Thanks to Google and Blogspot for many happy years hosting this blog. However, Google has gradually stopped supporting this platform.
The engineers at Substack were kind enough to import all of my old posts to a new blog there. From now on I will post only on Substack. See you there! :-)
Replica Wormholes and Quantum Hair
https://arxiv.org/abs/2404.02331
Xavier Calmet, Stephen D.H. Hsu
We discuss recent applications of Euclidean path integrals to the black hole information problem. In calculations with replica wormholes as the next-to-leading order correction to the Gibbons-Hawking saddlepoint, the radiation density matrix approaches a pure state at late times, following the Page curve. We compare unitary evaporation of black holes (in real time), mediated by calculable quantum hair effects, with the replica wormhole results. Both replica wormhole and quantum hair approaches imply that radiation states are macroscopic superpositions of spacetime backgrounds, invalidating firewall and monogamy of entanglement constructions. Importantly, identification of modes inside the horizon with radiation modes (i.e., large scale nonlocality across the horizon) is not required to provide a physical picture of unitary evaporation. Radiation modes can encode the interior information while still remaining independent degrees of freedom.
Elizabeth Carr has always been a living symbol of fertility technology’s possibilities. Now she is the face of its challenges.
Carr, 42 years old, is the first baby born by in vitro fertilization in the U.S. Over the years she has told countless audiences how the technology made it possible for her mother to have a baby.
In the weeks since Alabama’s Supreme Court ruled that frozen embryos should be considered children, Carr has called for protections around IVF procedures—extracting eggs, fertilizing them in a lab and transferring an embryo into a uterus—that now account for some 2% of U.S. births annually.
Sen. Tim Kaine (D., Va.) said federal legislation backing IVF access would “enable the Elizabeth Carrs of the world to continue to be born.” Kaine invited Carr to accompany him on Thursday to President Biden’s State of the Union address.
“My life gives people hope,” Carr said.
The Alabama ruling is galvanizing Carr’s work in another way. Carr leads public relations and patient advocacy at Genomic Prediction, which sells genetic tests to screen embryos. Doctors can order tests for patients who want to screen for diseases and abnormalities or get an overall embryo health score. Patients and doctors can use the results to decide which embryos to transfer. Unused embryos can be stored for years. Some get discarded. ...
In Episode 351 of Hidden Forces, Demetri Kofinas speaks with Stephen Hsu, a Professor of Theoretical Physics and Computational Mathematics, Science, and Engineering at Michigan State University. Stephen is also the co-founder of multiple companies, including Genomic Prediction, which provides preimplantation genetic screening services for human embryos, and SuperFocus.ai, which builds large language models for narrow enterprise use cases.
This is a conversation about some of the most important advancements and trends in genomic science and artificial intelligence, including the social and ethical dilemmas arising from implementing these technologies at scale. Stephen and I discuss the competitive landscapes in both industries, how America’s geostrategic competition with China is driving tradeoffs between innovation and safety, the risks and opportunities that these revolutionary technologies pose, and how the world’s largest companies, economies, and military powers can work together to reap the benefits of this revolution while averting some of their most disastrous potential consequences.
