Topological quantum pump of strongly interacting fermions in coupled chains

TL;DR

This paper investigates a topological quantum pump in a model of strongly interacting fermions on coupled chains, demonstrating opposite pumping directions for particles and pairs, with quantized charge linked to a many-body Chern number.

Contribution

It introduces a model where strongly interacting fermions exhibit topologically quantized pumping with opposite directions for particles and pairs, highlighting the role of many-body topology.

Findings

Single particles and pairs are pumped in opposite directions.

The pumped charge is exactly quantized and related to a many-body Chern number.

The model demonstrates topologically non-trivial paths for adiabatic parameter variation.

Abstract

We analyze a tight binding model of two coupled chains with strongly interacting fermions. Depending on the parameter $w$, the many body lowest energy band consists of either single particles or bound pairs. A topological quantum pump can be created by periodically varying the coupling strengths under adiabatic conditions. We numerically show that the single particles and bound pairs are pumped in opposite directions along topologically non-trivial paths. The exact quantization of the pumped charge can be expressed by a (many body) Chern number.