17 research outputs found
Speed dependent polarization correlations in QED and entanglement
Exact computations of polarizations correlations probabilities are carried
out in QED, to the leading order, for initially polarized as well as
unpolarized particles. Quite generally they are found to be speed dependent and
are in clear violation of Bells inequality of Local Hidden Variables (LHV)
theories. This dynamical analysis shows how speed dependent entangled states
are generated. These computations, based on QED are expected to lead to new
experiments on polarization correlations monitoring speed in the light of Bells
theorem. The paper provides a full QED treatment of the dynamics of
entanglement.Comment: LaTeX, 14 pages, 2 figures, Corrected typo
Spin correlations in elastic scattering in QED
Spin correlations are carefully investigated in elastic
scattering in QED, for initially \textit{polarized} as well as
\textit{unpolarized} particles, with emphasis placed on energy or speed of the
underlying particles involved in the process. An explicit expression is derived
for the corresponding transition probabilities in closed form to the leading
order. These expressions are unlike the ones obtained from simply combining
spins of the relevant particles which are of kinematic nature. It is remarkable
that these explicit results obtained from quantum field theory show a clear
violation of Bell's inequality at \textit{all} energies in support of quantum
theory in the relativistic regime. We hope that our explicit expression
obtained will lead to experiments in the manner described in the bulk of this
paper by monitoring speed.Comment: 9 pages, 2 figure
Dynamics of Dirac-Born-Infeld dark energy interacting with dark matter
We study the dynamics of Dirac-Born-Infeld (DBI) dark energy interacting with dark matter. The DBI dark energy model considered here has a scalar field with a nonstandard kinetic energy term, and has potential and brane tension that are power-law functions. The new feature considered here is an interaction between the DBI dark energy and dark matter through a phenomenological interaction between the DBI scalar field and the dark matter fluid. We analyze two different types of interactions between the DBI scalar field and the dark matter fluid. In particular we study the phase-space diagrams of and look for critical points of the phase space that are both stable and lead to accelerated, late-time expansion. In general we find that the interaction between the two dark components does not appear to give rise to late-time accelerated expansion. However, the interaction can make the critical points in the phase space of the system stable. Whether such stabilization occurs or not depends on the form of the interaction between the two dark components. © 2012 American Physical Society
Spin Correlations in Pair Creation by Two-Photons and Entanglement in QED
Spin correlations of pair productions of two colliding photons
are investigated and explicit expressions for their corresponding probabilities
are derived and found to be \textit{energy} (speed) dependent, for initially
\textit{linearly} and \textit{circularly polarized} photons, different from
those obtained by simply combining the spins of the relevant particles, for
initially \textit{polarized} photons. These expressions also depend on the
angles of spin of (and/or of ), for initially {\it linearly
polarized} photons, but not for {\it circularly polarized} photons, as a
function of the energy. It is remarkable that these explicit results obtained
from quantum field theory show a clear violation of Bell's inequality of Local
Hidden Variables theories at all {\it energies} beyond that of the threshold
one for particle production, in support of quantum field theory in the
relativistic regime. We hope that our explicit expression will lead to
experiments, of the type described in the bulk of this paper, which can monitor
energy (and speed) in polarization correlation experiments.Comment: 12 pages, 4 figure
A two measure model of dark energy and dark matter
In this work we construct a unified model of dark energy and dark matter.
This is done with the following three elements: a gravitating scalar field, phi
with a non-conventional kinetic term, as in the string theory tachyon; an
arbitrary potential, V(phi); two measures -- a metric measure (sqrt{-g}) and a
non-metric measure (Phi). The model has two interesting features: (i) For
potentials which are unstable and would give rise to tachyonic scalar field,
this model can stabilize the scalar field. (ii) The form of the dark energy and
dark matter that results from this model is fairly insensitive to the exact
form of the scalar field potential.Comment: 8 pages,no figures, revtex, typos corrected to match published
versio
Polarization Correlations in Pair Production from Charged and Neutral Strings
Polarization correlations of pair productions from charged and
neutral Nambu strings are investigated, via photon and graviton emissions,
respectively and explicit expressions for their corresponding probabilities are
derived and found to be \textit{speed} dependent. The strings are taken to be
circularly oscillating closed strings, as perhaps the simplest solution of the
Nambu action. In the extreme relativistic case, these probabilities coincide,
but, in general, are different, and such inquiries, in principle, indicate
whether the string is charged or uncharged. It is remarkable that these
dynamical relativistic quantum field theory calculations lead to a clear
violation of Local Hidden Variables theories.Comment: 6 pages, no figure, LaTeX with ws-mpla.cl