Resonant two-site tunneling dynamics of bosons in a tilted optical superlattice

Buyskikh, Anton S. and Tagliacozzo, Luca and Schuricht, Dirk and Hooley, Chris A. and Pekker, David and Daley, Andrew J. (2019) Resonant two-site tunneling dynamics of bosons in a tilted optical superlattice. Physical Review A, 100 (2). 023627. ISSN 1094-1622

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    Abstract

    We study the nonequilibrium dynamics of a one-dimensional Bose-Hubbard model in a gradient potential and a superlattice, beginning from a deep Mott insulator regime with an average filling of one particle per site. Studying a quench that is near resonance to tunneling of the particles over two lattice sites, we show how a spin model emerges consisting of two coupled Ising chains that are coupled by interaction terms in a staggered geometry. We compare and contrast the behavior in this case with that in a previously studied case where the resonant tunneling was over a single site. Using optimized tensor network techniques to calculate finite-temperature behavior of the model, as well as finite-size scaling for the ground state, we conclude that the universality class of the phase transition for the coupled chains is that of a tricritical Ising point. We also investigate the out-of-equilibrium dynamics after the quench in the vicinity of the resonance and compare dynamics with recent experiments realized without the superlattice geometry. This model is directly realizable in current experiments and reflects a general way to realize spin models with ultracold atoms in optical lattices.