Related papers: Robust Limits on Lorentz Violation from Gamma-Ray …
In quantum theory of gravity, we expect the Lorentz Invariance Violation (LIV) and the modification of the dispersion relation between energy and momentum for photons. The effect of the energy-dependent velocity due to the modified…
Some Quantum Gravity (QG) theories allow for a violation of Lorentz invariance (LIV), manifesting as a dependence of the velocity of light in vacuum on its energy. If such a dependence exists, then photons of different energies emitted…
Due to their cosmological distances high-energy astrophysical sources allow for unprecedented tests of fundamental physics. Gamma-ray bursts (GRBs) comprise among the most sensitive laboratories for exploring the violation of the central…
Various approaches to quantum gravity suggest the possibility of violation of Lorentz symmetry at very high energies. In these cases we expect a modification at low energies of the dispersion relation of photons that contains extra powers…
Lorentz violation (LV) is predicted by some quantum gravity theories, where photon dispersion relation is modified, and the speed of light becomes energy-dependent. Consequently, it results in a tiny time delay between high energy photons…
The positive-to-negative transition of spectral lag is an uncommon feature reported in a small number of GRBs. An application of such a feature has been made to constrain the critical quantum gravity energy ($E_{\rm QG}$) of the light…
Gamma ray bursts are excellent candidates to constrain physical models which break Lorentz symmetry. We consider deformed dispersion relations which break the boost invariance and lead to an energy-dependent speed of light. In these models,…
A cornerstone of special relativity is Lorentz Invariance, the postulate that all observers measure exactly the same photon speeds independently on the photon energies. However, a hypothesized structure of spacetime may alter this…
We present an analysis of the Internal Shock Model of GRBs, where gamma-rays are produced by internal shocks within a relativistic wind. We show that observed GRB characteristics impose stringent constraints on wind and source parameters.…
Lorentz-invariance violation (LV) at energy scales approaching the Planck regime serves as a critical probe for understanding quantum gravity phenomenology. Astrophysical observations of gamma-ray bursts (GRBs) present a promising avenue…
In the gravity quantum theory, the quantization of spacetime may lead to the modification of the dispersion relation between the energy and the momentum and the Lorentz invariance violation (LIV). High energy and long-distance gamma-ray…
We discuss possible tests of the constancy of the velocity of light using distant astrophysical sources such as gamma-ray bursters (GRBs), Active Galactic Nuclei (AGNs) and pulsars. This speculative quest may be motivated by some models of…
Since Lorentz invariance plays an important role in modern physics, it is of interest to test the possible Lorentz invariance violation (LIV). The time-lag (the arrival time delay between light curves in different energy bands) of Gamma-ray…
We search for possible time lags caused by quantum gravitational (QG) effects using gamma-ray bursts (GRBs) detected by INTEGRAL. The advantage of this satellite is that we have at our disposal the energy and arrival time of every detected…
Lorentz Invariance Violation (LIV) arises in various quantum-gravity theories. As the typical energy for quantum gravity is the Planck mass, $M_{pl}$, LIV will, most likely, be manifested at very high energies that are not accessible on…
Previous researches on high-energy photon events from gamma-ray bursts~(GRBs) suggest a light speed variation $v(E)=c(1-E/E_{\mathrm{LV}})$ with $E_{\mathrm{LV}}=3.6\times10^{17}~\mathrm{ GeV}$, together with a pre-burst scenario that…
Theoretical models and experimental observations suggest that gamma-ray bursts (GRB) and high-energy neutrino bursts travelling through the interstellar space may reach the Earth at different speeds. We propose and study in details the…
It has been long conjectured that a signature of Quantum Gravity will be Lorentz Invariance Violation (LIV) that could be observed at energies much lower than the Planck scale. One possible signature of LIV is an energy-dependent speed of…
Lorentz invariance violation (LIV) can manifest itself by an energy-dependent vacuum dispersion of light, which leads to arrival-time differences of photons with different energies originating from the same astronomical source. The spectral…
Recently a series of studies on high energy gamma-ray burst~(GRB) photons suggest a light speed variation with linear energy dependence at the Lorentz violation scale of $3.6 \times 10^{17}~\mathrm{GeV}$, with subluminal propagation of high…