Abstract: We present a theory of gravity in which a symmetric two-index tensor in Minkowski spacetime acquires a vacuum expectation value (vev) via a potential, thereby breaking Lorentz invariance spontaneously. Two of the resulting Nambu-Goldstone modes have properties that are identical to those of the graviton in general relativity. Imposing self-consistent coupling to the energy-momentum tensor constrains the potential for the Lorentz violation. This self-consistent bootstrap leads to a nonlinear theory of gravity, containing kinetic and potential terms along with a matter coupling. At energies small compared to the Planck scale, the theory contains general relativity. Integrating out massive modes yields Lorentz-violating radiative-correction terms in the low-energy effective Lagrangian, that can lead to observable effects.
Place: Physics Dept. Meeting Room, 2th floor, IST