Particle number fractionization of an atomic Fermi-Dirac gas in an optical lattice

TL;DR

This paper demonstrates that a two-species Fermi-Dirac atomic gas in an optical lattice can exhibit fractional particle number eigenvalues due to topologically nontrivial coupling, with controllable fractionalization.

Contribution

It introduces a method to induce and control particle number fractionization in an atomic Fermi gas using topologically nontrivial electromagnetic fields.

Findings

Fractional eigenvalues of the spin operator are achieved.

Fluctuations of the fractional eigenvalues vanish.

Fractionalization can be tuned via electromagnetic detuning.

Abstract

We show that a dilute 2-species gas of Fermi-Dirac alkali-metal atoms in a periodic optical lattice may exhibit fractionization of particle number when the two components are coupled via a coherent electromagnetic field with a topologically nontrivial phase profile. This results in fractional eigenvalues of the spin operator with vanishing fluctuations. The fractional part can be accurately controlled by modifying the effective detuning of the electromagnetic field.