Quantum polarization spectroscopy of ultracold spinor gases
  We propose a method for the detection of ground state quantum phases of spinor gases through a series of two quantum nondemolition measurements performed by sending off-resonant, polarized light pulses through the gas. Signatures of various mean-field as well as strongly-correlated phases of F=1 and F=2 spinor gases obtained by detecting quantum fluctuations and mean values of polarization of transmitted light are identified. 
K. Eckert, L. Zawitkowski, A. Sanpera, M. Lewenstein, E.S. Polzik