Würzburg 2018 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 3: Alternative theories of gravity and general formalism

GR 3.5: Talk

Tuesday, March 20, 2018, 17:50–18:10, NW-Bau - HS3

Friedmann equations for gravity underlying birefringent electrodynamics — •Maximilian Düll and Nils Fischer — Universität Heidelberg

In recent years, it has become clear how quantizable matter fields determine the gravitational theory of the spacetime on which those matter fields live. This procedure - the gravitational closure of matter field equations - in the end boils down to finding the gravitational action as a solution of a set of partial differential equations that have been constructed from the prescribed matter dynamics. In this talk, we will show how appropriate symmetry assumptions - namely spatial homogeneity and isotropy - greatly simplify this problem of finding the appropriate gravitational action. We will illustrate the procedure with two explicit examples - the standard case of Friedmann-Robertson-Walker cosmology for a metric spacetime and cosmology for a spacetime with possible birefringence in vacuum.