517 research outputs found

    Explicit expression for the photon number emission in synchrotron radiation

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    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 e+e−e^{+}e^{-} Pair Creation by Two-Photons and Entanglement in QED

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    Spin correlations of e+e−e^{+}e^{-} 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 e+e^{+} (and/or of e−e^{-}), 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

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    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

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    Polarization correlations of e+e−e^{+}e^{-} 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 e+e−e^{+}e^{-} scattering in QED

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    Spin correlations are carefully investigated in elastic e+e−e^{+}e^{-} 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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