1,189,219 research outputs found
Entanglement sudden death in qubit-qutrit systems
We demonstrate the existence of entanglement sudden death (ESD), the complete
loss of entanglement in finite time, in qubit-qutrit systems. In particular,
ESD is shown to occur in such systems initially prepared in a one-parameter
class of entangled mixed states and then subjected to local dephasing noise.
Together with previous results, this proves the existence of ESD for some
states in all quantum systems for which rigorously defined mixed-state
entanglement measures have been identified. We conjecture that ESD exists in
all quantum systems prepared in appropriate bipartite states.Comment: 10 pages. To appear in Physics Letters
Influence of Cooper pairing on the inelastic processes in a gas of Fermi atoms
Correlation properties in ultracold Fermi gas with negative scattering length
and its impact on the three-body recombination is analyzed. We find that Cooper
pairing enhances the recombination rate in contrast to the decrease of this
rate accompanying Bose-Einstein condensation in a Bose gas. This trend is
characteristic for all interval of temperatures T<Tc
Dual versions of N=2 supergravity and spontaneous supersymmetry breaking
In this paper, using a model of N=2 supergravity - vector multiplets
interaction with the scalar field geometry as an
example, we show that even when the geometry is fixed one can have a whole
family of the Lagrangians that differ by the vector field duality
transformations. As a byproduct, for this geometry we have constructed a model
of (m-1) vector multiplets interacting with the hidden sector admitting
spontaneous supersymmetry breaking with two arbitrary scales and without a
cosmological term.Comment: 10 pages, LaTeX, IHEP preprint 94-9
General covariance violation and the gravitational dark matter. II. Vector graviton
The (four componenet) vector graviton contained in metric, the scalar
component incorporated, is attributed to the violation of the general
covariance to the residual isoharmonic one. In addition to the previously
studied (singlet) scalar graviton, the vector graviton may constitute one more
fraction of the gravitational dark matter. The gravity interactions of the
vector graviton, as well as its impact on the continuous medium are studied.Comment: 10 page
On Wilson Criterion
U(1) gauge theory with the Villain action on a cubic lattice approximation of
three- and four-dimensional torus is considered. The naturally chosen
correlation functions converge to the correlation functions of the R-gauge
electrodynamics on three- and four-dimensional torus as the lattice spacing
approaches zero only for the special scaling. This special scaling depends on a
choice of a correlation function system. Another scalings give the degenerate
continuum limits. The Wilson criterion for the confinement is ambiguous. The
asymptotics of the smeared Wilson loop integral for the large loop perimeters
is defined by the density of the loop smearing over a torus which is
transversal to the loop plane. When the initial torus radius tends to infinity
the correlation functions converge to the correlation functions of the R-gauge
Euclidean electrodynamics.Comment: latex, 6 page
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