Transition by Breaking of Analyticity in the Ground State of Josephson Junction Arrays as a Static Signature of the Vortex Jamming Transition

TL;DR

This paper studies the ground state of irrationally frustrated Josephson junction arrays, revealing an analyticity-breaking transition at isotropy linked to vortex jamming, with critical scaling laws and metastable states.

Contribution

It uncovers a transition in the ground state analogous to the Aubry transition, connecting it to vortex jamming and identifying critical behavior and metastable states.

Findings

Analyticity breaking in the hull function at mbda=1

Scaling law for the harmonic spectrum indicating a diverging length scale

Connection between ground state transition and vortex jamming in simulations

Abstract

We investigate the ground state of the irrationally frustrated Josephson junction array with controlling anisotropy parameter \lambda\ that is the ratio of the longitudinal Josephson coupling to the transverse one. We find that the ground state has one dimensional periodicity whose reciprocal lattice vector depends on \lambda\ and is incommensurate with the substrate lattice. Approaching the isotropic point, \lambda=1 the so called hull function of the ground state exhibits analyticity breaking similar to the Aubry transition in the Frenkel-Kontorova model. We find a scaling law for the harmonic spectrum of the hull functions, which suggests the existence of a characteristic length scale diverging at the isotropic point. This critical behavior is directly connected to the jamming transition previously observed in the current-voltage characteristics by a numerical simulation. On top of the ground state there is a gapless, continuous band of metastable states, which exhibit the same critical behavior as the ground state.