Events at 402 Classroom Physics South Hall, Campus

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Abstract: Minimal string theories provide some of the simplest examples of holographic dualities, where low-dimensional theories of quantum gravity are dual to matrix integrals. The most studied example is the worldsheet theory defined by the A-series minimal model coupled to Liouville CFT, which is dual to a solvable two-matrix integral. In this talk I will give an overview of low … Read More

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Abstract: We derive a convergent analytic expression for the partition function of the $\mathcal{N}=1$ $(2,4k)$ minimal superstring theory with type 0B GSO projection in the ungapped phase by leveraging the duality between this theory and a double-scaled unitary matrix integral. Taking the $k\rightarrow\infty$ limit, we also obtain the complete partition function of $\mathcal{N}=1$ JT supergravity, including all contributions associated with … Read More

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Abstract: Nahm’s construction of magnetic monopoles produced all monopoles with gauge (structure) group G=U(n).  It was generalized by Hurtubise and Murray to SO and Sp monopoles.  For any compact Lie group G, in principle, Nahm’s construction can be used to obtain monopoles in any given unitary representation of G.  For example, for G=E_8, the smallest such representation has dimension 248, … Read More

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Abstract: Primordial sources of gravitational waves (GWs) have traditionally been probed through their contribution to the stochastic GW background, detectable via pulsar timing arrays and ground-based laser interferometers. However, these same tensor perturbations can also leave an imprint on the cosmic microwave background (CMB) in the form of B-mode polarization. While a detection of primordial B-modes has long been regarded as … Read More

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Abstract: In recent years, there has been remarkable progress in evaluating wormhole amplitudes in 3d Einstein gravity with negative cosmological constant and matching them to statistics of 2d CFT data. In the talk, I will first give an overview of how wormholes in 3d gravity capture the universal matrix element statistics of local operators in 2d CFT and of certain … Read More

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Abstract: Experts have been debating whether the standard cosmology prediction for primordial deuterium agrees with observation, with some finding agreement and others finding a mild tension (~2 sigma).  I will show that this disagreement has its roots not in Big Bang Nucleosynthesis theory or nuclear physics experiment, but instead in simple statistics. I will also introduce a new method to … Read More

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Abstract: A quasimap from a curve to a GIT quotient is a map to the stack quotient that is generically stable. An open subset of quasimaps from P^1 to the flag variety, usually called Laumon space or handsaw quiver variety, is known to be closely related to the representation theory of gl_n. In particular, one can construct an action of … Read More

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The Witten index of the (2, 0)-theory compactified on spaces of the form S^3/ΓxS^2 , with a freely acting group Γ, and with external string sources implemented via timelike surface operator insertions, is expressed in terms of Ray-Singer torsion of S ^3/Γ and characters of irreducible representations of Γ. We compute it explicitly for the Dicyclic groups. The torsion and … Read More

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In this seminar, I will explain how modern ideas in quantum scattering amplitudes are being used to carry out high-precision calculations for gravitational wave emissions from binary black holes.  This includes basic ideas from effective field theory, unitarity methods, the double-copy relations between gauge and gravity theories, and modern tools for Feynman loop integration.