Kaleidoscope of exotic quantum phases in a frustrated XY model

TL;DR

This paper demonstrates that a frustrated XY model on a honeycomb lattice can host a Bose metal phase with a Bose surface, revealing complex quantum phases and phase transitions through exact diagonalization.

Contribution

It identifies and characterizes a Bose metal phase in a simple quantum spin model, advancing understanding of exotic quantum phases in frustrated systems.

Findings

Discovery of a Bose metal phase with a Bose surface

Identification of four distinct phases in the model

Three quantum phase transitions between these phases

Abstract

The existence of quantum spin liquids was first conjectured by Pomeranchuk some 70 years ago, who argued that frustration in simple antiferromagnetic theories could result in a Fermi-liquid-like state for spinon excitations. Here we show that a simple quantum spin model on a honeycomb lattice hosts the long sought for Bose metal with a clearly identifiable Bose surface. The complete phase diagram of the model is determined via exact diagonalization and is shown to include four distinct phases separated by three quantum phase transitions.