Entanglement islands and braneworlds

One way to seek quantum gravity is to try combining GR and QM. In the 1970s, Hawking argued that this yields the black-hole information paradox. Basically, a black hole in his framework should radiate quantum particles entanglement with the interior, but such radiation leads the black hole to evaporate. Information inside of the black hole is then irreversibly lost, in conflict with reversibility expected in quantum theory. The information paradox implies that we are missing something when we simply force GR and QM together.

Recent work using the holographic principle—an unknown aspect of quantum gravity to Hawking in the 70s—has claimed progress towards a resolution using entanglement islands. At sufficiently late times, the emitted radiation becomes redundant with some region inside of the black hole (the island), preventing the paradox. However, one potential issue is that islands have often been found in toy models which are far removed from our own universe. Typically, either the most well-formulated models feature two spacetime dimensions or an "external bath" into which Hawking radiation leaks out. It is debatable whether the island story still provides a resolution when relaxing these limitations.

Across two separate collaborations, I have focused on finding the limits of entanglement islands within the higher-dimensional toy models with baths. I focus specifically on so-called "doubly holographic" models, in which the black hole is taken to reside in a braneworld embedded inside of a spacetime with extra dimensions. These models provide the most tractable setting in which to explore the islands.

Broadly speaking, my work has featured two directions:

Selected publications

H. Geng, A. Karch, C. Perez-Pardavila, S. Raju, L. Randall, M. Riojas, SS, Jackiw-Teitelboim Gravity from the Karch-Randall Braneworld. Physical Review Letters 129 (2022) 231601. arXiv:2206.04695, preprint June 2022.

H. Geng, A. Karch, C. Perez-Pardavila, S. Raju, L. Randall, M. Riojas, SS, Entanglement phase structure of a holographic BCFT in a black hole background. Journal of High Energy Physics 05 (2022) 153. arXiv:2112.09132, preprint Dec 2021.

H. Geng, A. Karch, C. Perez-Pardavila, S. Raju, L. Randall, M. Riojas, SS, Inconsistency of islands in theories with long-range gravity. Journal of High Energy Physics 01 (2022) 182. arXiv:2107.03390, preprint Jul 2021.

E. Caceres, A. Kundu, A. K. Patra, SS, Page curves and bath deformations. SciPost Physics Core 5 (2022) 2, 033. arXiv:2107.00022, preprint Jun 2021.

H. Geng, A. Karch, C. Perez-Pardavila, S. Raju, L. Randall, M. Riojas, SS, Information transfer with a gravitating bath. SciPost Physics 10 (2021) 5, 103. arXiv:2012.04671, preprint Dec 2020.

E. Caceres, A. Kundu, A. K. Patra, SS, Warped information and entanglement islands in AdS/WCFT, Journal of High Energy Physics 07 (2021) 004. arXiv:2012.05425, preprint Dec 2020.

In progress

H. Geng, A. Karch, C. Perez-Pardavila, L. Randall, M. Riojas, SS, M. Youssef, Proposed swampland criteria for braneworlds.