6,651 research outputs found
BCS-BEC crossover in a gas of Fermi atoms with a p-wave Feshbach resonance
We investigate unconventional superfluidity in a gas of Fermi atoms with an
anisotropic p-wave Feshbach resonance. Including the p-wave Feshbach resonance
as well as the associated three kinds of quasi-molecules with finite orbital
angular momenta , we calculate the transition temperature of the
superfluid phase. As one passes through the p-wave Feshbach resonance, we find
the usual BCS-BEC crossover phenomenon. The p-wave BCS state continuously
changes into the BEC of bound molecules with L=1. Our calculation includes the
effect of fluctuations associated with Cooper-pairs and molecules which are not
Bose-condensed.Comment: 9 pages, 3 figures, 1 tabl
Surface-enhanced pair transfer in quadrupole states of neutron-rich Sn isotopes
We investigate the neutron pair transfer modes associated with the low-lying
quadrupole states in neutron-rich Sn isotopes by means of the quasiparticle
random phase approximation based on the Skyrme-Hartree-Fock-Bogoliubov mean
field model. The transition strength of the quadrupole pair-addition mode
feeding the state is enhanced in the Sn isotopes with . The
transition density of the pair-addition mode has a large spatial extension in
the exterior of nucleus, reaching far to fm. The quadrupole
pair-addition mode reflects sensitively a possible increase of the effective
pairing interaction strength in the surface and exterior regions of
neutron-rich nuclei.Comment: 14 page
On Koopman-von Neumann Waves II
In this paper we continue the study, started in [1], of the operatorial
formulation of classical mechanics given by Koopman and von Neumann (KvN) in
the Thirties. In particular we show that the introduction of the KvN Hilbert
space of complex and square integrable "wave functions" requires an enlargement
of the set of the observables of ordinary classical mechanics. The possible
role and the meaning of these extra observables is briefly indicated in this
work. We also analyze the similarities and differences between non selective
measurements and two-slit experiments in classical and quantum mechanics.Comment: 18+1 pages, 1 figure, misprints fixe
Reply to "Comment on 'Topological stability of the half-vortices in spinor exciton-polariton condensates'"
In a recent work [H. Flayac, I.A. Shelykh, D.D. Solnyshkov and G. Malpuech,
Phys. Rev. B 81, 045318 (2010)], we have analyzed the effect of the TE-TM
splitting on the stability of the exciton-polariton vortex states. We
considered classical vortex solutions having cylindrical symmetry and we found
that the so-called half-vortex states [Yu. G. Rubo, Phys. Rev. Lett. 99, 106401
(2007)] are not solutions of the stationary Gross-Pitaevskii equation. In their
Comment [M. Toledo Solano, Yu.G. Rubo, Phys. Rev. B 82, 127301 (2010)], M.
Toledo Solano and Yuri G. Rubo claim that this conclusion is misleading and
pretend to demonstrate the existence of static half-vortices in an
exciton-polariton condensate in the presence of TE-TM splitting. In this reply
we explain why this assertion is not demonstrated satisfactorily.Comment: 3 Pages, no figur
Rotationally-invariant slave-bosons for Strongly Correlated Superconductors
We extend the rotationally invariant formulation of the slave-boson method to
superconducting states. This generalization, building on the recent work by
Lechermann et al. [Phys. Rev. B {\bf 76}, 155102 (2007)], allows to study
superconductivity in strongly correlated systems. We apply the formalism to a
specific case of strongly correlated superconductivity, as that found in a
multi-orbital Hubbard model for alkali-doped fullerides, where the
superconducting pairing has phonic origin, yet it has been shown to be favored
by strong correlation owing to the symmetry of the interaction. The method
allows to treat on the same footing the strong correlation effects and the
interorbital interactions driving superconductivity, and to capture the physics
of strongly correlated superconductivity, in which the proximity to a Mott
transition favors the superconducting phenomenon.Comment: 18 pages, 7 figure
Calculation of NMR Properties of Solitons in Superfluid 3He-A
Superfluid 3He-A has domain-wall-like structures, which are called solitons.
We calculate numerically the structure of a splay soliton. We study the effect
of solitons on the nuclear-magnetic-resonance spectrum by calculating the
frequency shifts and the amplitudes of the soliton peaks for both longitudinal
and transverse oscillations of magnetization. The effect of dissipation caused
by normal-superfluid conversion and spin diffusion is calculated. The
calculations are in good agreement with experiments, except a problem in the
transverse resonance frequency of the splay soliton or in magnetic-field
dependence of reduced resonance frequencies.Comment: 15 pages, 10 figures, updated to the published versio
BCS - BEC crossover at T=0: A Dynamical Mean Field Theory Approach
We study the T=0 crossover from the BCS superconductivity to Bose-Einstein
condensation in the attractive Hubbard Model within dynamical mean field
theory(DMFT) in order to examine the validity of Hartree-Fock-Bogoliubov (HFB)
mean field theory, usually used to describe this crossover, and to explore
physics beyond it. Quantum fluctuations are incorporated using iterated
perturbation theory as the DMFT impurity solver. We find that these
fluctuations lead to large quantitative effects in the intermediate coupling
regime leading to a reduction of both the superconducting order parameter and
the energy gap relative to the HFB results. A qualitative change is found in
the single-electron spectral function, which now shows incoherent spectral
weight for energies larger than three times the gap, in addition to the usual
Bogoliubov quasiparticle peaks.Comment: 11 pages,12 figures, Published versio
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