Talk detail

Participant	Düll, Maximilian
Institution	Center for Astronomy, Heidelberg University - Philosophenweg 12 - Heidelberg - Baden-Württemberg - Germany

Session	AT5	Accepted		Order	Time
Talk	Oral abstract	Title	Refinement of Friedmann equations implied by vacuum birefringence
Coauthors
Abstract	Birefringence is a well-studied phenomenon in materials, but its absence in vacuo is deeply encoded into the spacetime structure of general relativity and the standard model of particle physics. This talk now presents the cosmological implications of replacing standard Maxwell theory by a generalization allowing for vacuum birefringence. This is possible since the recently developed gravitational closure procedure allows one to start with this birefringent matter theory and to derive the causally compatible and diffeomorphism-invariant gravitational Lagrangian for the correspondingly refined background geometry -- by mere solution of a countable set of linear homogeneous closure equations. This is still a hard mathematical task, but we show how the assumptions of homogeneity and isotropy of the refined spacetime background can be employed in order to exactly obtain the appropriately refined Friedmann equations.
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