AT3 - Wormholes, Energy Conditions and Time Machines |
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Speaker |
Bronnikov, Kirill |
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| Talk Title |
Dynamic wormholes from nonlinear elecrodynamics in GR |
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Abstract |
We consider spherically symmetric configurations in general relativity, supported by nonlinear electromagnetic fields with gauge-invariant Lagrangians depending on the single invariant $f = F_{\mu\nu} F^{\mu\nu}$. Considering metrics with two independent functions of time, we find a natural generalization of the class of wormholes found previously by Arellano and Lobo with a time-dependent conformal factor. Such wormholes are shown to be only possible for some particular choices of the Lagrangian function $L(f)$, having no Maxwell weak-field limit. Their time evolution contains cosmological-type singularities. For general non-Maxwell $L(f)$, instead of the familiar electric-magnetic duality, there exists the so-called FP duality, connecting theories with different $L(f)$; accordingly, for some of the wormhole solutions naturally emerging with magnetic fields, the electric counterparts with the same metric are ill-defined from the viewpoint of the Lagrangian formalism. |
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