No Arabic abstract
In this paper, by setting proper boundaries in the Minkowski spacetime, we construct three toy model spacetimes, a toy black hole, a toy white hole, and a toy wormhole. Based on these model spacetimes, we discuss the Hawking radiation and the information loss problem. By counting the number of the field modes inside and outside the horizon, we show the thermal radiation of the toy black hole. We show that the white hole have a thermal absorption. We show that in the whole toy wormhole spacetime, there is no information lost. In addition, we show the black hole radiation and the white hole absorption are independent of the choices of boundary conditions at the singularity. We also show the physical effects caused by two particular boundary conditions.
An approach to black hole quantization is proposed wherein it is assumed that quantum coherence is preserved. A consequence of this is that the Penrose diagram describing gravitational collapse will show the same topological structure as flat Minkowski space. After giving our motivations for such a quantization procedure we formulate the background field approximation, in which particles are divided into hard particles and soft particles. The background space-time metric depends both on the in-states and on the out-states. We present some model calculations and extensive discussions. In particular, we show, in the context of a toy model, that the $S$-matrix describing soft particles in the hard particle background of a collapsing star is unitary, nevertheless, the spectrum of particles is shown to be approximately thermal. We also conclude that there is an important topological constraint on functional integrals.
Various techniques to tackle the black hole information paradox have been proposed. A new way out to tackle the paradox is via the use of a pseudo-density operator. This approach has successfully dealt with the problem with a two qubit entangle system for a single black hole. In this paper, we present the interaction with a binary black hole system by using an arrangement of the three qubit system of Greenberger Horne Zeilinger (GHZ) state. We show that our results are in excellent agreement with the theoretical value. We have also studied the interaction between the two black holes by considering the correlation between the qubits in the binary black hole system. The results depict a complete agreement with the proposed model. In addition to the verification, we also propose how modern detection of gravitational waves can be used on our optical setup as an input source, thus bridging the gap with the gravitational waves observational resources in terms of studying black hole properties with respect to quantum information and entanglement.
Information about the collapsed matter in a black hole will be lost if Hawking radiations are truly thermal. Recent studies discover that information can be transmitted from a black hole by Hawking radiations, due to their spectrum deviating from exact thermality when back reaction is considered. In this paper, we focus on the spectroscopic features of Hawking radiation from a Schwarzschild black hole, contrasting the differences between the nonthermal and thermal spectra. Of great interest, we find that the energy covariances of Hawking radiations for the thermal spectrum are exactly zero, while the energy covariances are non-trivial for the nonthermal spectrum. Consequently, the nonthermal spectrum can be distinguished from the thermal one by counting the energy covariances of successive emissions, which provides an avenue towards experimentally testing the long-standing information loss paradox.
In this work we show that single horizon black hole behaves as a laser. It is in many aspects conceptually analogous to Corley and Jacobson work on the two horizon black hole laser. We started by proposition that circumference of the black hole horizon holds the natural (integer) quantum number of corresponding reduced Comptons wave length of some boson systems in great canonical ensemble. For macroscopic black hole ground state is practically totally occupied while other states are practically totally unoccupied which is a typical Bose condensation. Number of the systems in this condensate represents black hole entropy. For microscopic black hole few lowest energy levels are occupied with almost equivalent population (with negative chemical potential) while all other energy states (with positive chemical potential) are practically unoccupied. It implies that here not only spontaneous but also stimulated emission of radiation comparable with spontaneous emission occurs. By Hawking evaporation any macroscopic black hole turns out in a microscopic black hole that yields, in a significant degree, coherent stimulated emission of the radiation. It implies that by total black hole evaporation there is no decoherence, i.e. information loss. Finally, a mass duality characteristic for suggested black hole model corresponding to string T-duality is discussed.
Pseudo-density matrices are a generalisation of quantum states and do not obey monogamy of quantum correlations. Could this be the solution to the paradox of information loss during the evaporation of a black hole? In this paper we discuss this possibility, providing a theoretical proposal to extend quantum theory with these pseudo-states to describe the statistics arising in black-hole evaporation. We also provide an experimental demonstration of this theoretical proposal, using a simulation in optical regime, that tomographically reproduces the correlations of the pseudo-density matrix describing this physical phenomenon.