517 research outputs found
Explicit expression for the photon number emission in synchrotron radiation
An explicit and remarkably simple one-dimensional integral expression is
derived for the mean number of photons emitted per revolution in
synchrotron radiation. The familiar high-energy expression
$5\pi\alpha/\sqrt{3(1-\beta^2)}$, printed repeatedly in the literature, is
found to be inaccurate and only truly asymptotic with relative errors of 160%,
82% for $\beta=0.8$, 0.9, respectively. A new improved high-energy expression
for is given.Comment: LaTeX, 3 pages, no figur
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
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
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
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
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