Creation and dynamics of remote spin-entangled pairs in the expansion of strongly correlated fermions in an optical lattice

We consider the nonequilibrium dynamics of an interacting spin-1/2 fermion gas in a one-dimensional optical lattice after switching off the confining potential. In particular, we study the creation and the time evolution of spatially separated, spin-entangled fermionic pairs. The time-dependent density-matrix renormalization group is used to simulate the time evolution and evaluate the two-site spin correlation functions, from which the concurrence is calculated. We find that the typical distance between entangled fermions depends crucially on the onsite interaction strength, and that a time-dependent modulation of the tunneling amplitude can enhance the production of spin-entanglement. Moreover, we discuss the prospects of experimentally observing these phenomena using spin-dependent single-site detection.