Phase-space deformation of a dipolar Fermi gas in free expansion
(Submitted on 10 Jul 2009)
Abstract: We theoretically investigate a
polarized dipolar Fermi gas in free expansion. The dipolar-dipolar
inter-particle interaction deforms phase-space distribution in trap
and also in the expansion. We exactly predict the minimal
quadrupole deformation in the expansion for the high-temperature
Maxwell-Boltzmann (MB) and zero-temperature Thomas-Fermi (TF) gases
in the Hartree-Fock and Landau-Vlasov approaches by developing a
new deformation ansatz. In conclusion, we reveal a scaling law
associated with the Liouville's theorem in the long-time behaviors
of the MB and TF gases and also provide a proper theoretical
approach to develop
Density profiles of an interacting three-component normal Fermi gas
in a harmonic trap
(Submitted on 10 Jul 2009)
Abstract: We use Thomas-Fermi
approximation to investigate the density variations of an
interacting three-component normal Fermi gas in a harmonic trap. We
consider both attractive and repulsive interactions between
different pairs of fermions and study the effect of population
imbalance on densities. We find that the density profiles
significantly deviate from those of non-interacting profiles and
extremely sensitive to the interactions and population imbalance.
Unlike two-component Fermi systems, we find density imbalance in
the trap even for balanced populations. For some range of
parameters, one component completely repels from the trap center
giving rise a donut shape density profile.
Lifshitz Point in Resonantly Interacting $^6Li$-$^{40}K$ Mixtures
(Submitted on 10 Jul 2009)
Abstract: We consider a strongly
interacting ${}^{6}$Li-${}^{40}$K mixture, which is imbalanced both
in the masses and the densities of the two fermionic species. At
present, it is the experimentalist's favorite for reaching the
superfluid regime. We construct an effective thermodynamic
potential that leads to excellent agreement with Monte Carlo
results for the normal state. We use it to determine the universal
phase diagram of the mixture in the unitarity limit, where we find,
in contrast to the mass-balanced case, the presence of a Lifshitz
point. This
Mesoscopic cavity-QED: the physics behind off-resonant cavity
excitation by a single quantum dot
Luttinger liquid of trimers in Fermi gases with unequal masses
(Submitted on 9 Jul 2009)
Abstract: We investigate one dimensional
attractive Fermi gases in spin-dependent optical lattices. Starting
from the asymmetric Hubbard model, we show that three-body bound
states - ``trimers'' - exist as soon as the two tunneling rates are
different. We calculate the binding energy and the effective mass
of a single trimer. We then show numerically that for finite
commensurate densities $n_\uparrow=n_\downarrow/2$ an energy gap
appears, implying that the gas is a one-component Luttinger liquid
of trimers with suppressed superfluid ordering. The
boun
Observation of stable 3-vortex/anti-vortex clusters in a superfluid
Bose-Einstein condensate
Two-dimensional boson-fermion mixtures
(Submitted on 6 Jul 2009)
Abstract: Using mean-field theory, we
study the equilibrium properties of boson-fermion mixtures confined
in a harmonic pancake-shaped trap at zero temperature. When the
modulus of the s-wave scattering lengths are comparable to the
mixture thickness, two-dimensional scattering events introduce a
logarithmic dependence on density in the coupling constants,
greatly modifying the density profiles themselves. We show that for
the case of a negative boson-fermion three-dimensional s-wave
scattering leng
Strong parity effect of particle number in the interference fringes
of Bose-Einstein condensates released from a double-well potential
(Submitted on 7 Jul 2009)
Abstract: We study the parity effect of
the particle number in the interference fringes of a Bose-Einstein
condensate released from a double-well potential. For a coherently
splitting condensate in the double-well potential, with a decoupled
two-mode Bose-Hubbard model, there is well-known phase diffusion
because of interatomic interactions. After a specific holding time
of the double-well potential, the phase diffusion will make the
interference patterns in the density distribution depend strongly
on the parity of the total particle number by further overlapping
two condensates. This p
Probing the quantum ground state of a spin-1 Bose-Einstein
condensate with cavity transmission spectra
(Submitted on 7 Jul 2009)
Abstract: We propose to probe the quantum
ground state of a spin-1 Bose-Einstein condensate with the
transmission spectra of an optical cavity. By choosing a circularly
polarized cavity mode with an appropriate frequency, we can realize
coupling between the cavity mode and the magnetization of the
condensate. The cavity transmission spectra then contain
information of
Generalized nonpolynomial Schrodinger equations for matter waves
under anisotropic transverse confinement
(Submitted on 7 Jul 2009)
Abstract: Starting from the
three-dimensional Gross-Pitaevskii equation we derive a 1D
generalized nonpolynomial Schrodinger equation, which describes the
dynamics of Bose-Einstein condensates under the action of a generic
potential in the longitudinal axial direction and of an anisotropic
harmonic potential in the transverse radial direction. This
equation reduces to the familiar 1D nonpolynomial Schrodinger
equation [Phys. Rev. A 65, 043614 (2002)] in the case of isotropic
transverse harmonic confinement. In addition, we show that if the
longitudinal potential models a periodic optical lattice the 3D GPE
can be mapped into a 1D generalized discrete nonpolynomial
Schrodinger equation.