Large-N estimates of universal amplitudes of the CP^{N-1} theory and comparison with the JQ model

TL;DR

This paper computes universal amplitude ratios in the large-N limit of the CP^{N-1} field theory and compares these theoretical predictions with quantum Monte Carlo data for the JQ model near the Neel-VBS transition.

Contribution

It provides the first large-N estimates of universal amplitudes for the CP^{N-1} theory and compares these with numerical data from the JQ model.

Findings

Universal amplitude ratios match well between theory and simulations.

Large-N calculations offer insights into critical behavior of quantum antiferromagnets.

Results support the field theory description of the Neel-VBS transition.

Abstract

We present computations of certain finite-size scaling functions and universal amplitude ratios in the large-N limit of the CP^{N-1} field theory. We pay particular attention to the uniform susceptibility, the spin stiffness and the specific heat. Field theoretic arguments have shown that the long-wavelength description of the phase transition between the Neel and valence bond solid states in square lattice S=1/2 anti-ferromagnets is expected to be the non-compact CP^1 field theory. We provide a detailed comparison between our field theoretic calculations and quantum Monte Carlo data close to the Neel -VBS transition on a S=1/2 square-lattice model with competing four-spin interactions (the JQ model).