Quantum Memory Assisted Probing of Dynamical Spin Correlations
  We propose a method to probe time dependent correlations of non trivial observables in many-body ultracold lattice gases. The scheme uses a quantum non-demolition matter-light interface, first, to map the observable of interest on the many body system into the light and, then, to store coherently such information into an external system acting as a quantum memory. Correlations of the observable at two (or more) instances of time are retrieved with a single final measurement that includes the readout of the quantum memory. Such method brings at reach the study of dynamics of many-body systems in and out of equilibrium by means of quantum memories in the field of quantum simulators. 
O. Romero-Isart, M. Rizzi, C. A. Muschik, E. S. Polzik, M. Lewenstein,   A. Sanpera
quant-ph cond-mat.quant-gas