Unique Signatures of Topological Phases in Two-Dimensional THz Spectroscopy

TL;DR

This paper develops a microscopic theory for 2D THz spectroscopy of topological superconductors, showing that spectral signatures can identify topological phases in bulk properties without boundary mode interference.

Contribution

It introduces a novel theoretical framework demonstrating how 2D spectroscopy reveals topological phases in bulk superconducting systems.

Findings

2D spectra exhibit unique signatures of topological phases.

Spectroscopy distinguishes topological from trivial phases.

Bulk properties can be used to identify topological states.

Abstract

We develop a microscopic theory for the two-dimensional spectroscopy of one-dimensional topological superconductors. We consider a ring geometry as a realization of the Kitaev chain with periodic boundary conditions. We show numerically and analytically that the cross-peak structure of the 2D spectra carries unique signatures of the topological phases of the chain. Our work reveals how 2D spectroscopy can identify topological phases in bulk properties, bypassing energy-specific differences caused by topologically protected or trivial boundary modes that are otherwise hard to distinguish.