Self-Trapped Polarons and Topological Defects in a Topological Mott Insulator

TL;DR

This paper explores how many-body interactions in a topological Mott insulator lead to complex spatial features like polarons and domain walls, which host topologically protected states, with potential realization in Rydberg atom quantum simulators.

Contribution

It introduces the emergence of self-trapped polarons and topological defects in a topological Mott insulator, revealing new interplay between interactions and topology.

Findings

Interaction-induced quantum anomalous Hall phase identified

Self-trapped polarons and domain walls observed at incommensurate fillings

Domain walls host topologically protected chiral edge states

Abstract

Many-body interactions in topological quantum systems can give rise to new phases of matter, which simultaneously exhibit both rich spatial features and topological properties. In this work, we consider spinless fermions on a checkerboard lattice with nearest and next-to-nearest neighbor interactions. We calculate the phase diagram at half filling, which presents, in particular, an interaction-induced quantum anomalous Hall phase. We study the system at incommensurate fillings using an unrestricted Hartree-Fock ansatz and report a rich zoo of solutions such as self-trapped polarons and domain walls above an interaction-induced topological insulator. We find that, as a consequence of the interplay between the interaction-induced topology and topological defects, these domain walls separate two phases with opposite topological invariants and host topologically protected chiral edge states. Finally, we discuss experimental prospects to observe these novel phenomena in a quantum simulator based on laser-dressed Rydberg atoms in an optical lattice.