Black hole evaporation: information loss but no paradox

Abstract

The process of black hole evaporation resulting from the Hawking effect has generated an intense controversy regarding its potential conflict with quantum mechanics' unitary evolution. A recent set of works by a collaboration involving one of us, have revised the controversy with the aims of, on one hand, clarifying some conceptual issues surrounding it, and, at the same time, arguing that collapse theories have the potential to offer a satisfactory resolution of the so-called paradox. Here we show an explicit calculation supporting this claim using a simplified model of black hole creation and evaporation, known as the CGHS model, together with a dynamical reduction theory, known as CSL, and some speculative, but seemingly natural ideas about the role of quantum gravity in connection with the would-be singularity. This work represents a specific realization of general ideas first discussed in [1] and a complete and detailed analysis of a model first considered in [2].

Decoding infrared imprints of quantum origins of black holes

“…Hence, semi-classical physics would suggest to substitute η f = 0.555 in Eq. (23). Thus the analysis presented above naturally adopts to the semiclassical emission rates as well.…”

Collapse of the wavefunction, the information paradox and backreaction

“…The singularity occurs when Ω = 0 and (32) gives e −2φs = κ 4 . As we have restricted ourselves to the case ρ = φ, one can use the relation (19) (or equivalently (20)), to find the value of Ω s = √ κ 4 (1 − ln κ 4 ) associated with the singularity. Therefore the location of the singularity turns out to be:…”

“…The proposal was then to associate to the intrinsic breakdown of unitary evolution, which is typical of these dynamical collapse theories, [12][13][14][15][16][17][18] (which were developed to deal with the measurement problem in standard quantum mechanics) all the information loss that takes place during the formation and subsequent Hawking evaporation of the black hole. The first concrete treatments along this line are [19,20].…”

“…The objective of the present work is to continue the research path initiated in [19]- [22] and explore an example where the remaining issue of backreaction in the setting of collapse theories. For this we will again consider a two dimensional black hole model known due to Russo-Susskind-Thorlacius (RST) [23,24] which presents a solution of the semiclassical (Einstein) equation in 2D.…”

Probing the Unruh effect with an accelerated extended system

“…In contrast, inertial thermal states are truly statistical mixtures of pure states (energy-momentum eigenstates according to inertial observers), representing the whole system -which qualifies them as proper mixed states. Although this kind of distinction may be relevant on a conceptual level -see, e.g., Ref 10. for a discussion in the context of information loss in black hole evaporation -, it plays no role for our purposes since observables restricted to the Rindler wedge cannot uncover the improper nature of the Unruh thermal bath.…”