Lorentz Invariance Violation and Generalized Uncertainty Principle

TL;DR

This paper explores how quantum gravity theories predicting minimal length and maximal momentum lead to Lorentz invariance violation, affecting particle velocities and time delays, with implications for cosmic ray and gamma-ray observations.

Contribution

It introduces a generalized uncertainty principle that modifies dispersion relations, analyzes Lorentz invariance violation effects, and compares theoretical predictions with astrophysical data.

Findings

LIV contributes to time delays consistent with some observations

OPERA neutrino anomaly data do not support LIV interpretation

Constraints on GUP parameter $eta$ from cosmic ray and gamma-ray data

Abstract

There are several theoretical indications that the quantum gravity approaches may have predictions for a minimal measurable length, and a maximal observable momentum and throughout a generalization for Heisenberg uncertainty principle. The generalized uncertainty principle (GUP) is based on a momentum-dependent modification in the standard dispersion relation which is conjectured to violate the principle of Lorentz invariance. From the resulting Hamiltonian, the velocity and time of flight of relativistic distant particles at Planck energy can be derived. A first comparison is made with recent observations for Hubble parameter in redshift-dependence in early-type galaxies. We find that LIV has two types of contributions to the time of flight delay $\Delta t$ comparable with that observations. Although the wrong OPERA measurement on faster-than-light muon neutrino anomaly, $\Delta t$, and the relative change in the speed of muon neutrino $\Delta v$ in dependence on redshift $z$ turn to be wrong, we utilize its main features to estimate $\Delta v$. Accordingly, the results could not be interpreted as LIV. A third comparison is made with the ultra high-energy cosmic rays (UHECR). It is found that an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly spacial relativity and the one assuming a perturbative departure from exact Lorentz invariance. Fixing the sensitivity factor and its energy dependence are essential inputs for a reliable confronting of our calculations to UHECR. The sensitivity factor is related to the special time of flight delay and the time structure of the signal. Furthermore, the upper and lower bounds to the parameter, $\alpha$ that characterizes the generalized uncertainly principle, have to be fixed in related physical systems such as the gamma rays bursts.