Fractional charge pumping of interacting bosons in one-dimensional superlattice

TL;DR

This paper proposes a method for adiabatic fractional charge pumping in interacting bosonic systems within one-dimensional superlattices, demonstrating quantized fractional charge transfer linked to topological invariants.

Contribution

It introduces a novel approach for fractional charge pumping in interacting bosons, extending previous integer quantized pumping to fractional values through adiabatic modulation.

Findings

Charge pumping is quantized to fractional values related to Chern numbers.

The difference in charge polarization between ground states is quantized, indicating fractional quasiparticle charge.

The method applies to systems with certain fractional fillings, demonstrating topological fractionalization.

Abstract

Motivated by experimental realizations of integer quantized charge pumping in one-dimensional superlattices~[Nat. Phys. 12, 350 (2016); Nat. Phys. 12, 296 (2016)], we generalize and propose the adiabatic pumping of a fractionalized charge in interacting bosonic systems. This is achieved by dynamically sweeping the modulated potential in a class of one-dimensional interacting systems. As concrete examples, we show the charge pumping of interacting bosons at certain fractionally occupied fillings. We find that, for a given ground state, the charge pumping in a complete potential cycle is quantized to the fractional value related to the corresponding Chern number, characterized by the motion of the charge polarization per site. Moreover, the difference between charge polarizations of two ground states is quantized to an intrinsic constant revealing the fractional elementary charge of quasiparticle.