Dynamics-induced freezing of strongly correlated ultracold bosons

We study the non-equilibrium dynamics of ultracold bosons in an optical lattice with a time-dependent hopping amplitude J(t) = J(0) + delta Jcos(omega t) which takes the system from a superfluid phase near the Mott-superfluid transition (J = J(0) + delta J) to a Mott phase (J = J(0) - delta J) and back through a quantum critical point (J - J(c)), and demonstrate dynamics-induced freezing of the boson wave function at specific values of omega. At these values, the wave function overlap F (defect density P = 1 - F) approaches unity (zero). We provide a qualitative explanation of the freezing phenomenon, show its robustness against quantum fluctuations and the presence of a trap, compute residual energy and superfluid order parameter for such dynamics, and suggest experiments to test our theory. Copyright (c) EPLA, 2012