# Seminars & Colloquia Calendar

WIP Seminar

## The weak second Bianchi identity for spacetimes with timelike singularities

Location:  Hill 703
Date & time: Wednesday, 30 January 2019 at 11:00AM - 12:30PM

Abstract:   The twice-contracted second Bianchi identity is automatically satisfied for smooth Lorentzian manifolds.  If their metric solves the Einstein equations with energy-momentum-stress tensor of a matter field'' as the source of spacetime curvature, this identity implies the physical laws of energy and momentum conservation for that field.

In this talk I explain how to obtain a distributional version of  this identity, for spherically- symmetric spacetimes with time-like singularities, so long as the associated curvature blow-up is not too severe.   A necessary condition for the weak identity to hold is the local integrability of the energy-momentum density of the field of a point charge, which is fulfilled by a large family of electromagnetic vacuum laws.  This family includes the Born-Infeld law but it does NOT include the traditional linear vacuum law of Maxwell.

(joint work with A. Burtscher and M. Kiessling)

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