Abstract

Theories that spontaneously break Lorentz invariance also
violate diffeomorphism symmetries. This implies the existence of
extra degrees of freedom which can be identified as Goldstone bosons
of Lorentz violation. There are two important consequences associated
with the new degrees of freedom: (1) gravity is modified and it
constrains the scale of the symmetry breaking; (2) for each Lorentz
violating term there is an associated interaction with the Goldstone
boson. We will discuss the dynamics of the Goldstone boson
interactions, including the Goldstone boson emission through Cerenkov
radiation and new 1/r^2 spin-spin force induced by Goldstone boson
exchange. They provide dramatic new signals for Lorentz violation,
complementary to the traditional tests of Lorentz violation.