Events at 402 Classroom Physics South Hall, Campus

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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

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Abstract:  The vacuum states of QCD generically break CP symmetry, and are parameterised by the ‘QCD theta’ variable. The strong CP problem arises because experiment shows that the amount of QCD CP violation must be exceedingly small, at odds with our generic expectation. This problem has a dynamical solution – the QCD axion –  which zeroes any observable effects of CP … Read More

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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

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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

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Abstract:Potential non-minimal dynamics governing the dark matter interactions can have drastic implications for their phenomenology and can inform our search strategies. In this talk I advocate for meticulous studies of a broad class of next-to-minimal models, namely Confining Dark Sectors. I will argue that such dark sectors establish a general framework that encompasses many simplified models of particle dark matter and serve … Read More

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Abstract:  Let X_0 be a rational surface with a cyclic quotient singularity (1,a)/r.  Kawamata constructed a remarkable vector bundle K_0 on X_0 such that the finite-dimensional algebra End(K_0), called the Kalck-Karmazyn algebra, “absorbs” the singularity of X_0 in a categorical sense.  If we deform over an irreducible component of the versal deformation space of X_0 (as described by Kollár and Shepherd-Barron), … Read More

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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

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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

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Self-interacting dark matter (SIDM) provides an interesting alternative to collisionless dark matter, especially when it comes to resolving small-scale structure problems. I will present our (very) preliminary findings on gravothermal collapse in SIDM halos by incorporating velocity-dependent cross sections and going beyond the Born regime for the Yukawa potential. This allows us to explore a much broader range of parameter … Read More