Novel approach to description of spin liquid phases in low-dimensional quantum antiferromagnets

TL;DR

This paper introduces a novel analytical approach to describe spin liquid phases in low-dimensional quantum antiferromagnets, focusing on dimerized systems and their triplet excitations, with results matching numerical data.

Contribution

It presents a new analytical method using a dilute Bose gas of triplets to study spin liquids, extending understanding of quantum critical points in dimerized antiferromagnets.

Findings

Analytic triplet gap calculations agree with numerical results.

Excitation spectrum matches dimer series expansion data.

Identifies quantum critical point accurately.

Abstract

We consider quantum spin systems with dimerization, which at strong coupling have singlet ground states. To account for strong correlations, the excitations are described as dilute Bose gas of degenerate triplets with infinite on-site repulsion. This approach is applied to the two-layer Heisenberg model at zero temperature with general couplings. Our analytic results for the triplet gap, the excitation spectrum and the location of the quantum critical point are in excellent agreement with numerical results, obtained by dimer series expansions.