1,252 research outputs found
Effects of Geometrical Symmetry on the Vortex Nucleation and Penetration in Mesoscopic Superconductors
We investigate how the geometrical symmetry affects the penetration and
arrangement of vortices in mesoscopic superconductors using self-consistent
Bogoliubov-de Gennes equations. We find that the entrance of the vortex happens
when the current density at the hot spots reaches the depairing current
density. Through determining the spatial distribution of hot spots, the
geometrical symmetry of the superconducting sample influences the nucleation
and entrance of vortices. Our results propose one possible experimental
approach to control and manipulate the quantum states of mesoscopic
superconductors with their topological geometries, and they can be easily
generalized to the confined superfluids and Bose-Einstein condensates
Dynamical Creation of Fractionalized Vortices and Vortex Lattices
We investigate dynamic creation of fractionalized half-quantum vortices in
Bose-Einstein condensates of sodium atoms. Our simulations show that both
individual half-quantum vortices and vortex lattices can be created in rotating
optical traps when additional pulsed magnetic trapping potentials are applied.
We also find that a distinct periodically modulated spin-density-wave spatial
structure is always embedded in square half-quantum vortex lattices; this
structure can be conveniently probed by taking absorption images of
ballistically expanding cold atoms in a Stern-Gerlach field.Comment: 4 pages, 3 figures; published versio
Superradiant Solid in Cavity QED Coupled to a Lattice of Rydberg Gas
We study an optical cavity coupled to a lattice of Rydberg atoms, which can
be represented by a generalized Dicke model. We show that the competition
between the atomic interaction and atom-light coupling induces a rich phase
diagram. A novel "superradiant solid" (SRS) phase is found, where both the
superradiance and crystalline orders coexist. Different from the normal second
order superradiance (SR) transition, here both the Solid-1/2 and SRS to SR
phase transitions are first order. These results are confirmed by the large
scale quantum Monte Carlo simulations.Comment: 5 pages,4 figure
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