Entropy of Hawking radiation for two-sided hyperscaling violating black branes

We construct three models to describe the scenario where two eternal black holes are separated by a flat space, and can eventually be entangled by exchanging radiation. In the doubly holographic setup, we compute the entanglement entropy and mutual information among subsystems and obtain the dynamic phase structure of the entanglement. The formation of entanglement between these two black holes is delayed by the space which the radiation must travel through. If the black holes exchange sufficient Hawking modes, the final state is characterized by a connected entanglement wedge; otherwise, the final entanglement wedge contains two separate islands. In the former case, the entanglement wedge of the black holes forms at the time scale proportional to the size of the flat space between them. While in both cases, the unitarity of the evolution is preserved. When the sizes of the black holes are not equal, we observe a loss of entanglement between the smaller black hole and the radiation at late times. On the field theory side, we consider two Sachdev-Ye-Kitaev (SYK) clusters coupled to a Majorana chain, which resemble two black holes connected by a radiation region. We numerically compute the same entanglement measures and obtain similar phase structures as the bulk results. In general, a time delay of the entanglement between the SYK clusters is found in cases with a long Majorana chain. In particular, when the SYK clusters are different in size, similar entanglement loss between the smaller SYK cluster and the Majorana chain is observed. Finally, we investigate a chain model composed of EPR clusters with particles exchanging between neighboring clusters and reproduce the features of entanglement observed in the previous models.

Section: Introductionmentioning

confidence: 99%

Black holes entangled by radiation

Liu

Xian

Peng

et al. 2022

“…The aim of the paper is to explore the generalized volume-complexity for a two-sided Hyperscaling Violating (HV) black brane [127] in d + 2 dimensions. Different aspects of this background have been studied in the literature such as: Page curve [128], Volume-Complexity [23] 6 and Action-Complexity [23,24,81]. Similar to ref.…”

Section: Jhep01(2023)105mentioning

confidence: 99%

Generalized volume-complexity for two-sided hyperscaling violating black branes

Omidi

2023

Self Cite

In this paper, we investigate generalized volume-complexity $$ \mathcal{C} $$ C gen for a two-sided uncharged HV black brane in d + 2 dimensions. This quantity which was recently introduced in [48], is an extension of volume in the Complexity=Volume (CV) proposal, by adding higher curvature corrections with a coupling constant λ to the volume functional. We numerically calculate the growth rate of $$ \mathcal{C} $$ C gen for different values of the hyperscaling violation exponent θ and dynamical exponent z. It is observed that $$ \mathcal{C} $$ C gen always grows linearly at late times provided that we choose λ properly. Moreover, it approaches its late time value from below. For the case λ = 0, we find an analytic expression for the late time growth rate for arbitrary values of θ and z. However, for λ ≠ 0, the late time growth rate can only be calculated analytically for some specific values of θ and z. We also examine the dependence of the growth rate on d, θ, z and λ. Furthermore, we calculate the complexity of formation obtained from volume-complexity and show that it is not UV divergent. We also examine its dependence on the thermal entropy and temperature of the black brane. At the end, we also numerically calculate the growth rate of $$ \mathcal{C} $$ C gen for the case where the higher curvature corrections are a linear combination of the Ricci scalar, square of the Ricci tensor and square of the Riemann tensor. We show that for appropriate values of the coupling constants, the late time growth rate is again linear.

“…Also, the analytical answer for entanglement entropy of matter is known only in some special models, including two-dimensional conformal field theory [38][39][40]. More complicated setups, such as higher-dimensional spacetimes or spacetimes with no asymptotically flat subregions, are still subjects of research [31,34,[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. As for de Sitter, the literature uses a specific setup, in which the original manifold is either initially two-dimensional or is reduced to two dimensions, and the applicability of the island formula is postulated [42,45,[58][59][60].…”

Section: Introductionmentioning

confidence: 99%

Entanglement entropy in de Sitter: no pure states for conformal matter

Ageev,

Aref’eva,

Belokon

et al. 2024

In this paper, we consider the entanglement entropy of conformal matter for finite and semi-infinite entangling regions, as well as the formation of entanglement islands in four-dimensional de Sitter spacetime partially reduced to two dimensions. We analyze complementarity and pure state condition of entanglement entropy of pure states as a consistency test of the CFT formulas in this geometrical setup, which has been previously used in the literature to study the information paradox in higher-dimensional de Sitter in the context of the island proposal. We consider two different types of Cauchy surfaces in the extended static patch and flat coordinates, correspondingly. For former, we found that entanglement entropy of a pure state is always bounded from below by a constant and never becomes zero, as required by quantum mechanics. In turn, the difference between the entropies for some region and its complement, which should be zero for a pure state, in direct calculations essentially depends on how the boundaries of these regions evolve with time. Regarding the flat coordinates, it is impossible to regularize spacelike infinity in a way that would be compatible with complementarity and pure state condition, as opposed, for instance, to two-sided Schwarzschild black hole. Finally, we discuss the information paradox in de Sitter and show that the island formula does not resolve it, at least in this setup. Namely, we give examples of a region with a time-limited growth of entanglement entropy, for which there is no island solution, and the region, for which entanglement entropy does not grow, but the island solution exists.