AT5 - Constructive gravity |
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Speaker |
Stritzelberger, Nadine |
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Coauthors |
Schneider, Jonas; Schuller, Frederic P.; Stritzelberger, Nadine; Wolz, Florian |
| Talk Title |
Gravitational Closure Of Weakly Birefringent Electrodynamics |
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Abstract |
We derive the weak field gravitational dynamics of the tensorial geometry which underlies the most general linear theory of electrodynamics (Schneider, Schuller, Stritzelberger, Wolz, arXiv:1708.03870). This matter theory proves to be of particular interest in the context of standard model extensions, as it simply reduces to Maxwell electrodynamics in a limit case, while being much more general in its unreduced form and thus allowing us to describe phenomena such as birefringence in vacuo. The dynamics of the correspondingly refined spacetime geometry, tantamount to refined gravitational dynamics in this context, are obtained by gravitational closure. The recently completed method of gravitational closure systematically exploits that matter fields and their background geometry must canonically evolve together and thus ultimately takes given matter dynamics as an input and provides diffeomorphism-invariant gravitational dynamics for the geometric background as the output. Technically, the gravitational Lagrangian always arises as the solution of a countably infinite system of linear homogeneous partial differential equations. Our weak gravitational field equations are obtained by a perturbative solution of these so-called gravitational closure equations to appropriate order. We obtain the previously unknown eleven-parameter family of linearized gravitational field equations that can underpin generally linear electrodynamics, enabling us to study gravitational phenomena in the linear regime such as weak gravitational lensing or the propagation of gravitational waves. If there is any vacuum birefringence in nature, these equations replace the linearized Einstein equations and predict when and where birefringence will occur. |
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