Gravity seminar - Kirill Krasnov Seminar

I will explain how in four space-time dimensions there exists not one but an infinite-parametric family of interacting theories of massless spin two particles with second order field equations. General Relativity is a special point in this theory space, the only point that exhibits the right-left (parity) symmetry. The parity-asymmetric theories arise if one changes the representation of the Lorentz group that is used to describe gravitons, and instead of symmetric trace free tensors works with a certain chiral spin 2 representation. I will explain how the new gravity theories can be described using the language of graviton scattering amplitudes. I will also describe them as certain diffeomorphism invariant SO(3)~SU(2) gauge theories.