arXiv subjects

Po-Chun Sun

Publications and source records attributed to Po-Chun Sun.

3 recordsLinked to original sources

arXiv2021

Entanglement Islands from Holographic Thermalization of Rotating Charged Black Hole

We study the time evolution of the entanglement entropy of Hawking radiation in the $(n+1)-$dimensional Kerr-Newman black hole evaporation by the holographic approach that considering the $(n+1)-$dimensional AdS eternal black brane coupled to the auxiliary CFT reservoir is in the Hartle-Hawking state. The CFT reservoir itself has a holographic dual, the $(n+2)-$dimensional bulk geometry, and the original $(n+1)-$dimensional AdS-black brane is embedded into such bulk manifold, which is precisely Randall-Sundrum model. According to the island rule [1], the entanglement entropy in semi-classical gravity can be divided into two parts, one is due to the quantum effects, which can be obtained by Ryu-Takayanagi conjecture. Another is the gravitational part, which is equal to the area of the quantum extremal surface divided by four times the Newton's constant. We show that the entanglement growth in our holographic system is linear in late times. After Page time, the system reaches saturation since the entanglement islands appear. In this paper, we will emphasize how black hole rotation affects entanglement entropy in general dimensional spacetime.

hep-th↗

arXiv2021

The Influence of Angular Momentum and Chemical Potential on Holographic Entanglement Entropy

We study the entanglement entropy between a strip region with width $2R$ and its complement in strongly coupled large-$N$ conformal field theory (CFT) on $\mathbb{R}^{1,n}$ with chemical potential and angular momentum in an thermal equilibrium state, which dual to the cylindrical Kerr-Newman black hole. Using Ryu-Takanayagi conjecture, we are able to explore the entanglement entropy through calculating the area of the extremal surface which is anchored on the entangled surface. Because we consider the rotating charged black hole for the gravitational dual, the entropy can be characterized by the mass $m$, charge $q$ and rotation $a$ parameters. We find that in the small $R$ limit, only the mass $m$ and the rotation $a$ parameters come in the leading behavior, the quadratic of $R$ term, after subtracting the entanglement entropy in vacuum. In the large $R$ limit, the area of the extremal surface is very close to the area of the event horizon after regularization. When we take the whole spatial region, the entanglement entropy is identical to the thermal entropy, i.e. the Bekenstein-Hawking entropy.

hep-th↗

arXiv2021

Holographic approach to thermalization in general anisotropic theories

We employ the holographic approach to study the thermalization in the quenched strongly-coupled field theories with very general anisotropic scalings including Lifshitz and hyperscaling violating fixed points. The holographic dual is a Vaidya-like time-dependent geometry where the asymptotic metric has general anisotropic scaling isometries. We find the Ryu-Takanayagi extremal surface and use it to calculate the time-dependent entanglement entropy between a strip region with width $2R$ and its outside region. In the special case with an isotropic metric, we also explore the entanglement entropy for a spherical region of radius $R$. The growth of the entanglement entropy characterizes the thermalization rate after a quench. We study the thermalization process in the early times and late times in both large $R$ and small $R$ limits. The allowed scaling parameter regions are constrained by the null energy conditions as well as the condition for the existence of the Ryu-Takanayagi extremal surfaces. This generalizes the previous works on this subject. All obtained results can be compared with experiments and other methods of probing thermalization.

hep-th↗