Field-induced topological pair-density wave states in a multilayer optical lattice

We study the superfluid phases of a Fermi gas in a multilayer optical lattice system in the presence of out-of-plane Zeeman field, as well as spin-orbit (SO) coupling. We show that the Zeeman field combined with the SO coupling leads to exotic topological pair-density wave (PDW) phases in which different layers possess different superfluid order parameters, even though each layer experiences the same Zeeman field and the SO coupling. We elucidate the mechanism of the emerging PDW phases, and characterize their topological properties by calculating the associated Chern numbers.Comment: 7 pages, 6 figures, accepted by Phys. Rev.

3D data fusion by depth refinement and pose recovery

Refining depth maps from different sources to obtain a refined depth map, and aligning the rigid point clouds from different views, are two core techniques. Existing depth fusion algorithms do not provide a general framework to obtain a highly accurate depth map. Furthermore, existing rigid point cloud registration algorithms do not always align noisy point clouds robustly and accurately, especially when there are many outliers and large occlusions. In this thesis, we present a general depth fusion framework based on supervised, semi-supervised, and unsupervised adversarial network approaches. We show that the refined depth maps are more accurate than the source depth maps by depth fusion. We develop a new rigid point cloud registration algorithm by aligning two uncertainty-based Gaussian mixture models, which represent the structures of the two point clouds. We show that we can register rigid point clouds more accurately over a larger range of perturbations. Subsequently, the new supervised depth fusion algorithm and new rigid point cloud registration algorithm are integrated into the ROS system of a real gardening robot (called TrimBot) for practical usage in real environments. All the proposed algorithms have been evaluated on multiple existing datasets to show their superiority compared to prior work in the field

Synthetic Landau levels and spinor vortex matter on Haldane spherical surface with magnetic monopole

We present a flexible scheme to realize exact flat Landau levels on curved spherical geometry in a system of spinful cold atoms. This is achieved by Floquet engineering of a magnetic quadrupole field. We show that a synthetic monopole field in real space can be created. We prove that the system can be exactly mapped to the electron-monopole system on sphere, thus realizing Haldane's spherical geometry for fractional quantum Hall physics. The scheme works for either bosons or fermions. We investigate the ground state vortex pattern for an $s$-wave interacting atomic condensate by mapping this system to the classical Thompson's problem. We further study the distortion and stability of the vortex pattern when dipolar interaction is present. Our scheme is compatible with current experimental setup, and may serve as a promising route of investigating quantum Hall physics and exotic spinor vortex matter on curved space.Comment: 11 pages, 4 figure

Two-component polariton condensate in optical microcavity

We present a scheme for engineering the extended two-component Bose-Hubbard model using polariton condensate supported by optical microcavity. Compared to the usual two-component Bose-Hubbard model with only Kerr nonlinearity, our model includes a nonlinear tunneling term which depends on the number difference of the particle in the two modes. In the mean field treatment, this model is an analog to a nonrigid pendulum with a variable pendulum length whose sign can be also changed. We study the dynamic and ground state properties of this model and show that there exists a first-order phase transition as the strength of the nonlinear tunneling rate is varied. Furthermore, we propose a scheme to obtain the polariton condensate wave function.Comment: 9 pages, 8 figure

Dynamically manipulating topological physics and edge modes in a single degenerate optical cavity

We propose a scheme to simulate topological physics within a single degenerate cavity, whose modes are mapped to lattice sites. A crucial ingredient of the scheme is to construct a sharp boundary so that the open boundary condition can be implemented for this effective lattice system. In doing so, the topological properties of the system can manifest themselves on the edge states, which can be probed from the spectrum of an output cavity field. We demonstrate this with two examples: a static Su-Schrieffer-Heeger chain and a periodically driven Floquet topological insulator. Our work opens up new avenues to explore exotic photonic topological phases inside a single optical cavity.Comment: 6 pages, 5 figure