Scaling in the Fan of an Unconventional Quantum Critical Point

TL;DR

This study uses large-scale Quantum Monte Carlo simulations to investigate a quantum antiferromagnet with four-spin interactions, revealing an unconventional quantum critical point consistent with deconfined quantum criticality.

Contribution

It demonstrates that four-spin interactions induce a novel quantum critical point, supporting the deconfined quantum criticality scenario in a sign-problem-free model.

Findings

Four-spin interactions destroy Néel order at a z=1 quantum critical point.

Results support the deconfined quantum criticality scenario.

Simulations conducted on large lattices with over 16,000 spins.

Abstract

We present results of extensive finite-temperature Quantum Monte Carlo simulations on a SU(2) symmetric S=1/2 quantum antiferromagnet with a four-spin interaction [Sandvik, Phys. Rev. Lett. 98, 227202 (2007)]. Our simulations, which are free of the sign-problem and carried out on lattices containing in excess of 1.6 X 10^4 spins, indicate that the four-spin interaction destroys the N\'eel order at an unconventional z=1 quantum critical point, producing a valence-bond solid paramagnet. Our results are consistent with the `deconfined quantum criticality' scenario.