TY - JOUR
T1 - Chern numbers hiding in time-of-flight images
JF - Physical Review A
Y1 - 2011
A1 - Erhai Zhao
A1 - Noah Bray-Ali
A1 - Carl J. Williams
A1 - I. B. Spielman
A1 - Indubala I. Satija
AB - We present a technique for detecting topological invariants -- Chern numbers -- from time-of-flight images of ultra-cold atoms. We show that the Chern numbers of integer quantum Hall states of lattice fermions leave their fingerprints in the atoms' momentum distribution. We analytically demonstrate that the number of local maxima in the momentum distribution is equal to the Chern number in two limiting cases, for large hopping anisotropy and in the continuum limit. In addition, our numerical simulations beyond these two limits show that these local maxima persist for a range of parameters. Thus, an everyday observable in cold atom experiments can serve as a useful tool to characterize and visualize quantum states with non-trivial topology.
VL - 84
UR - http://arxiv.org/abs/1105.3100v3
CP - 6
J1 - Phys. Rev. A
U5 - 10.1103/PhysRevA.84.063629
ER -