Multiple signatures of topological transitions for interacting fermions in chain lattices

TL;DR

This paper investigates topological phase transitions in interacting fermion chains with superconductivity, identifying multiple signatures in thermodynamic and pair-condensate properties, and analyzing their robustness and implications for Majorana fermions detection.

Contribution

It introduces multiple physical signatures for topological transitions in interacting fermion chains, enhancing detection methods and understanding of Majorana fermions in such systems.

Findings

Topological states are characterized by multiple signatures in thermodynamic quantities.

Disappearance of topological phase in a strongly attractive regime with a first-order transition.

Signatures remain stable against finite size, disorder, and inhomogeneity.

Abstract

We study one-component fermions in chain lattices with proximity-induced superconducting gap and interparticle short-range interaction, capable of hosting Majorana fermions. By systematically tracking various physical quantities, we show that topological states and topological phase transitions in the system can be identified by multiple signatures in thermodynamic quantities and pair-condensate properties, in good agreement with the known signatures in the ground-state energy and entanglement spectrum. We find the disappearance of the topological phase in a largely attractive regime, in which the system undergoes a first-order transition between two topologically trivial states. In addition, the stability of the signatures against finite size, disorder, and inhomogeneity is analyzed. Our results provide additional degrees of freedom for the characterization of topological states with interaction and for the experimental detection of emergent Majorana fermions.