Dynamic transitions between metastable states in a superconducting ring

TL;DR

This study uses time-dependent Ginzburg-Landau equations to analyze how a superconducting ring transitions between metastable states under magnetic fields, revealing the roles of relaxation times in reaching thermodynamic equilibrium.

Contribution

It introduces a detailed analysis of the transition dynamics between metastable states in superconducting rings, emphasizing the influence of relaxation times on the final state.

Findings

Transition dynamics depend on relaxation time ratio tau_{|psi|} / tau_{phi}.

Larger ratio leads to states closer to thermodynamic equilibrium.

Transitions occur via phase slips at specific ring points.

Abstract

Applying the time-dependent Ginzburg-Landau equations, transitions between metastable states of a superconducting ring are investigated in the presence of an external magnetic field. It is shown that if the ring exhibits several metastable states at a particular magnetic field, the transition from one metastable state to another one is governed by both the relaxation time of the absolute value of the order parameter tau_{|psi|} and the relaxation time of the phase of the order parameter tau_{phi}. We found that the larger the ratio tau_{|psi|}tau_{phi} the closer the final state will be to the absolute minimum of the free energy, i.e. the thermodynamic equilibrium. The transition to the final state occurs through a subsequent set of single phase slips at a particular point along the ring.