Detecting Topological Phases in Ultracold Atomic Gases with Strong Interactions

We propose a generic scheme to unambiguously probe topological invariants in ultracold-atomic systems using momentum-resolved Raman or radio-frequency spectroscopy. The method is based on Green's function formulations and is applicable to a wide range of topological states in arbitrary spatial dimensions with or without strong interactions. Using an interacting one-dimensional topological insulator as an example, we further demonstrate that the scheme is robust against realistic experimental imperfections, such as the inhomogeneous trapping potential and limited experimental resolution.