[HEG] "Filtering" CFTs at large N: Euclidean Wormholes, Closed Universes, and Black Hole Interiors

Who: Hong Liu (MIT)
Title: "Filtering" CFTs at large N: Euclidean Wormholes, Closed Universes, and Black Hole Interiors

Abstract:

Despite its successes, the large-N holographic dictionary remains incomplete. Key features of gravitational path integrals--most notably Euclidean wormholes and the associated failure of factorization--lack a clear interpretation in the standard large-N framework. In this talk, we discuss a resolution of the puzzle by introducing a large-N filter, which provides an intrinsic boundary definition of gravitational "averages,'' and a boundary explanation of the origin of wormholes as well as their amplitudes. In addition, we derive an infinite tower of inequalities constraining wormhole amplitudes. 

Beyond resolving factorization, the large-N filter supplies a generalized framework from which richer Lorentzian spacetime structures can emerge, including closed universes and black hole interiors. We argue that both closed universes and black hole interiors are quantum volatile, and that an AdS spacetime entangled with a baby universe is likewise quantum volatile. This volatility may allow an observer in AdS to infer the existence of the baby universe, whereas for an infalling observer crossing a black hole horizon, the ability to make measurements after  may become fundamentally limited--even if they may not live long enough to notice.