Title: | Floquet-Induced Superfluidity with Periodically Modulated Interactions of Two-Species Hardcore Bosons in a 1D Optical Lattice |

Speaker: | Dr. Shijie Hu |

Time: | 13:30 November 7 (Wednesday), 2018 |

Place: | TDLI Meeting Room 200 (East Wing of Pao Yue-kong Library) |

Host: | Prof. Xiaoqun Wang |

Abstract | Systems out of equilibrium usually exhibit novel physical phenomena. In this work, We consider two species of hard-core bosons (pseudo-spin-1/2) in a one-dimensional optical lattice with periodically modulated repulsive interactions. Using Floquet theory the periodic can be mapped to an effective Hamiltonian for high frequencies, which is described by a static interaction 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. Surprisingly, the density-dependent reduction of hopping drives a 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 signatures in time-of-flight experiments are calculated and show characteristic signatures of the different phases. Finally, we discuss behaviors of real-time dynamics. |

Biography | Dr. Shijie Hu, Technische Universita ̈t Kaiserslautern. In 2010, he obtained Ph.D degree from the Institute of Theoretical Physics, Chinese Academy of Sciences. He continued postdoctoral career at Go ̈ttingen University, Max-Planck Institute for Physics of Complex Systems and Technische Universita ̈t Kaiserslautern. His research includes development and applications of density-matrix (or transfer-matrix) renormalization group methods and other tensor-network algorithms on the strongly-correlated quantum systems. |