Spontaneous Breaking of Lorentz Invariance

Abstract

We describe how a stable effective theory in which particles of the same fermion number attract may spontaneously break Lorentz invariance by giving non-zero fermion number density to the vacuum (and therefore dynamically generating a chemical potential term). This mecanism yields a finite vacuum expectation value $<\bar{\psi }{\gamma }^{\mu }\psi >$ which we consider in the context of proposed models that require such a breaking of Lorentz invariance in order to yield composite degrees of freedom that act approximately like gauge bosons. We also make general remarks about how the background source provided by $<\bar{\psi }{\gamma }^{\mu }\psi >$ could relate to work on signals of Lorentz violation in electrodynamics.

revtex4, 11 pages, 5 figures; v2:references added; v3:more references added, typos fixed, some points in sect. IV clarified; v4:even more references added, discussion in sect. V extended; v5:replaced to match published version (minor corrections of form)

Cited by in corpus (1)

• Probing Physics in the Standard Model and Beyond with Electroweak Baryogenesis and Effective Theories of the Strong Interactions