HoloClub: “Inside an AdS Black Hole: BKL Dynamics and Trans-IR Flows” by Ayan Kumar Patra

Title: ‘Inside an AdS Black Hole: BKL Dynamics and Trans-IR Flows’

Speaker: Ayan Kumar Patra

Venue & Time: Red Room / 11:30

Abstract: The interiors of asymptotically anti-de Sitter (AdS) black holes provide a setting for extending holographic renormalisation group (RG) flows into a “trans-IR” regime behind the horizon. In this talk, I will discuss how these flows encode chaotic Belinski–Khalatnikov–Lifshitz (BKL) dynamics near a spacelike singularity and how this behaviour is reflected in a holographic probe. The oscillatory approach to the singularity consists of successive Kasner epochs, with brief transitions described as collisions with effective potential walls in a Hamiltonian billiard. I will first show how BKL dynamics arise in a class of higher-dimensional AdS black holes. I will then introduce the thermal a-function as a holographic diagnostic, interpreted as a measure of effective degrees of freedom along the flow. This function captures the sequence of Kasner epochs and eras while decreasing towards zero as the singularity is approached. Finally, I will discuss the interpretation of this limit as a trans-IR fixed point and outline possible connections between quasinormal modes, BKL dynamics, and trans-IR flows.