scholarly journals Disentangling the thermofield-double state

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Pouria Dadras
Keyword(s):  
Field Theory ◽  
Black Hole ◽  
Strong Coupling ◽  
Entanglement Entropy ◽  
Coarse Grained ◽  
One Dimension ◽  
Leading Order ◽  
Point Function ◽  
Replica Trick ◽  
Large N

Abstract In this paper, we consider the evolution of the thermofield-double state under the double-traced operator that connects its both sides. We will compute the entanglement entropy of the resulting state using the replica trick for the large N field theory. To leading order, it can be computed from the two-point function of the theory, where, in CFTs, it is fixed by the symmetries. Due to the exponential decay of the interaction, the entanglement entropy saturates about the thermal time after the interaction is on. Next, we restrict ourselves to one dimension and assume that the theory at strong coupling is effectively described by the Schwarzian action. We then compute the coarse-grained entropy of the resulting state using the four-point function. The equality of the two entropies implies that the double-traced operators in our theory act coherently. In AdS/CFT correspondence where the thermofield-double state corresponds to a two-sided black hole, the action of a double-traced operator corresponds to shrinking or expanding the black hole in the bulk.

scholarly journals On the renormalization of entanglement entropy

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Jin-Yi Pang ◽  
Jiunn-Wei Chen
Keyword(s):  
Field Theory ◽  
Black Hole ◽  
Scalar Field ◽  
Entanglement Entropy ◽  
Black Hole Entropy ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Replica Trick ◽  
Dimensional Spacetime

AbstractThe renormalization of entanglement entropy of quantum field theories is investigated in the simplest setting with a λϕ4 scalar field theory. The 3+1 dimensional spacetime is separated into two regions by an infinitely flat 2-dimensional interface. The entanglement entropy of the system across the interface has an elegant geometrical interpretation using the replica trick, which requires putting the field theory on a curved spacetime background. We demonstrate that the theory, and hence the entanglement entropy, is renormalizable at order λ once all the relevant operators up to dimension 4 are included in the action. This exercise has a one-to-one correspondence to entanglement entropy interpretation of the black hole entropy which suggests that our treatment is sensible. Our study suggests that entanglement entropy is renormalizable and is a physical quantity.

scholarly journals Quantum information probes of charge fractionalization in large-N gauge theories

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Brandon S. DiNunno ◽  
Niko Jokela ◽  
Juan F. Pedraza ◽  
Arttu Pönni
Keyword(s):  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Entanglement Entropy ◽  
Coarse Grained ◽  
Strongly Coupled ◽  
Information Theoretic ◽  
Large N ◽  
Wide Range ◽  
Charge Fractionalization ◽  
Electric Flux

Abstract We study in detail various information theoretic quantities with the intent of distinguishing between different charged sectors in fractionalized states of large-N gauge theories. For concreteness, we focus on a simple holographic (2 + 1)-dimensional strongly coupled electron fluid whose charged states organize themselves into fractionalized and coherent patterns at sufficiently low temperatures. However, we expect that our results are quite generic and applicable to a wide range of systems, including non-holographic. The probes we consider include the entanglement entropy, mutual information, entanglement of purification and the butterfly velocity. The latter turns out to be particularly useful, given the universal connection between momentum and charge diffusion in the vicinity of a black hole horizon. The RT surfaces used to compute the above quantities, though, are largely insensitive to the electric flux in the bulk. To address this deficiency, we propose a generalized entanglement functional that is motivated through the Iyer-Wald formalism, applied to a gravity theory coupled to a U(1) gauge field. We argue that this functional gives rise to a coarse grained measure of entanglement in the boundary theory which is obtained by tracing over (part) of the fractionalized and cohesive charge degrees of freedom. Based on the above, we construct a candidate for an entropic c-function that accounts for the existence of bulk charges. We explore some of its general properties and their significance, and discuss how it can be used to efficiently account for charged degrees of freedom across different energy scales.

scholarly journals Testing the holographic principle using lattice simulations

2018 ◽  
Vol 175 ◽  
pp. 08004 ◽  
Author(s):  
Raghav G. Jha ◽  
Simon Catterall ◽  
David Schaich ◽  
Toby Wiseman
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Strong Coupling ◽  
Type Ii ◽  
Two Dimensional ◽  
Yang Mills ◽  
Large N ◽  
Gauge Gravity ◽  
Gravity Duality ◽  
Made In

The lattice studies of maximally supersymmetric Yang-Mills (MSYM) theory at strong coupling and large N is important for verifying gauge/gravity duality. Due to the progress made in the last decade, based on ideas from topological twisting and orbifolding, it is now possible to study these theories on the lattice while preserving an exact supersymmetry on the lattice. We present some results from the lattice studies of two-dimensional MSYM which is related to Type II supergravity. Our results agree with the thermodynamics of different black hole phases on the gravity side and the phase transition (Gregory–Laflamme) between them.

scholarly journals Entropic Entanglement: Information Prison Break

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Y. Yosifov ◽  
Lachezar G. Filipov
Keyword(s):  
Field Theory ◽  
Black Hole ◽  
Entanglement Entropy ◽  
Black Hole Thermodynamics ◽  
Spherically Symmetric ◽  
Quantum Field ◽  
Unitary Evolution ◽  
Local Quantum ◽  
Symmetric Black Hole ◽  
Matter Fields

We argue that certain nonviolent local quantum field theory (LQFT) modification considered at the global horizon (r=2M) of a static spherically symmetric black hole can lead to adiabatic leakage of quantum information in the form of Hawking particles. The source of the modification is (i) smooth at r=2M and (ii) rapidly vanishing at r≫2M. Furthermore, we restore the unitary evolution by introducing extra quanta which departs slightly from the generic Hawking emission without changing the experience of an infalling observer (no drama). Also, we suggest that a possible interpretation of the Bekenstein-Hawking bound as entanglement entropy may yield a nonsingular dynamical horizon behavior described by black hole thermodynamics. Hence, by treating gravity as a field theory and considering its coupling to the matter fields in the Minkowski vacuum, we derive the conjectured fluctuations of the background geometry of a black hole.

scholarly journals Holographic thermal correlators revisited

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Hare Krishna ◽  
D. Rodriguez-Gomez
Keyword(s):  
Black Hole ◽  
Leading Order ◽  
Point Function ◽  
Position Space ◽  
Conformal Dimension ◽  
General Contraction ◽  
Neutral Operator ◽  
Point Correlation ◽  
Leading Term ◽  
Geodesic Approximation

Abstract We study 2-point correlation functions for scalar operators in position space through holography including bulk cubic couplings as well as higher curvature couplings to the square of the Weyl tensor. We focus on scalar operators with large conformal dimensions. This allows us to use the geodesic approximation for propagators. In addition to the leading order contribution, captured by geodesics anchored at the insertion points of the operators on the boundary and probing the bulk geometry thoroughly studied in the literature, the first correction is given by a Witten diagram involving both the bulk cubic coupling and the higher curvature couplings. As a result, this correction is proportional to the VEV of a neutral operator Ok and thus probes the interior of the black hole exactly as in the case studied by Grinberg and Maldacena [13]. The form of the correction matches the general expectations in CFT and allows to identify the contributions of TnOk (being Tn the general contraction of n energy-momentum tensors) to the 2-point function. This correction is actually the leading term for off-diagonal correlators (i.e. correlators for operators of different conformal dimension), which can then be computed holographically in this way.

THE AVERAGE AVALANCHE SIZE IN THE MANNA MODEL AND OTHER MODELS OF SELF-ORGANIZED CRITICALITY

2013 ◽  
Vol 27 (05) ◽  
pp. 1350009 ◽  
Author(s):  
GUNNAR PRUESSNER
Keyword(s):  
Field Theory ◽  
Boundary Conditions ◽  
Higher Dimensions ◽  
One Dimension ◽  
Leading Order ◽  
Numerical Work ◽  
Avalanche Size ◽  
Self Organized ◽  
Self Organized Criticality ◽  
External Driving

The average avalanche size can be calculated exactly in a number of models of self-organized criticality (SOC). While the calculation is straight-forward in one dimension, it is more involved in higher dimensions and further complicated by the presence of different boundary conditions and different forms of external driving. Amplitudes of the leading order are determined analytically and evaluated to obtain analytical references for numerical work. A subtle link exists between the procedure to calculate the average avalanche size and the field theory of SOC.

scholarly journals Geometric secret sharing in a model of Hawking radiation

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Vijay Balasubramanian ◽  
Arjun Kar ◽  
Onkar Parrikar ◽  
Gábor Sárosi ◽  
Tomonori Ugajin
Keyword(s):  
Field Theory ◽  
Black Hole ◽  
Secret Sharing ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Three Dimensional ◽  
External Radiation ◽  
Sharing Scheme ◽  
Black Hole Interior ◽  
Pass Through

Abstract We consider a black hole in three dimensional AdS space entangled with an auxiliary radiation system. We model the microstates of the black hole in terms of a field theory living on an end of the world brane behind the horizon, and allow this field theory to itself have a holographic dual geometry. This geometry is also a black hole since entanglement of the microstates with the radiation leaves them in a mixed state. This “inception black hole” can be purified by entanglement through a wormhole with an auxiliary system which is naturally identified with the external radiation, giving a realization of the ER=EPR scenario. In this context, we propose an extension of the Ryu-Takayanagi (RT) formula, in which extremal surfaces computing entanglement entropy are allowed to pass through the brane into its dual geometry. This new rule reproduces the Page curve for evaporating black holes, consistently with the recently proposed “island formula”. We then separate the radiation system into pieces. Our extended RT rule shows that the entanglement wedge of the union of radiation subsystems covers the black hole interior at late times, but the union of entanglement wedges of the subsystems may not. This result points to a secret sharing scheme in Hawking radiation wherein reconstruction of certain regions in the interior is impossible with any subsystem of the radiation, but possible with all of it.

scholarly journals Bulk entanglement and its shape dependence

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Zhong-Ying Fan
Keyword(s):  
Kernel Method ◽  
Entanglement Entropy ◽  
Opening Angle ◽  
Leading Order ◽  
Divergent Term ◽  
Four Dimensions ◽  
Shape Dependence ◽  
Large N ◽  
Higher Dimensional ◽  
Physical Information

AbstractWe study bulk entanglement entropy in even spacetime dimensions using the heat kernel method, which captures the universal piece of entanglement entropy, a logarithmically divergent term in even dimensions. In four dimensions, we perform explicit calculations for various shapes of boundary subregions. In particular, for a cusp subregion with an arbitrary opening angle, we find that the bulk entanglement entropy always encodes the same universal information about the boundary theories as the leading entanglement entropy in the large N limit, up to a fixed proportional constant. By smoothly deforming a circle in the boundary, we find that to leading order of the deformations, the bulk entanglement entropy shares the same shape dependence as the leading entanglement entropy and hence the same physical information can be extracted from both cases. This establishes an interesting local/nonlocal relation for holographic $$\mathrm {CFT}_3$$ CFT 3 . However, the result does not hold for higher dimensional holographic theories.

scholarly journals BLACK HOLES VERSUS FIREWALLS AND THERMO-FIELD DYNAMICS

2013 ◽  
Vol 22 (12) ◽  
pp. 1342011 ◽  
Author(s):  
BORUN D. CHOWDHURY
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Conformal Field Theory ◽  
Strong Coupling ◽  
Thermal State ◽  
Heat Bath ◽  
De Sitter ◽  
Conformal Field ◽  
Thermo Field Dynamics

In this paper, we examine the implications of the ongoing black holes versus firewalls debate for the thermo-field dynamics of black holes by analyzing a conformal field theory (CFT) in a thermal state in the context of anti-de Sitter/CFT. We argue that the thermo-field doubled copy of the thermal CFT should be thought of not as a fictitious system, but as the image of the CFT in the heat bath. In case of strong coupling between the CFT and the heat bath, this image allows for free infall through the horizon and the system is described by a black hole. Conversely, firewalls are the appropriate dual description in case of weak interaction of the CFT with its heat bath.

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.

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