Related papers: Unitarity, ghosts and nonminimal terms in Lorentz …
We have investigated the detailed structure of $l$-plane singularities of scattering amplitude saturating the Froissart bound. A self-consistent analysis of these singularities provides us secondary terms in the Froissart bound. These…
We review some of the recent results which can be useful for better understanding of the problem of stability of vacuum and in general classical solutions in higher derivative quantum gravity. The fourth derivative terms in the purely…
We explicitly show that general local higher-derivative theories with only complex conjugate ghosts and normal real particles are unitary at any perturbative order in the loop expansion. The proof presented here relies on integrating the…
It is of general agreement that a quantum gravity theory will most probably mean a breakdown of the standard structure of space-time at the Planck scale. This has motivated the study of Planck-scale Lorentz Invariance Violating (LIV)…
This talk summarizes some theoretical features and experimental implications of a general Lorentz-violating extension of the minimal SU(3) x SU(2) x U(1) standard model that allows for both CPT-even and CPT-odd effects. The theory would…
Effective field theories which describe the coupling between gravity and matter fields have recently been extended to include terms with operators of non-minimal mass dimension. These terms preserve the usual gauge symmetries but may…
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…
We investigate the effect of electron-phonon interactions on the coherence properties of single photons emitted from a semiconductor cavity QED system, i.e. a quantum dot embedded in an optical cavity. The degree of indistinguishability,…
This paper explores the annihilation process of an electron-positron pair into a heavier lepton-antilepton pair, taking into account the presence of an external classical magnetic field. Additionally, it investigates corrections arising…
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…
The observed clustering of ultra-high energy cosmic rays suggests the existence of a neutral component. The models with violation of Lorentz invariance may explain this component by neutrons becoming stable above some threshold energy E_0.…
Neutrino flavour oscillations are analyzed in a model in which particles experience an effective Schwarzschild geometry modified by maximal acceleration corrections. These imply a quantum violation of the equivalence principle. The…
We report symmetry-breaking and restoring bifurcations of solitons in a fractional Schr\"{o}dinger equation with the cubic or cubic-quintic (CQ) nonlinearity and a parity-time (PT)-symmetric potential, which may be realized in optical…
We discuss positronium decays with emphasis on tests of fundamental symmetries and the constraints from measurements of other precision observables involving electrons and photons.
The violation of Lorentz symmetry can arise in a variety of approaches to fundamental physics. For the description of the associated low-energy effects, a dynamical framework known as the Standard-Model Extension has been developed. This…
Peierls distortion and quantum solitons are two hallmarks of 1-dimensional condensed-matter systems. Here we propose a quantum model for a one-dimensional system of non-linearly interacting electrons and phonons, where the phonons are…
This talk discusses the sensitivity of electron-positron and proton-antiproton Penning-trap experiments to CPT- and Lorentz-violating effects in the context of an extension of the minimal standard model and quantum electrodynamics.
Due to quantum gravity fluctuations at the Planck scale, the space-time manifold is no longer continuous, but discretized. As a result the Lorentz symmetry is broken at very high energies. In this article, we study the neutrino oscillation…
We reconsider the Standard Model interactions of ultra-high energy neutrinos with matter. The next to leading order QCD corrections are presented for charged-current and neutral-current processes. Contrary to popular expectations, these…
Unitarity corrections to the BFKL description of high energy hard scattering are viewed in large $N_c$ QCD in light-cone quantization. In a center of mass frame unitarity corrections to high energy hard scattering are manifestly…