Related papers: Anomalous positron excess from Lorentz-violating Q…
It was recently suggested that possible small volations of Lorentz invariance could explain the existence of UHECR beyond the GZK cutoff and the observations of multi-TeV gamma-rays from Mkn 501. Our analysis of Lorentz-violating kinematics…
We investigate the propagation of a charged particle in a spatially constant but time dependent pseudoscalar background. Physically this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit…
A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemann-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential…
At finite density parity can be spontaneously broken in strong interactions with far reaching implications. In particular, a time-dependent pseudoscalar background would modify QED by adding a Chern-Simons term to the lagrangian. As a…
We consider the possibility that Lorentz violation can generate differences between the limiting velocities of light and charged matter. Such effects would lead to efficient vacuum Cherenkov radiation or rapid photon decay. The absence of…
We show that an anomalous pinch can occur in ultrarelativistic electron-electron or positron-positron beam interaction, caused by the combined interplay of collective beam motion (disruption) and strong-field quantum electrodynamics…
We reconsider an alternative theory of the QED with the photon as a massless vector Nambu-Goldstone boson and show that the underlying spontaneous Lorentz violation caused by the vector field vacuum expectation value, while being…
Lorentz Invariance Violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov…
It is by now clear that infrared sector of QED has an intriguingly complex structure. Based on earlier pioneering works on this subject, two of us recently proposed a simple modification of QED by constructing a generalization of the $U(1)$…
Recent work has shown that dispersion relations with Planck scale Lorentz violation can produce observable effects at energies many orders of magnitude below the Planck energy M. This opens a window on physics that may reveal quantum…
Lorentz violation at high energies might lead to non linear dispersion relations for the fundamental particles. We analyze observational constraints on these without assuming any a priori equality between the coefficients determining the…
Spontaneous violation of Lorentz symmetry by the vacuum condensation of an antisymmetric $2$-tensor is considered. The coset construction for nonlinear realization of spacetime symmetries is employed to build the most general low-energy…
A tiny Lorentz symmetry breaking can be mediated in Electrodynamics by means of the Chern-Simons (CS) interaction polarized along a constant CS vector. Its presence makes the vacuum optically active that has been recently estimated from…
We investigate the propagation of a charged particle in a spatially constant, but time dependent, pseudoscalar background. Physically this pseudoscalar background could be provided by a relic axion density. The background leads to an…
The observation of cosmic neutrinos up to 2 PeV is used to put bounds on the energy scale of Lorentz invariance violation through the loss of energy due to the production of $e^+e^-$ pairs in the propagation of superluminal neutrinos. A…
We point out that violation of Lorentz invariance affects the interaction of high-energy photons with the Earth's atmosphere and magnetic field. In certain parameter region this interaction becomes suppressed and the photons escape…
A status report is given of some recent theoretical and experimental investigations looking for signals of Lorentz violation in QED. Experiments with light, charged particles, and atoms have exceptional sensitivity to small shifts in energy…
From special relativity, photon annihilation process \HepProcess{{\Pgg}{\Pgg}{\to}{\Pep}{\Pem}} prevents cosmic photons with energies above a threshold to propagate a long distance in cosmic space due to their annihilation with low energy…
We study an extension of QED involving a light pseudoscalar (an axion-like particle), together with a very massive fermion which has Lorentz-violating interactions with the photon and the pseudoscalar, including a nonminimal…
The extended QED with renormalizable interactions breaking the Lorentz and CPT symmetry is considered and the phenomenological consequences of such a symmetry breaking are illuminated in view of recent discussion of large scale anisotropy…