Novel massless phase of Haldane-gap antiferromagnets in magnetic field

TL;DR

This paper explores a new massless phase in Haldane-gap antiferromagnets under magnetic fields, revealing a two-component Luttinger liquid phase that emerges from incommensurate fluctuations, differing from conventional models.

Contribution

It identifies and characterizes a novel two-component Luttinger liquid phase in Haldane-gap antiferromagnets under magnetic fields, expanding understanding of their low-energy behavior.

Findings

Discovery of a two-component Luttinger liquid phase

Existence of incommensurate fluctuations in the ground state

Phase appears above the Haldane-gap and other massive phases

Abstract

The behavior of Haldane-gap antiferromagnets in strong magnetic field is not universal. While the low-energy physics of the conventional 1D spin-1 Heisenberg model in its magnetized regime is described by one incommensurate soft mode, other systems with somewhat perturbed coupling constants can possess two characteristic soft modes in a certain range of the field strength. Such a {\em two}-component Lutinger liquid phase is realised above the massive Haldane-gap phase, and in general above any massive nonmagnetic phase, when the ground state exhibits short range incommensurate fluctuations already in the absence of the field.