Spectroscopy of a topological phase

TL;DR

This paper investigates the dynamical correlation functions of the toric code in a magnetic field, revealing rich field-dependent features and bound states that influence the system's excitations within the topological phase.

Contribution

It provides a detailed analysis of the dynamical correlations and bound states in the toric code under a magnetic field, highlighting their experimental relevance and spectral significance.

Findings

Identification of two-quasiparticle bound states across various magnetic fields

Bound states can be the lowest-energy excitations in the system

Rich field-dependent features in dynamical correlation functions

Abstract

Dynamical correlation functions of the toric code in a uniform magnetic field are studied inside the topological phase, in the small-field limit. Such an experimentally measurable quantity displays rich field-dependent features that can be understood via the interplay of the kinetics and the interaction of the anyonic excitations. In particular, it is sensitive to the two-quasiparticle bound states that are present in the spectrum for a wide range of magnetic fields. Interestingly, such collective modes can even constitute the lowest-energy excitations of the system.