Talk by Dr  Joshua Kirklin, Okinawa Institute of Science and Technology, Okinawa at QASTM seminar
Channel: Sayantan Choudhury
Date: 10/04/2021

Title: Uhlmann Phase, Black Hole Information and Holography

Abstract: In the 1980s, Armin Uhlmann described a natural generalisation of Berry phase to mixed states which has come to be known as Uhlmann phase. I will describe a series of recent results characterising the Uhlmann phase of subsystems in quantum gravity. First, assuming replica wormholes contribute to the path integral, I will show that measurements of the Uhlmann phase of Hawking radiation allows one to reconstruct the phase space of the interior of a black hole (past the Page time), providing a protocol for the recovery of all infalling classical information. This is a generalisation of a previous result concerning entanglement wedges in holography. Next, I describe a path integral formula for the Uhlmann phase of a generic highly entangled system, explaining how it appears to inevitably involve an extra dimension generated by modular flow, despite a lack of any holographic assumptions. Finally, I comment on the operational meaning of Uhlmann phase, and how it's significance may relate to decoherence.

Speaker: Dr. Joshua Kirklin, Qubits and Spacetime Unit , Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.

Date and Time: 8th April, 2021, 6.30 PM to 9 PM India time (2:00 PM to 4:30 PM Berlin time).

Zoominar link: https://mpi-aei.zoom.us/j/97623339163​

Contact: Dr. Sayantan Choudhury (sayantan.choudhury@niser.ac.in)