8,201,125 research outputs found
Structure of the Isovector Dipole Resonance in Neutron-Rich Nucleus and Direct Decay from Pygmy Resonance
The structure of the isovector dipole resonance in neutron-rich calcium
isotope, , has been investigated by implementing a careful treatment
of the differences of neutron and proton radii in the continuum random phase
approximation (). The calculations have taken into account the current
estimates of the neutron skin. The estimates of the escape widths for direct
neutron decay from the pygmy dipole resonance () were shown rather wide,
implicating a strong coupling to the continuum. The width of the giant dipole
resonance () was evaluated, bringing on a detailed discussion about its
microscopic structure.Comment: 13 pages, 2 figures, RevTex
Three-party qutrit-state sharing
A three-party scheme for securely sharing an arbitrary unknown single-qutrit
state is presented. Using a general Greenberger-Horne-Zeilinger (GHZ) state as
the quantum channel among the three parties, the quantum information (i.e., the
qutrit state) from the sender can be split in such a way that the information
can be recovered if and only if both receivers collaborate. Moreover, the
generation of the scheme to multi-party case is also sketched.Comment: 7 page
A description of the ratio between electric and magnetic proton form factors by using space-like, time-like data and dispersion relations
We use the available information on the ratio between the electric and
magnetic proton form factors coming from recently published space-like data and
from the few available time-like data. We apply a dispersive procedure on these
data to evaluate the behaviour of this ratio, as a complex function, for all
values of q^2.Comment: 12 pages, 7 Encapsulated Postscript figures, uses epsfig, rotating,
exscale, amsmath, cite, latexsym, graphics, color packages, added reference
A phenomenological analysis of the longitudinal structure function at small and low
The longitudinal structure function in deep inelastic scattering is one of
the observables from which the gluon distribution can be unfolded.
Consequently, this observable can be used to constrain the QCD dynamics at
small . In this work we compare the predictions of distinct QCD models with
the recent experimental results for at small and low
obtained by the H1 collaboration. We focus mainly on the color dipole approach,
selecting those models which include saturation effects. Such models are
suitable at this kinematical region and also resum a wide class of higher twist
contributions to the observables. Therefore, we investigate the influence of
these corrections to in the present region of interest.Comment: 13 pages, 3 figures. Version to be published in Eur. Phys. J.
Ground State Properties of an Asymmetric Hubbard Model for Unbalanced Ultracold Fermionic Quantum Gases
In order to describe unbalanced ultracold fermionic quantum gases on optical
lattices in a harmonic trap, we investigate an attractive () asymmetric
() Hubbard model with a Zeeman-like magnetic
field. In view of the model's spatial inhomogeneity, we focus in this paper on
the solution at Hartree-Fock level. The Hartree-Fock Hamiltonian is
diagonalized with particular emphasis on superfluid phases. For the special
case of spin-independent hopping we analytically determine the number of
solutions of the resulting self-consistency equations and the nature of the
possible ground states at weak coupling. Numerical results for unbalanced
Fermi-mixtures are presented within the local density approximation. In
particular, we find a fascinating shell structure, involving normal and
superfluid phases. For the general case of spin-dependent hopping we calculate
the density of states and the possible superfluid phases in the ground state.
In particular, we find a new magnetized superfluid phase.Comment: 9 pages, 5 figure
Anderson localization of elementary excitations in a one dimensional Bose-Einstein condensate
We study the elementary excitations of a transversely confined Bose-Einstein
condensate in presence of a weak axial random potential. We determine the
localization length (i) in the hydrodynamical low energy regime, for a domain
of linear densities ranging from the Tonks-Girardeau to the transverse
Thomas-Fermi regime, in the case of a white noise potential and (ii) for all
the range of energies, in the ``one-dimensional mean field regime'', in the
case where the randomness is induced by a series of randomly placed point-like
impurities. We discuss our results in view of recent experiments in elongated
BEC systems.Comment: 11 pages, 6 figures. Final printed versio
A classification of entanglement in three-qubit systems
We present a classification of three-qubit states based in their three-qubit
and reduced two-qubit entanglements. For pure states these criteria can be
easily implemented, and the different types can be related with sets of
equivalence classes under Local Unitary operations. For mixed states
characterization of full tripartite entanglement is not yet solved in general;
some partial results will be presented here.Comment: Shortened version. Accepted in EPJ
Quarkonia and heavy flavors at the LHC
Perspectives for quarkonia and heavy flavors measurements in heavy ion
collisions at LHC are reviewedComment: 6 pages, Proceedings of the Hard Probes 2004 Conference, Ericeira,
Portugal, Nov 2004, replaced with revised versio
Josephson oscillation of a superfluid Fermi gas
Using the complete numerical solution of a time-dependent three-dimensional
mean-field model we study the Josephson oscillation of a superfluid Fermi gas
(SFG) at zero temperature formed in a combined axially-symmetric harmonic plus
one-dimensional periodic optical-lattice (OL) potentials after displacing the
harmonic trap along the axial OL axis. We study the dependence of Josephson
frequency on the strength of the OL potential. The Josephson frequency
decreases with increasing strength as found in the experiment of Cataliotti et
al. [Science 293 (2001) 843] for a Bose-Einstein condensate and of the
experiment of Pezze et al. [Phys. Rev. Lett. 93 (2004) 120401] for an ideal
Fermi gas. We demonstrate a breakdown of Josephson oscillation in the SFG for a
large displacement of the harmonic trap. These features of Josephson
oscillation of a SFG can be tested experimentally.Comment: 7 pages, 10 figure
Rehabilitation of hearing impaired children in India – An update
The prevalence of deafness in India is fairly significant. It is the second most common cause of disability. Approximately 63 million people (6.3%) in India suffer from significant auditory loss.1 Rehabilitation of hearing impaired children in India remains a challenging task. Early detection and intervention are the mainstay of this initiative. This article does not purport to detail the clinical aspects and surgical management of hearing handicapped children.We discuss here the resources and options available in India for the education of deaf children and the role of the Government bodies in rehabilitation. Awareness abouteducation and rehabilitation of hearing handicapped is low among the general public and even among the medical fraternity.
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