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Kerr festival Christchurch 2004. Reflection from horizon of black holes. Michael Kuchiev School of Physics, UNSW. Plan:. Reflection on the horizon. Escape effect from under the horizon, information extraction. Conclusion RH and EE do exist. And here Escape is possible !.
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Kerr festival Christchurch 2004 Kerr Festival 2004 Christchurch
Reflection from horizon of black holes Michael Kuchiev School of Physics, UNSW Kerr Festival 2004 Christchurch
Plan: • Reflection on the horizon • Escapeeffect from under the horizon, • information extraction • Conclusion RH and EE do exist Kerr Festival 2004 Christchurch
And here Escape is possible ! Black holes Impossible (Except for Hawking effect) What is lost is lost indeed (Что упало то пропало ) Perfect prison What happens here ? Reflection ! Kerr Festival 2004 Christchurch
Schwarzschild black hole: Kerr Festival 2004 Christchurch
Kruskal plane: Kerr Festival 2004 Christchurch
Hawking radiation: The event horizon of a (Schwarzschild) black hole has a finite temperature Kerr Festival 2004 Christchurch
Classical process – no radiation Quantum process - Hawking radiation Kerr Festival 2004 Christchurch
New effect – reflection on horizon • Classically there is no reflectionon the horizon. • Conventionally this fact is taken as a proof that the incoming particle inevitably goes inside a black hole (and stays there hereafter). • Quantum treatment reveals that there is a probability for the incoming particle to bouncefrom the horizon back, into the outside world. Kerr Festival 2004 Christchurch
Reflection on the horizon Incoming particles Reflection on horizon Black Hole Grey factor Kerr Festival 2004 Christchurch
Consider Schwarzschild black hole: Kerr Festival 2004 Christchurch
Klein-Gordon equation for scalar massless particle, s- wave Kerr Festival 2004 Christchurch
Boundary condition on the horizon: Here R is the reflection coefficient. • R=0 is the conventional assumption. • |R|>0 means that there is the reflection. Question: HOW to find R ? Kerr Festival 2004 Christchurch
Classically there is no reflection, of course Motion in conventional coordinates In Kruskal coordinates Kerr Festival 2004 Christchurch
How to verify that |R\>0 ? Idea: use analytical properties of the wave function. Consider complex plane r Im r Re r r 1 Kerr Festival 2004 Christchurch
Im Re r r 1 Analytical continuation gives: This is fundamentally important,verified below Kerr Festival 2004 Christchurch
Miracle: there is the reflection on the horizon ! Probability of reflection on the horizon: Kerr Festival 2004 Christchurch
For Kerr black holes When black holes behave as reflectors ! Kerr Festival 2004 Christchurch
Im Re r r 1 Kruskal plane: Kerr Festival 2004 Christchurch
Escape effect - particle escapes ! Kerr Festival 2004 Christchurch
Hawking process – pair production Kerr Festival 2004 Christchurch
Probability of escape Poutis the probability that the particle escapes, Pin is the probability that the particle exists inside. Kerr Festival 2004 Christchurch
Temperature bath Escape effect => radiation with temp T Kerr Festival 2004 Christchurch
No bath Radiation due to escape effect still exists. However, the information goes out ! Kerr Festival 2004 Christchurch
Conclusions: • The horizon reflects particles • A particle can escape • The information can be retrieved from under the horizon • A number of fundamental issues related to black holes are to be affected: • Black holes at early stages of the universe • Primordial black holes – interaction with matter • Entropy of black holes • Etc, there is a long way to go Kerr Festival 2004 Christchurch
Acknowledgments • Roy Kerr, thank you for the solution and the birthday party • Some results presented were obtained in collaboration with Victor Flambaum. • Support of the Australian Research Council is acknowledged. • Resources and slides from Internet were used. • Patience of the listeners is much admired. Kerr Festival 2004 Christchurch
References: M.Yu.Kuchiev, Europhys. Lett. 65, 445 (2004). M.Yu.Kuchiev, Phys.Rev.D 69, 124031 (2004). M.Yu.Kuchiev, gr-qc/0310008. M.Yu.Kuchiev and V.V.Flambaum, Scattering of scalar particles by black holes, Phys.Rev.D 69, 124031 (2004) M.Yu.Kuchiev and V.V.Flambaum, Phys. Rev D 70, 044022 (2004) M.Yu.Kuchiev, V.V.Flambaum, gr-qc/0407077 Kerr Festival 2004 Christchurch