Browsing by Author "Lu, Hong"

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    Numerical studies of ultracold atomic gases
    (2010) Lu, Hong; Pu, Han
    The experimental success in ultra-cold atomic gases, both bosonic and fermionic have boosted the theoretical studies, and especially the a lot of numerical techniques have been developed and used to describe them. In this thesis, we introduce two numerical experiments in our group on ultra-cold atomic gases. The first concerns the scalar dipolar condensate. We have developed and implemented a Split-Step Fourier scheme in imaginary time, which enable us to seek the ground state of the dipolar condensate. The second part is focused on our ongoing efforts to investigate the trapped spin polarized Fermi gas using self-consistent Bogoliubov-de Gennes (BdG) calculation.
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    Searching For FFLO States in Ultracold Polarized Fermi Gases: A Numerical Approach
    (2013-07-24) Lu, Hong; Pu, Han; Hulet, Randall G.; Warburton, Tim
    Ultracold atomic gases have emerged as an ideal laboratory system to emulate many-body physics in an unprecedentedly controllable manner. Numerous many-body quantum states and phases have been experimentally explored and characterized using the ultracold atomic gases, offering new insights into many exciting physics ranging from condensed matters to cosmology. In this thesis, we will present a systematic numerical study of a novel experimental system, population imbalanced two-component ultracold Fermi gases. We explore the phase diagram of this system in both 3D and 1D especially focusing on the exotic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase, which is characterized by a spatially oscillating order parameter. In 3D, we solve for the stationary states of trapped imbalanced Fermi gases in a wide range of parameter space with a home-made parallel eigen-solver for Bogoliubov-de Gennes (BdG) equations. Our results show that there exists a metastable state with a FFLO type oscillating order parameter. In 1D, we simulate the dynamical expansion of the population imbalanced Fermi gases from the trap. A numerically quasi-exact scheme, time-evolving block decimation (TEBD), is introduced for the comparative studies with the solution of the time-dependent BdG equation. Our results predict that the existence of FFLO states will leave conspicuous signatures in the density profiles during the expansion. For further understanding of the interplay between the population imbalance and two-body pairing interaction between two spin components, we also study the spin transport properties through trapped ultracold Fermi gases. The preliminary results will be discussed.