Frustrated Heisenberg antiferromagnets: fluctuation induced first order vs deconfined quantum criticality

TL;DR

This paper introduces a new lattice-respecting renormalization method for frustrated quantum magnets, revealing a fluctuation-induced first order transition that may explain observed weakly first order behaviors in $S=1/2$ systems, contrasting with deconfined criticality.

Contribution

A novel renormalization approach respecting lattice structure, uncovering fluctuation-induced first order transitions in frustrated quantum magnets.

Findings

Identified fluctuation-induced first order transition in large spin systems.

Suggested this mechanism explains weakly first order behavior in $S=1/2$ frustrated systems.

Contrasts with deconfined quantum criticality scenarios.

Abstract

Recently it was argued that quantum phase transitions can be radically different from classical phase transitions with as a highlight the 'deconfined critical points' exhibiting fractionalization of quantum numbers due to Berry phase effects. Such transitions are supposed to occur in frustrated ('$J_1$-$J_2$') quantum magnets. We have developed a novel renormalization approach for such systems which is fully respecting the underlying lattice structure. According to our findings, another profound phenomenon is around the corner: a fluctuation induced (order-out-of-disorder) first order transition. This has to occur for large spin and we conjecture that it is responsible for the weakly first order behavior recently observed in numerical simulations for frustrated $S=1/2$ systems.