Takahiro Uzu

Topic

End-of-the-world branes in AdS/BCFT

Department of Physics and Astronomy

Date & location

• Thursday, June 6, 2024
• 3:30 P.M.
• Clearihue Building, Room B017

Examining Committee

Supervisory Committee

• Dr. Kristan Jensen, Department of Physics and Astronomy, University of Victoria (Supervisor)
• Dr. Heather Russell, Department of Physics and Astronomy, UVic (Member)

External Examiner

• Dr. Mark Van Raamsdonk, Department of Physics and Astronomy, University of British Columbia

Chair of Oral Examination

• Dr. Javier Alfaro, Department of Biochemistry and Microbiology, UVic

Abstract

We investigate whether simplified models of anti-de Sitter space (AdS) terminated by an end-of-the-world (ETW) brane are a healthy dual to boundary conformal field theory (BCFT). Recent studies have shown that null trajectories starting from AdS boundary traveling to the ETW brane and back to AdS boundary can lead to singularities in the two-point function. Because such singularities does not exist on the BCFT side, they are detrimental to the healthiness of AdS/BCFT duality. We note that these singularities in BCFT two-point functions are unphysical if light takes infinite time to travel from the AdS boundary to the ETW brane in the gravitaitonal dual. Hence, we propose the condition for which the light crossing time between the AdS boundary and the ETW brane takes infinite time as a potential criterion to determine whether a bulk gravitational theory is a healthy dual to a BCFT.

In order to justify our proposal, we tested this criterion in several configurations. We first show that simplified models of empty AdS space terminated by an ETW brane do not satisfy this criterion. Then, we uncovered that adding matter in the form of a massive scalar field pushes light crossing time in the healthy direction. Next, the criterion is tested in a known stable solution of non-SUSY Janus to confirm that our criterion is in agreement. Lastly, we embedded ETW branes in three examples of AdS/CFT to see if such configurations could exist. We found a solution but the ETW brane configurations were unstable, which is supported by our solution not satisfying the light crossing time criterion.