scholarly journals Probing Quantum Gravity with Imaging Atmospheric Cherenkov Telescopes

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 345
Author(s):  
Tomislav Terzić ◽  
Daniel Kerszberg ◽  
Jelena Strišković
Keyword(s):  
Quantum Gravity ◽  
Historical Development ◽  
Lorentz Invariance ◽  
High Energy ◽  
Cherenkov Telescopes ◽  
Analysis Methods ◽  
Invariance Violation ◽  
Lorentz Invariance Violation ◽  
Comparison Of The Results ◽  
Energy Dependent

High energy photons from astrophysical sources are unique probes for some predictions of candidate theories of Quantum Gravity (QG). In particular, Imaging atmospheric Cherenkov telescope (IACTs) are instruments optimised for astronomical observations in the energy range spanning from a few tens of GeV to ∼100 TeV, which makes them excellent instruments to search for effects of QG. In this article, we will review QG effects which can be tested with IACTs, most notably the Lorentz invariance violation (LIV) and its consequences. It is often represented and modelled with photon dispersion relation modified by introducing energy-dependent terms. We will describe the analysis methods employed in the different studies, allowing for careful discussion and comparison of the results obtained with IACTs for more than two decades. Loosely following historical development of the field, we will observe how the analysis methods were refined and improved over time, and analyse why some studies were more sensitive than others. Finally, we will discuss the future of the field, presenting ideas for improving the analysis sensitivity and directions in which the research could develop.

scholarly journals Modeling spectral lags in active galactic nucleus flares in the context of Lorentz invariance violation searches

2020 ◽  
Vol 633 ◽  
pp. A143 ◽  
Author(s):  
C. Perennes ◽  
H. Sol ◽  
J. Bolmont
Keyword(s):  
Lorentz Invariance ◽  
High Energy ◽  
Physical Parameters ◽  
New Era ◽  
Invariance Violation ◽  
Quantum Gravity Phenomenology ◽  
Lorentz Invariance Violation ◽  
Very High Energy ◽  
Energy Dependent ◽  
New Generation

Context. High-energy photons emitted by flaring active galactic nuclei (AGNs) have been used for many years to constrain modified dispersion relations in vacuum encountered in the context of quantum gravity phenomenology. In such studies, done in the GeV–TeV range, energy-dependent delays (spectral lags) are searched for, usually neglecting any source-intrinsic time delay. Aims. With the aim being to distinguish Lorentz invariance violation (LIV) effects from lags generated at the sources themselves, a detailed investigation into intrinsic spectral lags in flaring AGNs above 100 GeV is presented in the frame of synchrotron-self-Compton scenarios for their very-high-energy (VHE) emission. Methods. A simple model of VHE flares in blazars is proposed, allowing to explore the influence of the main physical parameters describing the emitting zones on intrinsic delays. Results. For typical conditions expected in TeV blazars, significant intrinsic lags are obtained, which can dominate over LIV effects, especially at low redshifts, and should therefore be carefully disentangled from any extrinsic lags. Moreover, two main regimes are identified with characteristic spectral lags, corresponding to long-lasting and fast particle acceleration. Conclusions. Such intrinsic spectral lags should be detected with new-generation instruments at VHE such as the Cherenkov Telescope Array which begins operation in a few years. This will provide original constraints on AGN flare models and open a new era for LIV searches in the photon sector.

scholarly journals Lorentz Violation Footprints in the Spectrum of High-Energy Cosmic Neutrinos—Deformation of the Spectrum of Superluminal Neutrinos from Electron-Positron Pair Production in Vacuum

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1419 ◽  
Author(s):  
José Manuel Carmona ◽  
José Luis Cortés ◽  
José Javier Relancio ◽  
Maykoll Anthonny Reyes
Keyword(s):  
Pair Production ◽  
Numerical Simulations ◽  
Lorentz Invariance ◽  
Lorentz Violation ◽  
High Energy ◽  
Energy Scale ◽  
Invariance Violation ◽  
Electron Positron ◽  
Lorentz Invariance Violation ◽  
Electron Positron Pair

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 model to study this effect, which allows us to understand qualitatively the results of numerical simulations, is presented.

scholarly journals Constraints on Lorentz Invariance Violation from Optical Polarimetry of Astrophysical Objects

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 596 ◽  
Author(s):  
Fabian Kislat
Keyword(s):  
Standard Model ◽  
Quantum Gravity ◽  
Linear Polarization ◽  
Lorentz Invariance ◽  
Polarization Angle ◽  
Standard Model Extension ◽  
Polarization Measurements ◽  
Invariance Violation ◽  
The Standard Model ◽  
Lorentz Invariance Violation

Theories of quantum gravity suggest that Lorentz invariance, the fundamental symmetry of the Theory of Relativity, may be broken at the Planck energy scale. While any deviation from conventional Physics must be minuscule in particular at attainable energies, this hypothesis motivates ever more sensitive tests of Lorentz symmetry. In the photon sector, astrophysical observations, in particular polarization measurements, are a very powerful tool because tiny deviations from Lorentz invariance will accumulate as photons propagate over cosmological distances. The Standard-Model Extension (SME) provides a theoretical framework in the form of an effective field theory that describes low-energy effects due to a more fundamental quantum gravity theory by adding additional terms to the Standard Model Lagrangian. These terms can be ordered by the mass dimension d of the corresponding operator and lead to a wavelength, polarization, and direction dependent phase velocity of light. Lorentz invariance violation leads to an energy-dependent change of the Stokes vector as photons propagate, which manifests itself as a rotation of the polarization angle in measurements of linear polarization. In this paper, we analyze optical polarization measurements from 63 Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRBs) to search for Lorentz violating signals. We use both spectropolarimetric measurements, which directly constrain the change of linear polarization angle, as well as broadband spectrally integrated measurements. In the latter, Lorentz invariance violation manifests itself by reducing the observed net polarization fraction. Any observation of non-vanishing linear polarization thus leads to constraints on the magnitude of Lorentz violating effects. We derive the first set limits on each of the 10 individual birefringent coefficients of the minimal SME with d = 4 , with 95% confidence limits on the order of 10−34 on the dimensionless coefficients.

scholarly journals HIGH ENERGY ASTROPHYSICS TESTS OF LORENTZ INVARIANCE VIOLATION

2005 ◽  
Vol 20 (14) ◽  
pp. 3139-3142 ◽  
Author(s):  
F. W. STECKER
Keyword(s):  
Lorentz Invariance ◽  
High Energy ◽  
Ultrahigh Energy ◽  
Large Extra Dimension ◽  
Bl Lac Objects ◽  
Invariance Violation ◽  
Electron Positron ◽  
Lorentz Invariance Violation ◽  
Emission Models ◽  
Flux Level

Observations of the multi-TeV spectra of the Mkn 501 and other nearby BL Lac objects exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with IR photons having a flux level as determined by various astronomical observations. After correcting for such intergalactic absorption, these spectra can be explained within the framework of synchrotron self-Compton emission models. Stecker and Glashow have shown that the existence of this annihilation via electron-positron pair production puts strong constraints on Lorentz invariance violaition. Such constraints have important implications for some quantum gravity and large extra dimension models. A much smaller amount of Lorentz invariance violation has potential implications for understanding the spectra of ultrahigh energy cosmic rays.

scholarly journals Lorentz Invariance Violation Tests in Astroparticle Physics

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1232
Author(s):  
Humberto Martínez-Huerta ◽  
Rodrigo Guedes Lang ◽  
Vitor de Souza
Keyword(s):  
Lorentz Invariance ◽  
Time Lag ◽  
Astroparticle Physics ◽  
Production Threshold ◽  
Air Shower ◽  
Photon Decay ◽  
Invariance Violation ◽  
Lorentz Invariance Violation ◽  
Photon Splitting ◽  
Energy Dependent

In this review, we present the latest exclusion limits obtained from astroparticles on Lorentz Invariance Violation (LIV) in the photon sector. We discuss the techniques known as energy-dependent time delay or time lag, subluminal pair production threshold shift, suppression of air shower formation, superluminal photon decay, and superluminal photon splitting. Perspectives for future results on LIV with the next generation of experiments are also addressed.

scholarly journals HIGH ENERGY NEUTRINO OSCILLATION AT THE PRESENCE OF THE LORENTZ INVARIANCE VIOLATION

2012 ◽  
Vol 27 (19) ◽  
pp. 1250104 ◽  
Author(s):  
IMAN MOTIE ◽  
SHE-SHENG XUE
Keyword(s):  
Neutrino Oscillation ◽  
Lorentz Invariance ◽  
Planck Scale ◽  
High Energy ◽  
Oscillation Pattern ◽  
High Energies ◽  
Invariance Violation ◽  
Lorentz Invariance Violation ◽  
Very High Energy ◽  
Very High

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 paper, we study the neutrino oscillation pattern due to the Lorentz invariance violation (LIV), and compare it with the normal neutrino oscillation pattern due to neutrino masses. We find that at very high energies, neutrino oscillation pattern is very different from the normal one. This could provide an possibility to study the Lorentz invariance violation by measuring the oscillation pattern of very high energy neutrinos from a cosmological distance.

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