Quantum Phase Transition in the Frustrated Heisenberg Antiferromagnet

TL;DR

This paper investigates the quantum phase transition in the frustrated Heisenberg antiferromagnet using the J_1-J_2 model and modified spin wave theory, highlighting the transition from Neel order to a spin-liquid state.

Contribution

It introduces a new theoretical framework for describing the quantum phase transition and provides a general expression for the spectral gap in the spin-liquid phase.

Findings

Identification of the phase transition point between Neel order and spin-liquid state.

Derivation of a general expression for the spectral gap in the spin-liquid phase.

Theoretical prediction of the spectral properties in the spin-liquid phase.

Abstract

Using the J_1-J_2 model, we present a description of quantum phase transition from Neel ordered to the spin-liquid state based on the modified spin wave theory. The general expression for the gap in the spectrum in the spin-liquid phase is presented.