D. J. Navarro

Holography, degenerate horizons and entropy

Abstract We show that a realization of the correspondence AdS 2 /CFT 1 for near extremal Reissner–Nordstrom black holes in arbitrary dimensional Einstein–Maxwell gravity exactly reproduces, via Cardys formula, the deviation of the Bekenstein–Hawking entropy from extremality. We also show that this mechanism is valid for Schwarzschild–de Sitter black holes around the degenerate solution dS 2 ×S n . These results reinforce the idea that the Bekenstein–Hawking entropy can be derived from symmetry principles.

Quantum evolution of near-extremal Reissner–Nordström black holes

Abstract We study the near-horizon AdS 2 × S 2 geometry of evaporating near-extremal Reissner–Nordstrom black holes interacting with null matter. The non-local (boundary) terms t ± , coming from the effective theory corrected with the quantum Polyakov–Liouville action, are treated as dynamical variables. We describe analytically the evaporation process which turns out to be compatible with the third law of thermodynamics, i.e., an infinite amount of time is required for the black hole to decay to extremality. Finally we comment briefly on the implications of our results for the information loss problem.

Free fields via canonical transformations of matter-coupled two-dimensional dilaton gravity models

It is shown that the 1+1-dimensional matter-coupled Jackiw-Teitelboim model and the model with an exponential potential can be converted by means of appropriate canonical transformations into a bosonic string theory propagating on a flat target space with an indefinite signature. This makes it possible to consistently quantize these models in the functional Schroedinger representation thus generalizing recent results on CGHS theory.

Evaporation of near-extremal Reissner-Nordström black holes.

The formation of near-extremal Reissner-Nordström black holes in the S-wave approximation can be described, near the event horizon, by an effective solvable model. The corresponding one-loop quantum theory remains solvable and allows one to follow analytically the evaporation process, which is shown to require an infinite amount of time.

Low-energy scattering of extremal black holes by neutral matter

Abstract We investigate the decay of a spherically symmetric near-extremal charged black hole, including back-reaction effects, in the near-horizon region. The non-locality of the effective action controlling this process allows and also forces us to introduce a complementary set of boundary conditions which permit to determine the asymptotic late time Hawking flux. The evaporation rate goes down exponentially and admits an infinite series expansion in Plancks constant. At leading order it is proportional to the total mass and the higher order terms involve higher order momenta of the classical stress-tensor. Moreover, we use this late time behaviour to go beyond the near-horizon approximation and comment on the implications for the information loss paradox.

A Planck-Like Problem for Quantum Charged Black Holes

Motivated by the parallelism existing between the puzzles of classical physics at the beginning of the XXth century and the current paradoxes in the search of a quantum theory of gravity, we give, in analogy with Plancks black body radiation problem, a solution for the exact Hawking flux of evaporating Reissner-Nordström black holes. Our results show that when back-reaction effects are fully taken into account the standard picture of black hole evaporation is significantly altered, thus implying a possible resolution of the information loss problem.

Late time correlators in semiclassical particle black hole scattering

We analyse the quantum corrected geometry and radiation in the scattering of extremal black holes by low-energy neutral matter. We point out the fact that the correlators of local observables inside the horizon are the same as those of the vacuum. Outside the horizon the correlators at late times are much bigger than those of the (thermal) case obtained neglecting the backreaction. This suggests that the corrected Hawking radiation could be compatible with unitarity.

Integrable models, degenerate horizons and AdS2 black holes

Abstract The near extremal Reissner-Nordstrom black holes in arbitrary dimensions can be modeled by the Jackiw-Teitelboim (JT) theory. The asymptotic Virasoro symmetry of the corresponding JT model exactly reproduces, via Cardys formula, the deviation of the Bekenstein-Hawking entropy of the Reissner-Nordstrom black holes from extremality. We also comment how can we extend this approach to investigate the evaporation process.