Lorentz Violation: Motivation and New Constraints

Abstract

We review the main theoretical motivations and observational constraints on Planck scale suppressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives.

A simple UV completion of QED in 5 dimensions

“…Astrophysical bounds, particularly coming from cosmic ray observations, generally constraint the size of the a i p 2 corrections above, pushing Λ to very high scales for a i ∼ 1 (see e.g. [15] for an overview). We have not systematically studied the bounds on Λ coming from these experiments, but considered only a specific one, which is quite likely not the most stringent one.…”

Quantum effects in warp drives

“…Indeed, it is known that non-linear dispersion relations remove Cauchy horizons and regulate the fluxes emitted by white holes [14]. Moreover, although observations constrain to ultra high energy a possible breaking of that symmetry [22], one cannot definitely exclude ultraviolet violations of the local Lorentz symmetry, which have been suggested by several investigations [23][24][25].…”

Limits on the Lorentz Invariance Violation from UHECR Astrophysics

“…Astroparticle physics has been proposed as an appropriate test environment for possible Lorentz Invariance Violation (LIV) given the large energy of the particles, the large propagation distances, the accumulation of small interaction effects and recently the precision of the measurements (Liberati & Maccione (2009) ;Stecker & Scully (2005; Amelino-Camelia et al (1998); Jacobson et al (2003); Galaverni & Sigl (2008a,b); Xu & Ma (2016); Chang et al (2016); Ellis & Mavromatos (2013); The MAGIC Collaboration (2008); Ellis et al (2006Ellis et al ( , 2008; Fairbairn et al (2014); Biteau & Williams (2015); Tavecchio & Bonnoli (2016); Rubtsov et al (2017)). …”