Ground state fluctuations in rung-dimerised spin ladders

TL;DR

This paper analytically investigates quantum fluctuations in spin ladders with slight rung-dimerization disruption, providing explicit formulas for triplet density and ground state energy, aligning with numerical results under certain conditions.

Contribution

It introduces an analytical approach to quantify quantum fluctuations in nearly rung-dimerized spin ladders, extending understanding beyond numerical methods.

Findings

Analytic expressions for triplet density and ground state energy derived.

Results agree with numerical calculations at high frustration and strong rung coupling.

Provides insights into quantum fluctuations in perturbed spin ladder systems.

Abstract

Treating an exactly rung-dimerized spin ladder as a reference model we study perturbatively zero temperature quantum fluctuations in spin ladders with slightly destroyed rung-dimerization. Analytic expressions are obtained for the gas parameter (density of rung-triplets) and the ground state energy per rung. At a strong diagonal frustration as well as at a rather strong antiferromagnetic rung coupling these results well agree with the previous numerical calculations.