Lorentz breaking Effective Field Theory and observational tests

TL;DR

This paper reviews the effective field theory approach to Lorentz invariance violations, discusses observational constraints, and explores implications for high-energy cosmic rays and analogue gravity models.

Contribution

It provides a comprehensive overview of Lorentz breaking effective field theories, summarizes current observational constraints, and discusses implications for quantum gravity phenomenology.

Findings

Current observations place strong constraints on Lorentz violations.

Analogue gravity models can test Lorentz breaking phenomenology.

Uncertainty in cosmic ray composition affects constraints on Lorentz violations.

Abstract

Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lorentz violations.