Dynamic transitions and resonances in Josephson-junction arrays under oscillating magnetic fields

TL;DR

This paper studies how two-dimensional Josephson-junction arrays respond dynamically to oscillating magnetic fields, revealing phase transitions and stochastic resonance phenomena influenced by temperature and driving field strength.

Contribution

It uncovers the nature of dynamic phase transitions and resonance effects in Josephson-junction arrays under oscillating magnetic fields, highlighting deviations from universality at high driving amplitudes.

Findings

Dynamic order parameter becomes nonzero at low temperatures.

Transition follows the same universality as the equilibrium Z_2 transition at small fields.

Stochastic resonance peak appears above the transition temperature.

Abstract

We investigate dynamic transitions and stochastic resonance phenomena in two-dimensional fully frustrated Josephson-junction arrays driven by staggered oscillating magnetic fields. As the temperature is lowered, the dynamic order parameter, defined to be the average staggered magnetization, is observed to acquire nonzero values. The resulting transition is found to belong to the same universality as the equilibrium Z_2 transition for small driving amplitudes while large driving fields appear to induce deviation from the universality class. The transition is also manifested by the stochastic resonance peak of the signal-to-noise ratio, which develops above the transition temperature.