4e-condensation in a fully frustrated Josephson junction diamond chain

TL;DR

This paper investigates the transition from insulator to 4e-superfluid in a fully frustrated Josephson junction diamond chain, using Monte Carlo simulations to analyze critical behavior and compare with less frustrated cases.

Contribution

It provides a quantitative analysis of the insulator to 4e-superfluid transition and identifies the critical point in a fully frustrated Josephson junction chain.

Findings

Identification of the critical point for the 4e-superfluid transition

Behavior of phase-phase correlators in the transition

Comparison with standard 2e-condensation in less frustrated chains

Abstract

Fully frustrated one-dimensional diamond Josephson chains have been shown [B. Dou\c{c}ot and J. Vidal, Phys. Rev. Lett. {\bf 88}, 227005 (2002)] to posses a remarkable property: The superfluid phase occurs through the condensation of pairs of Cooper pairs. By means of Monte Carlo simulations we analyze quantitatively the Insulator to $4e$-Superfluid transition. We determine the location of the critical point and discuss the behaviour of the phase-phase correlators. For comparison we also present the case of a diamond chain at zero and 1/3 frustration where the standard $2e$-condensation is observed.