6,234 research outputs found
Character of Locally Inequivalent Classes of States and Entropy of Entanglement
In this letter we have established the physical character of pure bipartite
states with the same amount of entanglement in the same Schmidt rank that
either they are local unitarily connected or they are incomparable. There exist
infinite number of deterministically locally inequivalent classes of pure
bipartite states in the same Schmidt rank (starting from three) having same
amount of entanglement. Further, if there exists incomparable states with same
entanglement in higher Schmidt ranks (greater than three), then they should
differ in at least three Schmidt coefficients.Comment: 4 pages, revtex4, no figure, accepted in Physical Review A (rapid
communications
Energy-momentum for a charged nonsingular black hole solution with a nonlinear mass function
The energy-momentum of a new four-dimensional, charged, spherically symmetric
and nonsingular black hole solution constructed in the context of general
relativity coupled to a theory of nonlinear electrodynamics is investigated,
whereby the nonlinear mass function is inspired by the probability density
function of the continuous logistic distribution. The energy and momentum
distributions are calculated by use of the Einstein, Landau-Lifshitz, Weinberg
and M{\o}ller energy-momentum complexes. In all these prescriptions it is found
that the energy distribution depends on the mass and the charge of the
black hole, an additional parameter coming from the gravitational
background considered, and on the radial coordinate . Further, the
Landau-Lifshitz and Weinberg prescriptions yield the same result for the
energy, while in all the aforesaid prescriptions all the momenta vanish. We
also focus on the study of the limiting behavior of the energy for different
values of the radial coordinate, the parameter , and the charge .
Finally, it is pointed out that for and all the
energy-momentum complexes yield the same expression for the energy distribution
as in the case of the Schwarzschild black hole solution.Comment: 20 pages, 4 figures, two of the figures changed, Discussion modified
accordingly, present version accepted for publication in AHE
Conditions for entanglement transformation between a class of multipartite pure states with generalized Schmidt decompositions
In this note we generalize Nielsen's marjoization criterion for the
convertibility of bipartite pure states [Phys. Rev. Lett \textbf{83},
436(1999)] to a special class of multipartite pure states which have
generalized Schmidt decompositions.Comment: 3 pages (Revetex 4), no figures. A brief note on entanglement
transformation. Comments are welcom
Dynamical Mean Field Theory of Double Perovskite Ferrimagnets
The dynamical mean field method is used to analyze the magnetic transition
temperature and optical conductivity of a model for the ferrimagnetic double
perovskites such as . The calculated transition temperatures and
optical conductivities are found to depend sensitively on the band structure.
For parameters consistent with local spin density approximation band
calculations, the computed transition temperatures are lower than observed, and
in particular decrease dramatically as band filling is increased, in
contradiction to experiment. Band parameters which would increase the
transition temperature are identified.Comment: Supercedes cond-mat/000628 (PRB64 024424/1-4 (2001
Self Replication and Signalling
It is known that if one could clone an arbitrary quantum state one could send
signal faster than the speed of light. However it remains interesting to see
that if one can perfectly self replicate an arbitrary quantum state, does it
violate the no signalling principle? Here we see that perfect self replication
would also lead to superluminal signalling.Comment: Modified version of quant-ph/0510221, Accepted in International
Journal of Theoretical Physic
Theory of Transition Temperature of Magnetic Double Perovskites
We formulate a theory of double perovskite coumpounds such as SrFeReO
and SrFeMoO which have attracted recent attention for their possible
uses as spin valves and sources of spin polarized electrons. We solve the
theory in the dynamical mean field approximation to find the magnetic
transition temperature . We find that is determined by a subtle
interplay between carrier density and the Fe-Mo/Re site energy difference, and
that the non-Fe same-sublattice hopping acts to reduce . Our results
suggest that presently existing materials do not optimize
Inseparability of Quantum Parameters
In this work, we show that 'splitting of quantum information' [6] is an
impossible task from three different but consistent principles of unitarity of
Quantum Mechanics, no-signalling condition and non increase of entanglement
under Local Operation and Classical Communication.Comment: 9 pages, Presented in Quantum Computing Back Action in IIT Kanpur
(2006). Accepted in International Journal of Theoretical Physic
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