Topological phases and Edge states in an exactly solvable Gamma matrix model

TL;DR

This paper analyzes an exactly solvable 1D Gamma matrix model revealing a rich phase diagram with topological phases, edge states, and critical behavior, classified within the CII symmetry class.

Contribution

It identifies symmetry-protected topological phases and Majorana edge modes in an exactly solvable Gamma matrix model, expanding understanding of topological phases in 1D systems.

Findings

Presence of topological phases with integer winding numbers

Existence of localized zero-energy Majorana edge modes

Critical scaling and universality at phase transitions

Abstract

We study the phases of an exactly solvable one dimensional model with $4-$dimensional $\Gamma-$matrix degrees of freedom on each site. The $\Gamma-$matrix model has a large set of competing interactions and displays a rich phase diagram with critical lines and multi-critical points. We work with the model with certain $Z_2$ symmetries and identify the allowed symmetry protected topological phases using the winding number as the topological invariant. The model belongs to the CII-class of the $10-$fold classification and allows for integer values of the winding number. We confirm that the system also hosts localized zero energy Majorana edge modes, consistent with the integer value of the winding number of the corresponding phase. We further study scaling and universality behaviour of the various topological phase transitions.