The End of a Black Hole's Evaporation -- Part II

Abstract

We derive an explicit expression for the transition amplitude from black to white hole horizon at the end of Hawking evaporation using covariant loop quantum gravity.

Effect of the inner horizon on the black hole thermodynamics: Reissner-Nordström black hole and Kerr black hole

“…(26) It represents one of the many routes of the transformation from the black hole to the white hole. [35][36][37][38][39][40][41][42][43] It is interesting that while the formation of the gravitational white hole has extremely small probability, in hydrodynamic analog gravity the white hole horizon is easily formed as the hydraulic jump in the flowing shallow water. [44][45][46][47][48] All the considerations above demonstrated that the factor (1 + Q 2 /r 2 ) in Eqs.…”

Black to white transition of a charged black hole

“…A theory of quantum gravity must give the transition probability W (M, Q, r P , τ BH , τ t ) between the black hole state and the white hole state. For the formulation of this computation in Loop Quantum Gravity, see [5,6,10,28] A non-time-reversal-symmetric bounce can be obtained by having b and (v P , u P ) on different constant t surfaces and P and P at different radius. This gives u P = −v P and τ W H = u b − u P different from τ BH .…”

“…The spacetime described above is characterized by the region (u P < u < u P , v P < v < v P ) where the Einstein equations are not satisfied. Following [10], we call this region the B region. As mentioned in the introduction, this is the region where we assume quantum mechanics alters the classical spacetime dynamics.…”

“…The result reveals an interesting scenario: (i) black hole horizons are event horizons only in the classical limit; (ii) before the end of the evaporation, the trapping horizon tunnels into an antitrapping horizon; (iii) the black hole interior tunnels into a white hole interior; (iv) the collapsed matter bounces out. This scenario [2][3][4][5][6][7][8][9][10], its possible astrophysical implications [11][12][13][14][15][16][17][18][19][20][21][22], and its relevance for the black hole information paradox [23,24] are currently under intense investigation.…”

A high-performance code for EPRL spin foam amplitudes

“…The proliferation of spin and intertwiner labels, the difficulty of dealing with non-compact gauge groups and the difficulties with working outside of the saddle-point approximation of the semiclassical regime are all factors that limit the understanding of anything but the simplest configurations. This is an unfortunate situation since it is expected that non-trivial configurations are needed to study the dynamics of the theory or to model possible quantum gravitational phenomena [9,10,11,12].…”