Cornell University

During the spring semester, in-person concerts, events and lectures that involve outside guests will not be held, per the university’s COVID-19 travel and visitor policy.

This is a past event. Its details are archived for historical purposes.

The contact information may no longer be valid.

Please visit our current events listings to look for similar events by title, location, or venue.

Rescuing a black hole in the large-q coupled SYK model

Friday, January 15, 2021 at 12:00pm to 1:00pm

Virtual Event

 Yuri Lensky, PhD Stanford --  Bethe/KIC presentation 

Title: Rescuing a black hole in the large-q coupled SYK model


In this paper, we develop a general effective theory for two copies of the Sachdev-Ye-Kitaev (SYK) model with a time-dependent bilinear coupling. For a quantum quench problem with an initial state of the thermofield double state, we show how the evolution of the system is described by a complex reparametrization field with a classical Hamiltonian. We study correlation functions in this system and compare the large-q theory with the bulk low energy effective theory. In particular, we study the special case of a ``rescued black hole'', which describes how a time-evolved thermofield double state can evolve to the ground state of a coupled SYK model by a carefully tuned time-dependent coupling. In the low energy region, there is a holographic dual interpretation, which is a geometry that crosses over from an eternal black hole to a global AdS2 vacuum. This family of geometries allow us to access the bulk region that would be the black hole interior without the rescue process. By comparing the large-q and low energy theory, we find that even in the low energy region the deviation from the low energy theory cannot be neglected if the rescue process starts late. This provides evidence that the low energy effective theory of the bulk fails near the inner horizon of the black hole. We note the possibility of a connection to a two-dimensional analog of the higher-dimensional black hole singularity.


Hosted by: Eun-Ah Kim, Debanjan Chowdhury, Chao-Ming Jian, and LASSP Theory Group


Dial-In Information

Join Zoom Meeting


Meeting ID: 926 5397 3078

Passcode: 981488

Google Calendar iCal Outlook
Event Type



LASSP, Physics


physics, lassp

Contact E-Mail

Contact Name

Trisica Munroe

Contact Phone



Yuri Lensky

Speaker Affiliation

Stanford University

Dept. Web Site

Open To

Cornell community

Recent Activity