scholarly journals Failure of the split property in gravity and the information paradox

2022 ◽  
Author(s):  
Suvrat Raju
Keyword(s):  
Black Hole ◽  
Entanglement Entropy ◽  
Coarse Graining ◽  
The State ◽  
Information Paradox ◽  
Fine Grained ◽  
Theories Of Gravity ◽  
Split Property ◽  
The Common ◽  
Ordinary Quantum

Abstract In an ordinary quantum field theory, the “split property” implies that the state of the system can be specified independently on a bounded subregion of a Cauchy slice and its complement. This property does not hold for theories of gravity, where observables near the boundary of the Cauchy slice uniquely fix the state on the entire slice. The original formulation of the information paradox explicitly assumed the split property and we follow this assumption to isolate the precise error in Hawking’s argument. A similar assumption also underpins the monogamy paradox of Mathur and AMPS. Finally the same assumption is used to support the common idea that the entanglement entropy of the region outside a black hole should follow a Page curve. It is for this reason that computations of the Page curve have been performed only in nonstandard theories of gravity, which include a nongravitational bath and massive gravitons. The fine-grained entropy at I^{+} does not obey a Page curve for an evaporating black hole in standard theories of gravity but we discuss possibilities for coarse graining that might lead to a Page curve in such cases.

scholarly journals Dirichlet baths and the not-so-fine-grained Page curve

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Kausik Ghosh ◽  
Chethan Krishnan
Keyword(s):  
Black Hole ◽  
Entanglement Entropy ◽  
Flat Space ◽  
Information Paradox ◽  
Braneworld Cosmology ◽  
Fine Grained ◽  
Link Type ◽  
Related Approach ◽  
Set Up ◽  
Weak Gravity

Abstract We present a doubly holographic prescription for computing entanglement entropy on a gravitating brane. It involves a Ryu-Takayanagi surface with a Dirichlet anchoring condition. In braneworld cosmology, a related approach was used previously in arXiv:2007.06551. There, the prescription naturally computed a co-moving entanglement entropy, and was argued to resolve the information paradox for a black hole living in the cosmology. In this paper, we show that the Dirichlet prescription leads to reasonable results, when applied to a recently studied wedge holography set up with a gravitating bath. The nature of the information paradox and its resolution in our Dirichlet problem have a natural understanding in terms of the strength of gravity on the two branes and at the anchoring location. By sliding the anchor to the defect, we demonstrate that the limit where gravity decouples from the anchor is continuous — in other words, as far as island physics is considered, weak gravity on the anchor is identical to no gravity. The weak and (moderately) strong gravity regions on the brane are separated by a “Dirichlet wall”. We find an intricate interplay between various extremal surfaces, with an island coming to the rescue whenever there is an information paradox. This is despite the presence of massless gravitons in the spectrum. The overall physics is consistent with the slogan that gravity becomes “more holographic”, as it gets stronger. Our observations strengthen the case that the conventional Page curve is indeed of significance, when discussing the information paradox in flat space. We work in high enough dimensions so that the graviton is non-trivial, and our results are in line with the previous discussions on gravitating baths in arXiv:2005.02993 and arXiv:2007.06551.

scholarly journals Islands and Page curves of Reissner-Nordström black holes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Xuanhua Wang ◽  
Ran Li ◽  
Jin Wang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Additional Term ◽  
Current Case ◽  
Information Paradox ◽  
Extremal Surface ◽  
Four Dimensions ◽  
Black Hole Information

Abstract We apply the recently proposed quantum extremal surface construction to calculate the Page curve of the eternal Reissner-Nordström black holes in four dimensions ignoring the backreaction and the greybody factor. Without the island, the entropy of Hawking radiation grows linearly with time, which results in the information paradox for the eternal black holes. By extremizing the generalized entropy that allows the contributions from the island, we find that the island extends to the outside the horizon of the Reissner-Nordström black hole. When taking the effect of the islands into account, it is shown that the entanglement entropy of Hawking radiation at late times for a given region far from the black hole horizon reproduces the Bekenstein-Hawking entropy of the Reissner-Nordström black hole with an additional term representing the effect of the matter fields. The result is consistent with the finiteness of the entanglement entropy for the radiation from an eternal black hole. This facilitates to address the black hole information paradox issue in the current case under the above-mentioned approximations.

scholarly journals Schwarzschild black hole states and entropies on a nice slice

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
J. A. Rosabal
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Pure State ◽  
Entanglement Entropy ◽  
The State ◽  
Schwarzschild Black Hole ◽  
Complex Time ◽  
Strong Curvature

AbstractIn this work, we define a quantum gravity state on a nice slice. The nice slices provide a foliation of spacetime and avoid regions of strong curvature. We explore the topology and the geometry of the manifold obtained from a nice slice after evolving it in complex time. We compute its associated semiclassical thermodynamics entropy for a 4d Schwarzschild black hole. Despite the state one can define on a nice slice is not a global pure state, remarkably, we get a similar result to Hawking’s calculation. In the end, we discuss the entanglement entropy of two segments on a nice slice and comment on the relation of this work with the replica wormhole calculation.

scholarly journals Island in charged black holes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yi Ling ◽  
Yuxuan Liu ◽  
Zhuo-Yu Xian
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Entanglement Entropy ◽  
Information Paradox ◽  
Extremal Surface ◽  
Charged Black Holes ◽  
Dimensional Spacetime ◽  
Black Hole Information ◽  
Extremal Black Holes

Abstract We study the information paradox for the eternal black hole with charges on a doubly-holographic model in general dimensions, where the charged black hole on a Planck brane is coupled to the baths on the conformal boundaries. In the case of weak tension, the brane can be treated as a probe such that its backreaction to the bulk is negligible. We analytically calculate the entanglement entropy of the radiation and obtain the Page curve with the presence of an island on the brane. For the near-extremal black holes, the growth rate is linear in the temperature. Taking both Dvali-Gabadadze-Porrati term and nonzero tension into account, we obtain the numerical solution with backreaction in four-dimensional spacetime and find the quantum extremal surface at t = 0. To guarantee that a Page curve can be obtained in general cases, we propose two strategies to impose enough degrees of freedom on the brane such that the black hole information paradox can be properly described by the doubly-holographic setup.

The Development of Slovenia in the European Union: Social Aspects

2017 ◽  
pp. 102-108
Author(s):  
Iryna Butyrska
Keyword(s):  
Negative Impact ◽  
The State ◽  
Political Regime ◽  
The European Union ◽  
National Unity ◽  
Social Sphere ◽  
Regime Stability ◽  
Number Of Factors ◽  
The Common ◽  
The Eu

The author proves that the successful stability of independent Slovenia contributed to a number of factors, existing since its being incorporated in the SFRY. The factor, uniting the state has become the common goal – the aspiration to join the EU. The process of the European integration contributed to the modernization of a number of spheres, in particular social, cultural and economic ones. The global financial and economic crisis has revealed the turmoil in the economy of the state and its leadership was forced to gradually reduce a significant part of social privileges for the population. This caused the tension in the society and reduced the level of the national unity, having a negative impact on people’s wellbeing. However, since 2014, the Prime Minister M. Cherar has been trying to restore people’s trust in the state. The situation is getting better; indicators of trust in government are increasing, which also points to state capacity and political regime stability in Slovenia. Keywords: Slovenia, state stability, social sphere, government

Speaking for Islam

2009 ◽  
Vol 26 (3) ◽  
pp. 110-127
Author(s):  
Abdoulaye Sounaye
Keyword(s):  
Common Good ◽  
The State ◽  
Institutional Transformation ◽  
The Political ◽  
Religious Authority ◽  
The Common Good ◽  
The Common ◽  
Religion And State ◽  
Islamic Values ◽  
French Model

Unexpectedly, one of the marking features of democratization in Niger has been the rise of a variety of Islamic discourses. They focus on the separation between religion and the state and, more precisely, the way it is manifested through the French model of laïcité, which democratization has adopted in Niger. For many Muslim actors, laïcité amounts to a marginalization of Islamic values and a negation of Islam. This article present three voices: the Collaborators, the Moderates, and the Despisers. Each represents a trend that seeks to influence the state’s political and ideological makeup. Although the ulama in general remain critical vis-à-vis the state’s political and institutional transformation, not all of them reject the principle of the separation between religion and state. The Collaborators suggest cooperation between the religious authority and the political one, the Moderates insist on the necessity for governance to accommodate the people’s will and visions, and the Despisers reject the underpinning liberalism that voids religious authority and demand a total re-Islamization. I argue that what is at stake here is less the separation between state and religion than the modality of this separation and its impact on religious authority. The targets, tones, and justifications of the discourses I explore are evidence of the limitations of a democratization project grounded in laïcité. Thus in place of a secular democratization, they propose a conservative democracy based on Islam and its demands for the realization of the common good.

The Law of Contract

2018 ◽  
Author(s):  
Eva Steiner
Keyword(s):  
Common Law ◽  
World Market ◽  
Contract Law ◽  
The State ◽  
Legal Certainty ◽  
Philosophical Foundations ◽  
The Common ◽  
The Law

This chapter examines the law of contract in France and discusses the milestone reform of French contract law. While this new legislation introduces a fresh equilibrium between the contracting parties and enhances accessibility and legal certainty in contract, it does not radically change the state of the law in this area. In addition, it does not strongly impact the traditional philosophical foundations of the law of contract. The reform, in short, looks more like a tidying up operation rather than a far-reaching transformation of the law. Therefore, the chapter argues that it is questionable whether the new law, which was also intended to increase France's attractiveness against the background of a world market dominated by the Common Law, will keep its promise.

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