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We first comment on the search for a deviation from the linear photon dispersion relation, in particular based on cosmic photons from Gamma Ray Bursts. Then we consider the non-commutative space as a theoretical concept that could lead to…

High Energy Physics - Phenomenology · Physics 2011-08-25 Wolfgang Bietenholz

A space-dependent mean for cosmological perturbations negates the ansatz of statistical homogeneity and isotropy, and hence ergodicity. In this work, we construct such a primordial mean of scalar perturbations from an alternative quantum…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 H. V. Ragavendra , Dipayan Mukherjee , Shiv K. Sethi

Cosmic Birefringence (CB) is the in-vacuo rotation of the linear polarization direction of photons during propagation, caused by parity-violating extensions of Maxwell electromagnetism. We build low resolution CB angle maps using Planck…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-30 Marco Bortolami , Matteo Billi , Alessandro Gruppuso , Paolo Natoli , Luca Pagano

It is well known that direct observation of interference and diffraction pattern in the intensity distribution requires a spatially coherent source. Optical waves emitted from portions beyond the coherence area possess statistically…

Optics · Physics 2009-11-13 Su-Heng Zhang , Lu Gao , Jun Xiong , Li-Juan Feng , De-Zhong Cao , Kaige Wang

In this paper, we calculate the spectrum of scalar field fluctuations in a bouncing, asymptotically flat Universe, and investigate the dependence of the result on changes in the physics on length scales shorter than the Planck length which…

High Energy Physics - Theory · Physics 2009-11-07 Robert H Brandenberger , Sergio E. Joras , Jerome Martin

Effective pseudoscalar-photon interaction(s) would induce a rotation of linear polarization of electromagnetic wave propagating with cosmological distance in various cosmological models. Pseudoscalar-photon interaction is proportional to…

General Relativity and Quantum Cosmology · Physics 2009-10-23 Wei-Tou Ni

Recently some hidden inconsistencies in high energy physics and cosmology have been articulated by several scholars. If we follow the usual description we get an unacceptably high cosmological constant as was noticed by Weinberg and others…

General Physics · Physics 2024-03-13 B. G. Sidharth

It has recently been suggested that Planck scale physics may effect the evolution of cosmological fluctuations in the early stages of cosmological inflation in a non-trivial way, leading to an excited state for modes whose wavelength is…

High Energy Physics - Theory · Physics 2009-11-10 Robert H. Brandenberger , Jerome Martin

Spin is a fundamental degree of freedom, whose existence was proven by Dirac for an electron by imposing the relativity to quantum mechanics, leading to the triumph to derive the Dirac equation. Spin of a photon should be linked to…

Optics · Physics 2024-07-23 Shinichi Saito

If the fine structure constant $\alpha =e^2/(\hbar c)$ were to change, then a number of interpretations would be possible, attributing this change either to variations in the electron charge, the dielectric constant of the vacuum, the speed…

Astrophysics · Physics 2009-10-31 John D. Barrow , Joao Magueijo

Photonic crystals with a two-dimensional triangular lattice have a conical singularity in the spectrum. Close to this so-called Dirac point, Maxwell's equations reduce to the Dirac equation for an ultrarelativistic spin-1/2 particle. Here…

Mesoscale and Nanoscale Physics · Physics 2009-01-21 R. A. Sepkhanov , A. Ossipov , C. W. J. Beenakker

The propagation of photons, electrons and positrons at ultra-high energies above 10^{19} eV can be changed considerably if the dispersion relations of these particles are modified by terms suppressed by powers of the Planck scale. We…

Astrophysics · Physics 2009-09-29 Matteo Galaverni , Guenter Sigl

Environmental decoherence occurs when a quantum system interacts with its surroundings, progressively reducing quantum interference and coherence, complicating the preservation of critical quantum properties over time, especially during…

Quantum Physics · Physics 2025-12-18 Naeem Akhtar , Jia-Xin Peng , Tan Hailin , Xiaosen Yang , Dong Wang

The quasiregular singularities (horizons) that form in the collision of cross polarized electromagnetic waves are, as in the linear polarized case unstable. The validity of the Helliwell-Konkowski stability conjecture is tested for a number…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ozay Gurtug , Mustafa Halilsoy

The recent Planck Legacy 2018 release has confirmed the presence of an enhanced lensing amplitude in CMB power spectra compared to that predicted in the standard $\Lambda$CDM model. A closed universe can provide a physical explanation for…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-07 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk

We discuss possible violations of Poincare's relativity principle at energy scales close to Planck scale and point out the potentialities of high-energy cosmic-ray physics to uncover these new phenomena.

General Physics · Physics 2007-05-23 Luis Gonzalez-Mestres

We propose an experiment to test the influence of Lorentz contraction on the interference pattern of a beam of electrons. The electron beam is split and recombined by two pairs of bi-chromatic laser pulses, using a variation of the…

Classical Physics · Physics 2014-06-05 Karl-Peter Marzlin , Thomas Lee

Photonic crystals are periodic structures which prevent light propagation along one or more directions in certain frequency intervals. Their band spectrum is usually analyzed using Floquet-Bloch decomposition. This spectrum is located on…

Einstein's theory of general relativity, which contains a universal value of the Planck mass, has been so far successfully invoked to explain gravitational dynamics from sub-millimeter scales to the scale of the cosmological horizon.…

Astrophysics · Physics 2009-11-13 Georg Robbers , Niayesh Afshordi , Michael Doran

The classical Friedmann-Lema\^itre equations are solved using a corrected version of Planck's radiation law. The function curves of the scale parameter a(t) and the variations with temperature a(T) and t(T) are given. It is shown that a…

General Relativity and Quantum Cosmology · Physics 2014-10-08 Rainer Collier
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