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TT: Fachverband Tiefe Temperaturen
TT 69: Cold Atomic Gases and Superfluids
TT 69.3: Talk
Friday, April 5, 2019, 10:00–10:15, H23
Floquet induced superfluidity — •Shijie Hu1, Xue-Feng Zhang2, Tao Wang1,2,3, Axel Pelster1, and Sebastian Eggert1 — 1Technische Universität Kaiserslautern — 2Chongqing University — 3Wuhan Institute of Technology
We consider two states of hard-core bosons with periodically modulated Rabi driving in a one dimensional (1D) optical lattice, which is equivalent to the 1D Hubbard model with time-periodic interactions. Using Floquet theory the model can be mapped to an effective Hamiltonian for high frequencies, which is described by a static interactions and hopping parameters that depend on the local densities. In particular, if the density difference of one species is non-zero on neighboring sites, the effective hopping of the other species is reduced and can even take on negative values. Using a combination of analytic calculations and different advanced numerical simulations we establish the full quantum phase diagram for half-integer filling for this system. Surprisingly, the density-dependent reduction of hopping drives a quantum phase transition into a superfluid phase. For negative hopping a previously unknown state is found, where one species induces a gauge phase of the other species, which leads to a superfluid phase of gauge-dressed particles. The corresponding experimental signatures in time-of-flight experiments are calculated and show characteristic signatures of the different phases. The phase transition line between the two superfluid phases corresponds to an exactly solvable model with high degeneracy.