Emergent horizon, Hawking radiation and chaos in the collapsed polymer model of a black hole

Zigdon

2018

J. High Energ. Phys.

Self Cite

We show that the state of the Hawking radiation emitted from a large Schwarzschild black hole (BH) deviates significantly from a classical state, in spite of its apparent thermal nature. For this state, the occupation numbers of single modes of massless asymptotic fields, such as photons, gravitons and possibly neutrinos, are small and, as a result, their relative fluctuations are large. The occupation numbers of massive fields are much smaller and suppressed beyond even the expected Boltzmann suppression. It follows that this type of thermal state cannot be viewed as classical or even semiclassical. We substantiate this claim by showing that, in a state with low occupation numbers, physical observables have large quantum fluctuations and, as such, cannot be faithfully described by a mean-field or by a WKB-like semiclassical state. Since the evolution of the BH is unitary, our results imply that the state of the BH interior must also be non-classical when described in terms of the asymptotic fields. We show that such a non-classical interior cannot be described in terms of a semiclassical geometry, even though the average curvature is sub-Planckian.

Section: Introductionmentioning

confidence: 60%

“…(2.54) 4 Due to the omission of the grey-body factors in this subsection, the failure is even more dramatic than what will be shown here. 5 The total density matrix is ρtot = Πj ρj.…”

Section: Jhep01(2018)136mentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Section: Jhep01(2018)136mentioning

confidence: 99%

See 2 more Smart Citations

The state of Hawking radiation is non-classical

Zigdon

2018

J. High Energ. Phys.

Self Cite

“…Another solution of this sort is found by setting α = −2 . Although a novel choice, it will be shown later that this is really an alternative description of our "collapsed polymer" model [16,29,30]. In this case and for r ≤ R , then f = 0 and…”

Section: Evading the Buchdahl Bound With Negative Pressurementioning

confidence: 99%

Resisting collapse: How matter inside a black hole can withstand gravity

2019

Phys. Rev. D

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How can a Schwarzschild-sized matter system avoid a fate of gravitational collapse?To address this question, we critically reexamine the arguments that led to the "Buchdahl bound", which implies that the minimal size of a stable, compact object must be larger than nine eighths of its own Schwarzschild radius. Following Mazur and Mottola, and in line with other counterexamples to the singularity theorems, we identify large negative radial pressure extending to the gravitational radius as the essential ingredient for evading the Buchdahl bound. Our results are novel although consistent with many other investigations of models of non-singular black holes. It is shown in particular that a large negative pressure in the framework of classical GR translates into a large positive pressure once quantum physics is incorporated. In this way, a Schwarzschild-sized bound state of closed, interacting fundamental strings in its high-temperature Hagedorn phase can appear to have negative pressure and thus the ability to resist gravitational collapse.

Non‐Singular Black Holes Interiors Need Physics Beyond the Standard Model

Fortschritte der Physik

2019

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The composition as well as the very existence of the interior of a Schwarzschild black hole (BH) remains at the forefront of interesting, open problems in fundamental physics. To address this issue, we turn to Hawking's "principle of ignorance", which says that, for an observer with limited information about a physical system, all descriptions that are consistent with known physics are equally valid. We compare three different observers who view the BH from the outside and agree on the external Schwarzschild geometry. First, the modernist, who accepts the classical BH as the final state of gravitational collapse, the singularity theorems that underlie this premise and the central singularity that the theorems predict. The modernist is willing to describe matter in terms of quantum fields in curved space but insists on (semi)classical gravity. Second is the skeptic, who wishes to evade any singular behavior by finding a loophole to the singularity theorems within the realm of classical general relativity (GR). The third is a postmodernist who similarly wants to circumvent the singularity theorems but is willing to invoke exotic quantum physics in the gravitational and/or matter sector to do so. The postmodern view suggests that the uncertainty principle can stabilize a classically singular BH in a similar manner to the stabilization of the classically unstable hydrogen atom: Strong quantum effects in the matter and gravitational sectors resolve the would-be singularity over horizon-sized length scales. The postmodern picture then requires a significant departure from (semi)classical gravity, as well as some exotic matter beyond the standard model of particle physics (SM). We find that only the postmodern framework is consistent with what is known so far about BH physics and conclude that a valid description of the BH interior needs matter beyond the SM and gravitational physics beyond (semi)classical GR.