Ian B. Spielman, Erhai Zhao, Noah Bray-Ali, Carl J. Williams, Indubala Satija
We present a novel technique for detecting topological invariants -- Chern numbers -- from time-of-flight images of ultra-cold neutral atoms. The Chern number of fermions in a lattice potential depends on magnetic field (for neutral atoms, generated by an artificial magnetic field) and the chemical potential; we find that the Chern numbers leave their fingerprints as oscillations in the atoms momentum distribution. The signature is strikingly enhanced for anisotropic hopping, where we show the momentum distribution assumes a sinusoidal form with period determined by the Chern number.
, Zhao, E.
, Bray-Ali, N.
, Williams, C.
and Satija, I.
Chern Numbers Hiding in Time-of-Flight Images, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevA.84.063629
(Accessed May 17, 2022)