We study the approach to equilibrium of a Bose gas to a superfluid state. We point out that dynamic scaling, characteristic of far from equilibrium phase-ordering systems, should hold. We stress the importance of a nondissipative Josephson precession term in driving the system to a new universality class. A model of coarsening in dimension d52, involving a quench between two temperatures below ...

We investigate theoretically and numerically a model of a supersolid in a dipole-blockaded Bose-Einstein condensate. The dependence of the superfluid fraction with an imposed thermal bath and a uniform boost velocity on the condensate is considered. Specifically, we observe a critical velocity for the nucleation of vortices in our system that is strongly linked to a steplike decrease in the sup...

We numerically model turbulence in a trapped atomic Bose–Einstein condensate by solving the Gross–Pitaevskii nonlinear Schroedinger equation. We find that, after an initial growth, the vortex length decays approximately as t−1 where t is time, consistent with experiments in turbulent superfluid helium, and that the velocity components obey power-law statistics, again in agreement with observati...

We present results concerning the linear (radial and non–radial) oscillations of non–rotating superfluid neutron stars in Newtonian physics. We use a simple two–fluid model to describe the superfluid neutron star, where one fluid consists of the superfluid neutrons, while the second fluid contains all the comoving constituents (protons, electrons). The two fluids are assumed to be “free” in the...

Path-integral Monte Carlo calculations of the superfluid density throughout 4He droplets doped with linear impurities are presented. After deriving a local estimator for the superfluid density distribution, we find a decreased superfluid response in the cylindrically symmetric region of the first solvation layer. The helium in this region has a superfluid transition temperature similar to that ...

Title of Dissertation: SUPERFLUIDITY IN A DEGENERATE ATOMIC FERMI GAS Nicolai Nygaard, Doctor of Philosophy, 2003 Dissertation directed by: Professor Millard H. Alexander Chemical Physics Program Dr. Charles W. Clark National Institute of Standards and Technology Dilute atomic gases have become a powerful tool for studying many-body quantum mechanics. The best example of this is the achievement...

We investigate the role of neutron star superfluidity for magnetar oscillations. Using a plane-wave analysis we estimate the effects of a neutron superfluid in the elastic crust region. We demonstrate that the superfluid imprint is likely to be more significant than the effects of the crustal magnetic field. We also consider the region immediately beneath the crust, where superfluid neutrons ar...

Abstract We investigate the excitation spectrum and momentum distribution of ionic Bose–Hubbard model by standard basis operator method. derive Green’s functions in random phase approximation Mott insulator, superfluid, charge density wave, supersolid phases. The has gapped modes gapless Goldstone superfluid show that a peak at zone corner wave close to boundary. In addition, we demonstrate can...

We use Quantum Monte Carlo to evaluate the conductivity σ of the 2–dimensional disordered boson Hubbard model at the superfluid-bose glass phase boundary. At the critical point for particle density ρ = 0.5, we find σ c = (0.45 + 0.07)σ Q , where σ Q = e 2 * /h from a finite size scaling analysis of the superfluid density. We obtain σ c = (0.47 + 0.08)σ Q from a direct calculation of the current...

We investigate the Bose-Einstein condensation (BEC, superfluidity) of particle-hole pairs in ultracold fermionic atoms with repulsive interactions and arbitrary polarization, which are trapped within optical lattices. In the strongly repulsive limit, the dynamics of particle-hole pairs can be described by a hard-core Bose-Hubbard model. The insulator-superfluid and charge-density-wave- (CDW) su...