Dynamics-induced freezing of strongly correlated ultracold bosons

Abstract

We study the non-equilibrium dynamics of ultracold bosons in an optical lattice with a time-dependent hopping amplitude J(t) = J_0 + δJcos(ωt) which takes the system from a superfluid phase near the Mott-superfluid transition (J = J_0 + δJ) to a Mott phase (J = J_0 − δJ) and back through a quantum critical point (J = Jc), and demonstrate dynamics-induced freezing of the boson wave function at specific values of ω. 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.

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