arXiv subjects

D. J. Navarro

Publications and source records attributed to D. J. Navarro.

11 recordsLinked to original sources

arXiv2003

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.

hep-th↗

arXiv2001

Low-energy scattering of extremal black holes by neutral matter

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 Planck's 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.

hep-th↗

arXiv2001

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 Planck's black body radiation problem, a solution for the exact Hawking flux of evaporating Reissner-Nordstrom 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.

gr-qc↗

arXiv2000

Quantum evolution of near-extremal Reissner-Nordstrom black holes

We study the near-horizon AdS_2\timesS^2 geometry of evaporating near-extremal Reissner-Nordstrom black holes interacting with null matter. The non-local (boundary) terms t_{\pm}, 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.

hep-th↗

arXiv2000

Evaporation of charged black holes near extremality

The AdS_2\timesS^2 geometry of near-extremal Reissner-Nordstrom black holes can be described by an effective solvable model which allows to follow analytically the evaporation process including the backreaction. We find that an infinite amount of time is required for the black hole to decay to extremality.

hep-th↗

arXiv1999

Integrable models, degenerate horizons and AdS_2 black holes

The near extremal Reissner-Nordstrom black holes in arbitrary dimensions ca be modeled by the Jackiw-Teitelboim (JT) theory. The asymptotic Virasoro symmetry of the corresponding JT model exactly reproduces, via Cardy's 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.

gr-qc↗

arXiv1999

Integrable models and degenerate horizons in two-dimensional gravity

We analyse an integrable model of two-dimensional gravity which can be reduced to a pair of Liouville fields in conformal gauge. Its general solution represents a pair of ``mirror'' black holes with the same temperature. The ground state is a degenerate constant dilaton configuration similar to the Nariai solution of the Schwarzschild-de Sitter case. The existence of $ϕ=const.$ solutions and their relation with the solution given by the 2D Birkhoff's theorem is then investigated in a more general context. We also point out some interesting features of the semiclassical theory of our model and the similarity with the behaviour of AdS$_2$ black holes.

hep-th↗

arXiv1998

Bäcklund transformations in 2D dilaton gravity

We give a Bäcklund transformation connecting a generic 2D dilaton gravity theory to a generally covariant free field theory. This transformation provides an explicit canonical transformation relating both theories.

hep-th↗

arXiv1997

General Covariance and Free Fields in Two Dimensions

We investigate the canonical equivalence of a matter-coupled 2D dilaton gravity theory defined by the action functional $S = \int d^2x \sqrt{-g} (Rϕ+ V(ϕ) - 1/2 H(ϕ) (\nablaf)^2)$, and a free field theory. When the scalar field $f$ is minimally coupled to the metric field$(H(ϕ)=1)$ the theory is equivalent, up to a boundary contribution,to a theory of three free scalar fields with indefinite kinetic terms, irrespective of the particular form of the potential $V(ϕ)$. If the potential is an exponential function of the dilaton one recovers a generalized form of the classical canonical transformation of Liouville theory. When $f$ is a dilaton coupled scalar $(H(ϕ)=ϕ)$ and the potential is an arbitrary power of the dilaton the theory is also canonically equivalent to a theory of three free fields with a Minkowskian target space. In the simplest case $(V(ϕ)=0)$ we provide an explicit free field realization of the Einstein-Rosen midisuperspace. The Virasoro anomaly and the consistence of the Dirac operator quantization play a central role in our approach.

hep-th↗

arXiv1997

Free fields via canonical transformations of matter-coupled 2D 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.

hep-th↗

arXiv1994

A (1+3) Relativistic Harmonic Oscillator Simulated by an Anti-de Sitter Background

It is shown that a static $(1+3)$ anti-de Sitter metric defines, in a natural way, a relativistic harmonic oscillator in Minkowski space. The quantum theory can be solved exactly and leads to wave functions having a significantly different behaviour with respect to the non-relativistic ones. The energy spectrum coincides, up to the ground state energy, with that of the non-relativistic oscillator.

hep-th↗