The problem of graviton bootstrapping - Raul Carballo

Tuesday 21 Oct 2014, 11:00 → 12:00 Europe/Brussels

E/3rd floor-E.349 - Seminar room (E.349) (Marc de Hemptinne (chemin du Cyclotron, 2, Louvain-la-Neuve))

We consider the problem of the determination of the possible nonlinear theories of gravity which can be obtained by self-coupling excitations with the properties of a graviton: zero mass and spin two. This problem have received renewed interest recently in the framework of emergent gravity. We give a detailed description of the steps which are needed to find solutions to the problem and argue that, contrary to what is usually stated, there exist two preferred solutions. One of them is general relativity, as it was previously known, while the second solution we find is called unimodular gravity. Our construction constitutes a first-principles motivation for the latter theory, opening a new perspective on the cosmological constant problem in theories of emergent gravity.