Quantum phase transitions of 2-d dimerized spin-1/2 Heisenberg models with spatial anisotropy

TL;DR

This study investigates quantum phase transitions in 2D dimerized spin-1/2 Heisenberg models with spatial anisotropy, revealing that observed scaling corrections are likely due to amplified nonuniversal factors rather than altered critical exponents.

Contribution

It provides numerical evidence that enhanced corrections to scaling in these models are due to amplified nonuniversal prefactors, not changes in universal critical exponents.

Findings

Data compatible with O(3) universality class

Enhanced correction to scaling as amplification of nonuniversal factors

Numerical support for the scenario of correction amplification

Abstract

Motivated by the unexpected Monte Carlo results as well as the theoretical proposal of a large correction to scaling for the critical theory of the 2-d staggered-dimer spin-1/2 Heisenberg model on the square lattice, we study the phase transitions induced by dimerization of several dimerized quantum Heisenberg models with spatial anisotropy using first principles Monte Carlo method. Remarkably, while our Monte Carlo data for all the models considered here, including the herringbone- and ladder-dimer models on the square lattice, are compatible with the recently proposed scenario of an enhanced correction to scaling, we find it is likely that the enhanced correction to scaling manifests itself as amplification of the nonuniversal prefactors appeared in the scaling forms. In other words, our data are in consistence with the established numerical values for the critical exponents, including the confluent exponent, in the O(3) universality class. Convincing numerical evidence is provided to support this proposed scenario.