scholarly journals Islands in de Sitter space

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Vijay Balasubramanian ◽  
Arjun Kar ◽  
Tomonori Ugajin
Keyword(s):  
Black Hole ◽  
Entanglement Entropy ◽  
De Sitter Space ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Replica Trick ◽  
Compact Geometry ◽  
Entropy Growth ◽  
Spatial Section ◽  
Conventional Field

Abstract We consider black holes in 2d de Sitter JT gravity coupled to a CFT, and entangled with matter in a disjoint non-gravitating universe. Tracing out the entangling matter leaves the CFT in a density matrix whose stress tensor backreacts on the de Sitter geometry, lengthening the wormhole behind the black hole horizon. Naively, the entropy of the entangling matter increases without bound as the strength of the entanglement increases, but the monogamy property predicts that this growth must level off. We compute the entropy via the replica trick, including wormholes between the replica copies of the de Sitter geometry, and find a competition between conventional field theory entanglement entropy and the surface area of extremal “islands” in the de Sitter geometry. The black hole and cosmological horizons both play a role in generating such islands in the backreacted geometry, and have the effect of stabilizing the entropy growth as required by monogamy. We first show this in a scenario in which the de Sitter spatial section has been decompactified to an interval. Then we consider the compact geometry, and argue for a novel interpretation of the island formula in the context of closed universes that recovers the Page curve. Finally, we comment on the application of our construction to the cosmological horizon in empty de Sitter space.

scholarly journals The price of curiosity: information recovery in de Sitter space

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lars Aalsma ◽  
Watse Sybesma
Keyword(s):  
Black Hole ◽  
Thermal Equilibrium ◽  
De Sitter Space ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Information Recovery ◽  
Fine Grained ◽  
Black Hole Radiation ◽  
Entropy Of Black Hole

Abstract Recent works have revealed that quantum extremal islands can contribute to the fine-grained entropy of black hole radiation reproducing the unitary Page curve. In this paper, we use these results to assess if an observer in de Sitter space can decode information hidden behind their cosmological horizon. By computing the fine-grained entropy of the Gibbons-Hawking radiation in a region where gravity is weak we find that this is possible, but the observer’s curiosity comes at a price. At the same time the island appears, which happens much earlier than the Page time, a singularity forms which the observer will eventually hit. We arrive at this conclusion by studying de Sitter space in Jackiw-Teitelboim gravity. We emphasize the role of the observer collecting radiation, breaking the thermal equilibrium studied so far in the literature. By analytically solving for the backreacted geometry we show how an island appears in this out-of-equilibrium state.

scholarly journals Spacetime Entanglement Entropy of de Sitter and Black Hole Horizons

2021 ◽  
Author(s):  
Abhishek Mathur ◽  
Sumati Surya ◽  
Nomaan X
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Density Matrix ◽  
Mixed State ◽  
Entanglement Entropy ◽  
Spatial Density ◽  
De Sitter Spacetime ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Sitter Spacetime

Abstract We calculate Sorkin's manifestly covariant, spacetime entanglement entropy (SSEE) for a massive and massless minimally coupled free Gaussian scalar field for the de Sitter horizon and Schwarzschild de Sitter horizons, respectively, in d > 2. In de Sitter spacetime we restrict the Bunch-Davies vacuum in the conformal patch to the static patch to obtain a mixed state. The finiteness of the spatial L2 norm in the static patch implies that the SSEE is well defined for each mode. We find that for this mixed state it is independent of the effective mass of the scalar field and matches results obtained by Higuchi and Yamamoto, where, a spatial density matrix was used to calculate the horizon entanglement entropy. Using a cut-off in the angular modes we show that the SSEE is proportional to the area of the de Sitter cosmological horizon. Our analysis can be carried over to the black hole and cosmological horizon in Schwarzschild de Sitter spacetime, which also has finite spatial L2 norm in the static regions. Although the explicit form of the modes is not known in this case, we use appropriate boundary conditions for a massless minimally coupled scalar field, to find the mode-wise SSEE for both the black hole and de Sitter cosmological horizons. As in the de Sitter calculation we see that SSEE is proportional to the horizon area in each case after taking a cut-off in the angular modes.

scholarly journals Shocks and information exchange in de Sitter space

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
L. Aalsma ◽  
A. Cole ◽  
E. Morvan ◽  
J. P. van der Schaar ◽  
G. Shiu
Keyword(s):  
Black Hole ◽  
Information Exchange ◽  
Information Transfer ◽  
Recent Progress ◽  
Vacuum State ◽  
De Sitter Space ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Black Hole Information ◽  
Selection Of

Abstract We discuss some implications of recent progress in understanding the black hole information paradox for complementarity in de Sitter space. Extending recent work by two of the authors, we describe a bulk procedure that allows information expelled through the cosmological horizon to be received by an antipodal observer. Generically, this information transfer takes a scrambling time t = H−1 log(SdS). We emphasize that this procedure relies crucially on selection of the Bunch-Davies vacuum state, interpreted as the thermofield double state that maximally entangles two antipodal static patches. The procedure also requires the presence of an (entangled) energy reservoir, created by the collection of Hawking modes from the cosmological horizon. We show how this procedure avoids a cloning paradox and comment on its implications.

scholarly journals Emergent Gravity and the Dark Universe

2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Erik Verlinde
Keyword(s):  
Black Hole Physics ◽  
Entanglement Entropy ◽  
Microscopic Theory ◽  
De Sitter Space ◽  
Elastic Response ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Baryonic Mass ◽  
Entanglement Structure ◽  
Area Law

Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a_0 =cH_0a0=cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.

scholarly journals Towards causal patch physics in dS/CFT

2018 ◽  
Vol 168 ◽  
pp. 01007 ◽  
Author(s):  
Yasha Neiman
Keyword(s):  
Field Theory ◽  
Higher Spin Gravity ◽  
De Sitter Space ◽  
Vector Model ◽  
Status Report ◽  
Quantum Field ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Higher Spin ◽  
Holographic Description

This contribution is a status report on a research program aimed at obtaining quantum-gravitational physics inside a cosmological horizon through dS/CFT, i.e. through a holographic description at past/future infinity of de Sitter space. The program aims to bring together two main elements. The first is the observation by Anninos, Hartman and Strominger that Vasiliev’s higher-spin gravity provides a working model for dS/CFT in 3+1 dimensions. The second is the proposal by Parikh, Savonije and Verlinde that dS/CFT may prove more tractable if one works in so-called “elliptic” de Sitter space – a folded-in-half version of global de Sitter where antipodal points have been identified. We review some relevant progress concerning quantum field theory on elliptic de Sitter space, higher-spin gravity and its holographic duality with a free vector model. We present our reasons for optimism that the approach outlined here will lead to a full holographic description of quantum (higher-spin) gravity in the causal patch of a de Sitter observer.

Fermion tunneling of charged particles from a non-static black hole in de Sitter space

2009 ◽  
Vol 18 (11) ◽  
pp. 4721-4725 ◽  
Author(s):  
Li Hui-Ling ◽  
Yang Shu-Zheng
Keyword(s):  
Black Hole ◽  
Charged Particles ◽  
De Sitter Space ◽  
De Sitter ◽  
Static Black Hole

scholarly journals LUKEWARM BLACK HOLES IN QUADRATIC GRAVITY

2011 ◽  
Vol 26 (14) ◽  
pp. 999-1007 ◽  
Author(s):  
JERZY MATYJASEK ◽  
KATARZYNA ZWIERZCHOWSKA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Fourth Order ◽  
Spherically Symmetric ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Quadratic Gravity ◽  
De Sitter Universe ◽  
Electrically Charged

Perturbative solutions to the fourth-order gravity describing spherically-symmetric, static and electrically charged black hole in an asymptotically de Sitter universe is constructed and discussed. Special emphasis is put on the lukewarm configurations, in which the temperature of the event horizon equals the temperature of the cosmological horizon.

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