Charge Frustration Effects in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays

TL;DR

This paper explores quantum phase transitions in charge-frustrated, capacitively coupled 2D Josephson-junction arrays, revealing potential transitions from charge-density wave to super-solid phases near maximal frustration.

Contribution

It maps the system onto anisotropic Heisenberg models and proposes a new quantum phase transition to a super-solid phase under charge frustration.

Findings

Potential quantum phase transition from charge-density wave to super-solid phase.

System effectively described by a single quantum phase model near critical lines.

Charge frustration influences the emergence of long-range order in the system.

Abstract

We investigate the quantum phase transitions in two capacitively coupled two-dimensional Josephson-junction arrays with charge frustration. The system is mapped onto the S=1 and $S=1/2$ anisotropic Heisenberg antiferromagnets near the particle-hole symmetry line and near the maximal-frustration line, respectively, which are in turn argued to be effectively described by a single quantum phase model. Based on the resulting model, it is suggested that near the maximal frustration line the system may undergo a quantum phase transition from the charge-density wave to the super-solid phase, which displays both diagonal and off- diagonal long-range order.