Modeling black hole evaporation fabbri aless andro
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The ingoing Eddington-Finkelstein coordinate v is, unlike in Schwarzschild, locally inertial. In this section we shall focus on the classical aspects of these black hole solutions. Only the values of the fields at the asymptotic regions are actual observables. Irrespective of the higher order terms, the coordinates £x m Eq. Had we started with a spinor field, the corresponding Vij would have been antisymmetric, in agreement with the spin-statistic connection.

See 28 Modeling Black Hole Evaporation Fig. For the left-mover sector the state-dependent function is instead simply given by 6. This arises when the curved spacetime is stationary. The other two terms, instead, can be removed without affecting the geometry. We shall now see how this approximation is realized in the action. For this reason, and for mathematical simplicity, they constructed a model neglecting the internal pressure and assumed a uniform density, see Fig.

Then, we present various approaches that exist in the literature towards the resolution of the paradox. The fundamental issue then arises as to how the effective times at different scales mesh together, leading to the concept so global and local times. We solve the Klein-Gordon equation for a scalar field, in the background geometry of a dust cloud collapsing to form a black hole, everywhere in the 1+1 spacetime: that is, both inside and outside the event horizon and arbitrarily close to the curvature singularity. The area A of the future event horizon behaves as the entropy of a closed thermodynamical system, in the sense that both quantities never decrease with time. Here it is given by 2. The microscopic explanation of it should be such that it applies equally to all possible types of black holes.

We also discuss what kind of problems can be tackled using the formalism spelled out here as well as single out future avenues of research. The quantum value of the trace is independent of the state in which the expectation value is taken. In the simplified model that we are using this can be easily done due to the free propagation implied by the wave equation of Eqs. Finally, we will derive the near-horizon limit for the nearextremal magnetically charged stringy black holes of Section 2. This is depicted in Fig.

Oscillatory approach to a singular point in the relativistic cosmology, Advances in Physics 19, pp. We find agreement with the thermal spectrum of the Hawking radiation for fermionic degrees of freedom. In recent years, a model inspired by string theory, and proposed by Callan, Giddings, Harvey and Strominger 1992 , also offers a simplified scenario which allows to study analytically the process of black hole formation and subsequent evaporation, including semiclassical backreaction effects. If this were the case, quantum tunneling could allow in principle the transfer of correlations. The four laws of black hole mechanics, Commun.

For this case all the discussion of Section 4. It is the additional integration over frequencies in the wave packets that makes the integral convergent. This in turn implies that the right-hand-side of 13 has to annihilate the Minkowski vacuum in the Rindler basis. It is natural to wonder, at this point, if there is any way to avoid the occurrence of information loss in the semiclassical approximation. At infinity it is asymptotically Minkowskian.

This is easy, since the calculation is similar to that given in the previous section. It is assumed that it has always existed and for this reason it is called an eternal black hole. The universality of gravity, nicely expressed by the equivalence principle, allows to produce an accumulative effect that can result in a very strong gravitational field. Models for Evaporating Black Holes 295 infinite burst of outgoing energy at x~, also called a thunderbolt,19 in addition to the finite energy thunderpop encountered before. However such radiation, as usual in the case of Unruh effect, has zero flux, unlike the Hawking radiation seen by the observers at right null infinity. This low energy phenomenon is sometimes regarded as the tip of a larger iceberg that dwells deeper down the black hole. First of all in these coordinates the solution takes the static form.

They indeed contain negative frequencies and this implies, as we already know, that the Rindler vacuum either for the right or the left wedge does not coincide with the Minkowski vacuum. Different choices of positive frequency solutions lead, in general, to different definitions of the vacuum state and therefore of the corresponding Fock space. If matter can fall into a black hole and disappear the entropy of matter for the external observer decreases. Things get more complicated when quantum effects are considered. Such a case can occur for some primordial black holes with Planck scale mass formed by primordial density fluctuations through the process of squeezing the zero-point quantum fluctuation of a scalar field.

In this way, the correlations existing between positive and negative x+ are transferred without distortion to correlations between positive and negative x~. The first non-zero corrections are of second order and they can never be eliminated completely by appropriate choice of the locally inertial coordinates, otherwise this will make the Riemann curvature tensor vanish at X. The collection of two-spheres of area 4? Based on this tensor we can define perceived energy densities and fluxes. The fixed background approximation ignores the effects of the radiation on the spacetime geometry, in other words, the backreaction effects. This is so, at least, when trans-Planckian physics is defined in a Lorentz-invariant way. Until now we have ignored the incoming modes at the future horizon H+. Nevertheless, quantum mechanics seems to continue conspiring against the black hole, but in a different way.