Showing papers on "Black hole information paradox published in 1995"
TL;DR: The mathematical and physical origin of Unruh's result is revealed, an alternative truncation scheme which may be more appropriate for black hole physics is proposed and analyzed and the thermal Hawking radiation remains unaffected even though trans-Planckian energies no longer appear.
Abstract: In a recent work, Unruh showed that Hawking radiation is unaffected by a truncation of free field theory at the Planck scale. His analysis was performed numerically and based on a hydrodynamical analogy. In the present work, by analytical methods, the mathematical and physical origin of Unruh's result is revealed. An alternative truncation scheme which may be more appropriate for black hole physics is proposed and analyzed. In both schemes the thermal Hawking radiation remains unaffected even though trans-Planckian energies no longer appear. The universality of this result is explained by working in momentum space. In that representation, in the presence of a horizon, the d'Alembertian equation becomes a singular first-order equation. In addition, the boundary conditions corresponding to the vacuum before the black hole formed are that the in modes contain positive momenta only. Both properties remain valid when the spectrum is truncated and they suffice to obtain Hawking radiation.
198 citations
TL;DR: It is argued that the Wheeler-DeWitt equation with a consistent boundary condition is only compatible with an arrow of time that formally reverses in a recollapsing universe, and that collapsing matter must start reexpanding ``anticausally'' (controlled by the reversed arrow) before horizons or singularities can form.
Abstract: We argue that the Wheeler-DeWitt equation with a consistent boundary condition is only compatible with an arrow of time that formally reverses in a recollapsing universe To recover a classically recollapsing universe in terms of wave packets, we impose the usual boundary condition of excluding exponentially increasing wave functions for large scale factors Consistency of these opposite arrows is then facilitated by quantum effects in the region of the classical turning point We also discuss in this context the meaning of the time-asymmetric expression used in the definition of ``consistent histories'' Since gravitational time dilation diverges at horizons, one has to conclude that collapsing matter must start reexpanding ``anticausally'' (controlled by the reversed arrow) in this scenario before horizons or singularities can form There would then also be no mass inflation nor any information loss paradox
96 citations
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TL;DR: A concise survey of the black hole information paradox and its current status is given in this article, where a summary is also given of recent arguments against remnants, namely unitarity and causality, which would imply that Reissner Nordstrom black holes have infinite internal states.
Abstract: A concise survey of the black hole information paradox and its current status is given. A summary is also given of recent arguments against remnants. The assumptions underlying remnants, namely unitarity and causality, would imply that Reissner Nordstrom black holes have infinite internal states. These can be argued to lead to an unacceptable infinite production rate of such black holes in background fields. (To appear in the proceedings of the PASCOS symposium/Johns Hopkins Workshop, Baltimore, MD, March 22-25, 1995).
73 citations
01 Apr 1995
TL;DR: In this article, a possible resolution of the information loss paradox is proposed, which is fully in accord with the rules of quantum mechanics, and the remaining information is causally separated from the external world in the expanding horn of a black hole or cornucopion.
Abstract: In these lectures, the author's point of view on the problem of Hawking Evaporation of Black Holes is explained in some detail. A possible resolution of the information loss paradox is proposed, which is fully in accord with the rules of quantum mechanics. Black hole formation and evaporation leaves over a remnant which looks pointlike to an external observer with low resolving power, but actually contains a new infinite asymptotic region of space. Information can be lost to this new region without violating the rules of quantum mechanics. However, the thermodynamic nature of black holes can only be understood by studying the results of measurements that probe extremely small (sub-Planck scale) distances and times near the horizon. Susskind's description of these measurements in terms of string theory may provide an understanding of the Bekenstein-Hawking (BH) entropy in terms of the states of stranded strings that cross the horizon. The extreme nonlocality of string theory when viewed at short time scales allows one to evade all causality arguments which pretend to prove that the information encoded in the BH entropy can only be accessed by the external observer in times much longer than the black hole evaporation time. The present author believes however that the information lost in black hole evaporation is generically larger than the BH entropy, and that the remaining information is causally separated from the external world in the expanding horn of a black hole remnant or cornucopion. The possible observational signatures of such cornucopions are briefly discussed.
62 citations
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TL;DR: In this paper, the authors studied the black hole formation and evaporation in the semiclassical approximation in simple 1+1-dimensional models, with emphasis on issues related to Hawking's information paradox.
Abstract: Black hole formation and evaporation is studied in the semiclassical approximation in simple 1+1-dimensional models, with emphasis on issues related to Hawking's information paradox. Exact semiclassical solutions are described and questions of boundary conditions and vacuum stability are discussed. The validity of the semiclassical approximation has been called into question in the context of the information puzzle. A different approach, where black hole evolution is assumed to be unitary, is described. It requires unusual causal properties and kinematic behavior of matter that may be realized in string theory.
50 citations
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TL;DR: Is string theory relevant to the black hole information problem? as mentioned in this paper investigates the connection between string theory and black hole black hole problems and presents an attempt to clarify some of the issues involved.
Abstract: Is string theory relevant to the black hole information problem? This is an attempt to clarify some of the issues involved. Presented at Strings '95.
44 citations
TL;DR: In this article, the authors analyze a system consisting of an oscillator coupled to a field and show that the oscillator loses coherence on a very short decoherence timescale but, on a much longer relaxation timescale, predictably evolves into a unique, pure (ground) state.
Abstract: We analyze a system consisting of an oscillator coupled to a field. With the field traced out as an environment, the oscillator loses coherence on a very short {\it decoherence timescale}; but, on a much longer {\it relaxation timescale}, predictably evolves into a unique, pure (ground) state. This example of {\it re-coherence} has interesting implications both for the interpretation of quantum theory and for the loss of information during black hole evaporation. We examine these implications by investigating the intermediate and final states of the quantum field, treated as an open system coupled to an unobserved oscillator.
40 citations
01 Jun 1995
TL;DR: In this paper, the physical degrees of freedom and the dynamics of their evolution at the Planck length were investigated by performing thought experiments with black holes, and the results showed that the degree of freedom of a black hole is at most a constant.
Abstract: The physical degrees of freedom and the dynamics of their evolution at the Planck length are investigated by performing thought experiments with black holes.
26 citations
TL;DR: In this article, the authors review the quantum physics of large Schwarzschild black holes and discuss how the ideas of black hole complementarity may be realized in string theory, and argue that the world may be a hologram.
Abstract: In these lectures we review the quantum physics of large Schwarzschild black holes. Hawking's information paradox, the theory of the stretched horizon and the principle of black hole complementarity are covered. We then discuss how the ideas of black hole complementarity may be realized in string theory. Finally, arguments are given that the world may be a hologram. Lectures delivered at ICTP Spring School on String Theory, Gauge Theory, and Quantum Gravity, 1995.
21 citations
TL;DR: In this article, a unitary quantum theory of the CGHS model of 2D dilaton gravity was constructed by performing a reduced phase space quantization, and it was shown that physical states exist such that in the semiclassical limit the Hawking radiation is present.
19 citations
TL;DR: The main purpose is to propose a mechanism of black hole decay in terms of a time evolution of the wave function defined on the minisuperspace, and introduce the superposition principle and the time-dependent Schr\"odinger equation which lead to the uncertainty of the Hamiltonian eigenvalue.
Abstract: We develop a quantum description of spherically symmetric gravitational collapse of a massless scalar field. The canonical quantization procedure is applied to a minisuperspace model in which the four-metric and scalar field variables are restricted to a self-similar functional form. Our main purpose is to propose a mechanism of black hole decay in terms of a time evolution of the wave function defined on the minisuperspace. For the self-similar classical dynamics there exists a one-parameter family of solutions for the Einstein-scalar equations, and the Hamiltonian turns out to play the role of the critical parameter which separates the supercritical solution corresponding to a black hole formation from the subcritical one corresponding to a wave reflection to infinity. We derive a set of the eigenfunctions of the quantum Hamiltonian operator, which is interpreted to be the quantum version of the supercritical and subcritical solutions. One of the metric components is also treated as a quantum operator which does not commute with the Hamiltonian operator. The expansion of the eigenfunction of the metric operator in terms of the Hamiltonian eigenfunctions motivates us to introduce the superposition principle and the time-dependent Schr\"odinger equation which lead to the uncertainty of the Hamiltonian eigenvalue. Then we study the time evolution of the initial black hole state, which is chosen to be one of the supercritical Hamiltonian eigenstates. We arrive at the conclusion that the time evolution toward black hole decay is essentially due to the breakdown of orthogonality of the Hamiltonian eigenfunctions: The quantum black hole behaves like a wave packet written by a superposition of the various subcritical states. The localized structure of the black hole wave packet begins to spread as each subcritical state evolves with time according to the Schr\"odinger equation. We can estimate the decay time and find the final behavior of the wave function describing an outgoing flux of scalar waves observable at future null infinity.
TL;DR: In this article, the authors examined the extent to which nonlocal effects show up in the perturbative S-matrix of string theory and showed that the consistency of quantum theory with black hole physics requires nonlocality not present in ordinary effective field theory.
Abstract: It has been argued that the consistency of quantum theory with black hole physics requires nonlocality not present in ordinary effective field theory. We examine the extent to which such nonlocal effects show up in the perturbative S-matrix of string theory.
TL;DR: In this article, the authors examined the extent to which nonlocal effects show up in the perturbative S-matrix of string theory and showed that the consistency of quantum theory with black hole physics requires nonlocality not present in ordinary effective field theory.
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TL;DR: In this paper, a generalization of the effective action for the two-dimensional CGHS model is presented, which removes certain curvature singularities arising for the original theory and shows that the flux of Hawking radiation is identical to that encountered in other 2D models.
Abstract: The two-dimensional CGHS model provides an interesting toy-model for the study of black hole evaporation. For this model, a quantum effective action, which incorporates Hawking radiation and backreaction, can be explicitly constructed. In this paper, we study a generalization of this effective action. In our extended model, it is possible to remove certain curvature singularities arising for the original theory. We also find that the flux of Hawking radiation is identical to that encountered in other two-dimensional models.
TL;DR: In this article, a model detector for field quanta is considered from the point of view of a quantum field theory defined in asymptotically stationary regions of the Kruskal manifold and from that of a theory restricted to a Schwarzschild coordinate patch.
Abstract: A model detector for field quanta is considered from the point of view of a quantum field theory defined in asymptotically stationary regions of the Kruskal manifold and from that of a theory restricted to a Schwarzschild coordinate patch. A spherical array of oscillators at a constant distance r from the black hole, harmonic with respect to their proper time, is coupled to spherically symmetric Schwarzschild-modes of the field. The system is quantized and the energy expectation value of the coupled harmonic oscillators in a state of the field representing Hawking radiation is calculated. The back-reaction to the field may be interpreted in two controversial ways: In terms of the quantum field theory restricted to Schwarzschild space-time there is merely some scattering of the Hawking radiation, whereas in the framework of Kruskal quantum field theory particle production occurs.
01 Jan 1995
TL;DR: In this paper, a statistical mechanics description of particles, fields and spacetime based on the concept of quantum open systems and the influence functional formalism has been introduced, which reproduces in full the established theory of quantum fields in curved spacetime and contains also a microscopic description of their statistical properties, such as noise, fluctuations, decoherence, and dissipation.
Abstract: In recent years a statistical mechanics description of particles, fields and spacetime based on the concept of quantum open systems and the influence functional formalism has been introduced. It reproduces in full the established theory of quantum fields in curved spacetime and contains also a microscopic description of their statistical properties, such as noise, fluctuations, decoherence, and dissipation. This new framework allows one to explore the quantum statistical properties of spacetime at the interface between the semiclassical and quantum gravity regimes, as well as important non-equilibrium processes in the early universe and black holes, such as particle creation, entropy generation, galaxy formation, Hawking radiation, gravitational collapse, backreaction and the black hole end-state and information lost issues. Here we give a summary of the theory of correlation dynamics of quantum fields and describe how this conceptual scheme coupled with scaling behavior near the infrared limit can shed light on the black hole information paradox.
TL;DR: In this article, a new universal method to determine the tortoise coordinate transformation in a non-static space-time was proposed and the Hawking temperatures of several spherically symmetric nonstatic black holes were shown by means of the new method.
Abstract: A new universal method to determine the tortoise-coordinate transformation in a non-static space-time is proposed. The Hawking temperatures of several spherically symmetric non-static black holes are shown by means of the new method.
23 Feb 1995
TL;DR: In this paper, it is argued that taming of these weak values by back-reaction may lead to geometrical backgrounds which are also build from weak values of the gravitational field operators.
Abstract: In conventional field theories, the emission of Hawking radiation in the background of a collapsing star requires transplanckian energy fluctuations. These fluctuations are encoded in the weak values of the energy-momentum operator constructed from matrix elements between both -in and -out states. It is argued that taming of these weak values by back-reaction may lead to geometrical backgrounds which are also build from weak values of the gravitational field operators. This leads to different causal histories of the black hole as reconstructed by observers crossing the horizon at different times but reduces, in accordance with the equivalence principle, to the classical description of the collapse for the proper history of the star as recorded by an observer comoving with it. For observers never crossing the horizon, the evaporation would be interpreted within a topologically trivial ``achronon geometry" void of horizon and singularity: after the initial ignition of the radiation from pair creation out of the vacuum of the collapsing star of mass M, as in the conventional theory, the source of the thermal radiation would shift gradually to the star itself in a time at least of order $4M\ln 2M$. The burning of the star could be consistent with a quantum unitary evolution along the lines suggested by 't Hooft. A provisional formal expression of general black hole complementarity is proposed and its possible relevance for testing features of a theory of quantum gravity is suggested.
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TL;DR: In this paper, a statistical mechanics description of particles, fields and spacetime based on the concept of quantum open systems and the influence functional formalism has been introduced, which reproduces in full the established theory of quantum fields in curved spacetime and contains also a microscopic description of their statistical properties, such as noise, fluctuations, decoherence, and dissipation.
Abstract: In recent years a statistical mechanics description of particles, fields and spacetime based on the concept of quantum open systems and the influence functional formalism has been introduced. It reproduces in full the established theory of quantum fields in curved spacetime and contains also a microscopic description of their statistical properties, such as noise, fluctuations, decoherence, and dissipation. This new framework allows one to explore the quantum statistical properties of spacetime at the interface between the semiclassical and quantum gravity regimes, as well as important non-equilibrium processes in the early universe and black holes, such as particle creation, entropy generation, galaxy formation, Hawking radiation, gravitational collapse, backreaction and the black hole end-state and information lost issues. Here we give a summary of the theory of correlation dynamics of quantum fields and describe how this conceptual scheme coupled with scaling behavior near the infrared limit can shed light on the black hole information paradox.