糖果派对

Speaker:听Emmanuele Battista,听Postdoc
Abstract:听In this seminar, we investigate a Schwarzschild metric whose signature changes upon crossing the event horizon. In particular, when r > 2M the metric has the usual Lorentzian signature; then, at r = 2M it becomes degenerate, and when r < 2M听 it attains the ultrahyperbolic signature. In this scenario, the time variable is real-valued outside the event horizon and becomes imaginary inside it. This geometry gives rise to what we term a Lorentzian-Euclidean black hole.听The underlying Riemann tensor exhibits Dirac-delta-like singularities which we regularize by employing the Hadamard partie finie technique. In this way, we demonstrate that the Lorentzian-Euclidean metric represents a solution of the vacuum Einstein equations. The analysis of the motion of radially moving observers reveals that the black-hole singularity can be avoided.听The seminar is based on .听

Location:听
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