Seeing topological order in time-of-flight measurements
  In this work we provide a general methodology to directly measure topological order in cold atom systems. As an application we propose the realisation of a characteristic topological model, introduced by Haldane, using optical lattices loaded with fermionic atoms in two internal states. We demonstrate that time-of-flight measurements directly reveal the topological order of the system in the form of momentum space skyrmions. 
E. Alba, X. Fernandez-Gonzalvo, J. Mur-Petit, J. K. Pachos, J. J.   Garcia-Ripoll
cond-mat.quant-gas quant-ph