Many-body Majorana-like zero modes without gauge symmetry breaking

TL;DR

This paper shows that Majorana-like zero modes can exist in many-body systems without gauge symmetry breaking or superconducting order, expanding the understanding of topological excitations beyond traditional superconductors.

Contribution

It introduces a new class of many-body zero modes that are robust and connected to Majorana modes, without requiring gauge symmetry breaking or superconductivity.

Findings

Zero modes emerge without gauge symmetry breaking

Majorana zero modes are connected to these many-body zero modes

A bosonization formalism is used to analyze these excitations

Abstract

Topological superconductors represent one of the key hosts of Majorana-based topological quantum computing. Typical scenarios for one-dimensional topological superconductivity assume a broken gauge symmetry associated to a superconducting state. However, no interacting one-dimensional many-body system is known to spontaneously break gauge symmetries. Here, we show that zero modes emerge in a many-body system without gauge symmetry breaking and in the absence of superconducting order. In particular, we demonstrate that Majorana zero modes of the symmetry-broken superconducting state are continuously connected to these zero-mode excitations, demonstrating that zero-bias anomalies may emerge in the absence of gauge symmetry breaking. We demonstrate that these many-body zero modes share the robustness features of the Majorana zero modes of symmetry-broken topological superconductors. We introduce a bosonization formalism to analyze these excitations and show that a ground state analogous to a topological superconducting state can be analytically found in a certain limit. Our results demonstrate that robust Majorana-like zero modes may appear in a many-body systems without gauge symmetry breaking, thus introducing a family of protected excitations with no single-particle analogs.