Generic mixed columnar-plaquette phases in Rokhsar-Kivelson models

TL;DR

This paper investigates the phase diagram of Rokhsar-Kivelson models, revealing a generic mixed phase interpolating between columnar and plaquette states, supported by numerical evidence in the square lattice quantum dimer model.

Contribution

It introduces a unified phase diagram with a mixed phase in Rokhsar-Kivelson models, supported by numerical analysis, resolving previous disagreements.

Findings

Identification of a mixed phase interpolating between columnar and plaquette states

Numerical evidence from exact diagonalization and Monte Carlo methods

Analysis of excitation gaps and structure factors supports the mixed phase scenario

Abstract

We revisit the phase diagram of Rokhsar-Kivelson models, which are used in fields such as superconductivity, frustrated magnetism, cold bosons, and the physics of Josephson junction arrays. From an extended height effective theory, we show that one of two simple generic phase diagrams contains a mixed phase that interpolates continuously between columnar and plaquette states. For the square lattice quantum dimer model we present evidence from exact diagonalization and Green's function Monte Carlo techniques that this scenario is realised, by combining an analysis of the excitation gaps of different symmetry sectors with information on plaquette structure factors. This presents a natural framework for resolving the disagreement between previous studies.