Abstract: Holographic conformal field theories exhibit dramatic changes in the structure of their operator algebras in the limit where the number of local degrees of freedom (N) becomes infinite. An important example of such phenomena is the violation of the additivity property for algebras associated to local subregions. I will first review several examples of superadditive algebras in quantum field theory and … Read More

Abstract: We construct L-functions for general modular-invariant 2D CFTs, providing an analytic language for studying high-energy spectra and their resolution. We apply this tool to the modular bootstrap at large central charge. This leads to some considerations of chaos and spectral rigidity in 2D CFT.

Abs: A key question in holography is how to reconstruct bulk operators in the holographic dual. It is especially interesting to reconstruct operators inside the black hole interior, but also especially difficult to do explicitly. Recently, an explicit form for the bulk-to-boundary `holographic’ map was proposed in JT gravity, by Iliesiu, Levine, Lin, Maxfield, and Mezei, who also proposed and … Read More

The double scaled SYK model provides perhaps the simplest example of holography. It admits a diagrammatic expansion in chord diagrams, and these chords directly capture geometric information about the dual spacetime. Probe matter in the bulk corresponds to adding other types of chords. I will briefly review that, and then discuss deformations of the model where such matter becomes dynamical. … Read More

Generalized entanglement wedges (“holograms”) exist in arbitrary spacetimes. They exhibit suggestive properties such as strong subadditivity, nesting, and no-cloning.  But the entanglement wedges of AdS boundary regions satisfy an additional condition, complementarity: for a boundary subregion $B$ with boundary complement $\bar B$, minEW($B$) is the bulk complement of maxEW$(\bar B)$.  Here we refine the definition of holograms and prove that … Read More

Abstract: In a spacetime with asymptotically anti-de-Sitter boundaries, localized bulk events produce characteristic signals at boundary locations lightlike-separated from the event. We describe (thought) experiments that use boundary wavepackets to amplify these signals and explain how to quantitatively read off the bulk scattering amplitudes and bulk geometry around essentially any bulk point.  We also discuss some new signatures of bulk … Read More

Abstract: Studies of spacetime wormholes have led to the understanding of important physics. But some wormhole saddles seem to lead to contradictions with AdS/CFT (even with ensembles of CFTs). One would expect this to be sorted out by determining which saddles are “relevant” or “stable,” but confusions remain. In particular, despite a number of recent Euclidean stability analyses, axion wormholes remain a … Read More

We introduce a new algebraic framework to describe gravitational scrambling, including the semiclassical limit of any out-of-time-order correlation function that consists of s-wave operator insertions separated by approximately the scrambling time. This algebra, which we call a modular-twisted product, is defined starting from two half-sided modular inclusions of von Neumann algebras, interpreted physically as the large N limit of products … Read More