Speaker
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In 1973, Bardeen, Carter and Hawking announced the celebrated four laws of black hole thermodynamics, by analogy with the laws of thermodynamics. However, recent works suggest that the third law - stating that an extremal black hole cannot be formed from regular conditions in a finite time - could be incorrect.
We investigate the formation of extremal black holes with our null coordinates code for the evolution of a charged scalar field in a regular centre configuration, similarly to the work of Gelles and Pretorius in a null rectangle configuration. Using a one parameter family of initial data, we find a jump in the black hole charge-to-mass ratio leading, on the upper side of it, to black holes arbitrarily close to extremality. We give numerical evidence that the set of initial parameters collapsing into asymptotically extremal black holes is codimension one.
Furthermore, we study the behaviour of evolutions resulting in near extremal black holes and in particular we observe several of the evolution characteristics scaling with the distance to extremality.