On the assumptions leading to the information loss paradox

Abstract

The information loss paradox is usually stated as an incompatibility between general relativity and quantum mechanics. However, the assumptions leading to the problem are often overlooked and, in fact, a careful inspection of the main hypothesises suggests a radical reformulation of the problem. Indeed, we present a thought experiment involving a black hole that emits radiation and, independently of the nature of the radiation, we show the existence of an incompatibility between (i) the validity of the laws of general relativity to describe infalling matter far from the Planckian regime, and (ii) the so-called central dogma which states that as seen from an outside observer a black hole behaves like a quantum system whose number of degrees of freedom is proportional to the horizon area. We critically revise the standard arguments in support of the central dogma, and argue that they cannot hold true unless some new physics is invoked even before reaching Planck scales. This suggests that the information loss problem, in its current formulation, is not necessarily related to any loss of information or lack of unitarity. Therefore, in principle, semiclassical general relativity and quantum mechanics can be perfectly compatible before reaching the final stage of the black hole evaporation where, instead, a consistent theory of quantum gravity is needed to make any prediction.

29 pages, 4 figures. v2: minor modifications and references added

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Cited by in corpus (8)

• Entanglement Phase Structure of a Holographic BCFT in a Black Hole Background
• BCFT in a Black Hole Background: An Analytical Holographic Model
• Defect extremal surfaces for entanglement negativity
• Paradoxes before the paradox: surface gravity and the information loss problem
• Reflected Entropy and Entanglement Negativity for Holographic Moving Mirrors
• Asymptotic safety, quantum gravity, and the swampland: a conceptual assessment
• Resolving information loss paradox with Euclidean path integral
• Black holes and their horizons in semiclassical and modified theories of gravity