Persistent superfluid phase in a three-dimensional quantum XY model with ring exchange

TL;DR

This study uses quantum Monte Carlo simulations to explore a 3D quantum XY model with ring exchange, revealing a persistent superfluid phase that remains stable even at high ring exchange values.

Contribution

It demonstrates that the superfluid phase in a 3D quantum XY model with ring exchange persists without transitioning to other phases, challenging previous expectations.

Findings

Superfluid phase remains stable at high ring exchange values

No evidence of phase transition in the superfluid phase

Ground state properties characterized at zero temperature

Abstract

We present quantum Monte Carlo simulation results on a quantum S=1/2 XY model with ring exchange (the J-K model) on a three-dimensional simple cubic lattice. We first characterize the ground state properties of the pure XY model, obtaining estimations for the energy, spin stiffness and spin susceptibility at T=0 in the superfluid phase. With the ring exchange, we then present simulation data on small lattices which suggests that the superfluid phase persists to very large values of the ring exchange K, without signatures of a phase transition. We comment on the consequences of this result for the search for various exotic phases in three dimensions.