Topological transition between competing orders in quantum spin chains

TL;DR

This paper investigates quantum phase transitions between competing orders in one-dimensional spin chains, revealing a topological change in elementary excitations and characterizing the transition's universality class through numerical methods.

Contribution

It introduces a dual-field sine-Gordon model framework to analyze topological transitions between ordered phases in quantum spin chains.

Findings

Elementary excitations switch from one topological soliton to another at the transition.

Dynamical susceptibilities and entanglement entropy characterize the transition and its universality class.

The study discusses potential experimental realizations in condensed matter and cold atomic systems.

Abstract

We study quantum phase transitions between competing orders in one-dimensional spin systems. We focus on systems that can be mapped to a dual-field double sine-Gordon model as a bosonized effective field theory. This model contains two pinning potential terms of dual fields that stabilize competing orders and allows different types of quantum phase transition to happen between two ordered phases. At the transition point, elementary excitations change from the topological soliton of one of the dual fields to that of the other, thus it can be characterized as a topological transition. We compute the dynamical susceptibilities and the entanglement entropy, which gives us access to the central charge, of the system using a numerical technique of infinite time-evolving block decimation and characterize the universality class of the transition as well as the nature of the order in each phase. The possible realizations of such transitions in experimental systems both for condensed matter and cold atomic gases are also discussed.