Peter Barmettler, Dario Poletti, Marc Cheneau, Corinna Kollath
We analyze the quench dynamics of a one-dimensional bosonic Mott insulator and focus on the time evolution of density correlations. For these we identify a pronounced propagation front, the velocity of which, once correctly extrapolated at large distances, can serve as a quantitative characteristic of the many-body Hamiltonian. In particular, the velocity allows distinguishing the weakly interacting regime, which is qualitatively well described by free bosons, from the strongly interacting one, in which pairs of distinct quasiparticles dominate the dynamics. In order to describe the latter case analytically, we introduce a general approximation to solve the Bose--Hubbard Hamiltonian based on the Jordan--Wigner fermionization of auxiliary particles. This approach can also be used to determine the ground-state properties. Complementary to the fermionization approach, we derive explicitly the time-dependent many-body state in the non-interacting limit and compare our results to numerical simulations in the whole range of interactions of the Bose--Hubbard model.
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http://arxiv.org/abs/1202.5558
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