Creating, probing, and manipulating fractionally charged excitations of fractional Chern insulators in optical lattices

TL;DR

This paper proposes methods to create and detect fractional charge excitations in fractional Chern insulators within optical lattices, supported by simulations showing charge fractionalization in small bosonic systems, advancing experimental realization prospects.

Contribution

It introduces schemes for creating and probing fractional excitations in optical lattice realizations of fractional Chern insulators, supported by numerical simulations.

Findings

Signatures of charge fractionalization observed in four-particle bosonic systems.

Feasibility of adiabatic preparation of fractional Chern insulators demonstrated.

Proposed methods align with recent experimental capabilities in atomic quantum gases.

Abstract

We propose a set of schemes to create and probe fractionally charged excitations of a fractional Chern insulator state in an optical lattice. This includes the creation of localized quasiparticles and quasiholes using both static local defects and the dynamical local insertion of synthetic flux quanta. Simulations of repulsively interacting bosons on a finite square lattice with experimentally relevant open boundary conditions show that already a four-particle system exhibits signatures of charge fractionalization in the quantum-Hall-like state at the filling fraction of $1/2$ particle per flux quantum. This result is favorable for the prospects of adiabatic preparation of fractional Chern insulators. Our work is inspired by recent experimental breakthroughs in atomic quantum gases: the realization of strong artificial magnetic fields in optical lattices, the ability of single-site addressing in quantum gas microscopes, and the preparation of low-entropy insulating states by engineering an entropy-absorbing metallic reservoir.