Isabel Garcia-Garcia | Abelian Instantons in Quantum Field Theory and Gravity | April 17, 2026
I will discuss field configurations of Abelian gauge fields that carry non-zero second Chern number, generated by closed monopole worldlines in four-dimensional Euclidean space. These "Abelian instantons" render the electromagnetic vacuum angle physical. In the presence of gravity, magnetic monopoles that are Reissner-Nordstrom black holes naturally realize these field configurations. Including these instantons in the gravitational path integral makes the electromagnetic theta-term a physical parameter of the Standard Model coupled to gravity.
Ahmed Almheiri (NYU/AIS) | Continuing past the inner horizon using WKB | April 10, 2026
Features of the black hole interior can be extracted from the analytic structure of boundary correlation functions. Working in the geodesic approximation, we find analytic continuations that probe the interior of rotating and charged black holes. These generate contributions from timelike geodesics that thread the interior and emerge in a future universe. We implement these continuations on the momentum space two-point function and exemplify this in several black hole backgrounds. We also identify position space analytic continuations achieving the same task that incorporate different continued momentum space correlators. These correspond to non-perturbative corrections to the WKB approximation. We demonstrate this explicitly in the rotating BTZ black hole by showing that the interior geodesics contribute to the continued position space correlator and motivate a picture for how these contributions arise in higher dimensions. For AdS Schwarzschild, we identify the analytically continued solution that captures the bouncing geodesic. We discuss the possibility of using these continuations to probe the instability of inner horizons from the boundary.
Clifford V. Johnson (University of California, Santa Barbara) | Universal Formulae for a Large Class of Correlators | April 3, 2026
A new and strikingly simple procedure for deriving universal formulae for correlation functions in a broad class of models is presented. Physics applications include double-scaled random matrix models, low-dimensional models of gravity and supergravity, various string theories, and the low-temperature, near-horizon quantum dynamics certain black holes. Mathematical applications include computations in intersection theory on the compactified moduli space of (super)Riemann surfaces of genus g and n boundaries, as well as evaluations of its volume. In certain supersymmetric cases, the techniques used provide swift derivations of some remarkable closed-form formulae from the mathematical literature, and readily yield new closed-form expressions.
Al Shapere (UKentucky) | Ensemble holography, topological gravity, and codes | March 27, 2026
In recent years, a number of examples of bulk gravitational theories have arisen whose boundary duals are not individual quantum field theories but ensembles thereof. By considering some exactly solvable examples of ensemble holography, I will address two questions: When does an ensemble of CFTs have a bulk dual? When is a topological field theory, summed over a given set of topologies, dual to an ensemble of boundary CFTs? The answers to both questions will turn out to be governed by codes.
Xi Yin (Harvard) | Revisiting Matrix String Theory | March 20, 2026
I will revisit matrix string theory as a possibly non-perturbative formulation of the superstring S-matrix, and discuss its implications and tests.
Jakob Moritz (University of Wisconsin) | The String Landscape, precisely | February 27, 2026
Compactifications of higher dimensional string theories offer perhaps the most promising ``top-down’’ path toward realistic models of our universe. In the way stands the notorious difficulty of computing the 4d effective action beyond tree level, and a lack of concrete embeddings of Standard Model-like physics with a sufficiently long lived vacuum. In this talk, after reviewing the current status of such compactifications (the “string landscape”), I will present recent and ongoing works aimed at these problems. Concretely, I will discuss work on string dualities that can be used as a tool to evaluate certain quantum corrections in flux compactifications, as well as upcoming work featuring new ensembles of top-down Standard Model constructions using type IIB string theory. Finally, I’ll report on progress in evaluating the classical superpotential in type IIB compactifications on Calabi-Yau orientifolds.
Based on works with Federico Compagnin, Jim Halverson, Björn Hassfeld, and Elijah Sheridan
Ian Moult (Yale) | Energy Correlators in Particle Physics, QFT and Gravity | January 30, 2026
Detector operators, of which the average null energy operator provides the most famous example, arise as direct theoretical models of asymptotic measurements in collider experiments. In QFT, detector operators are expressed in terms of "light-ray operators", whose correlation functions provide an interesting class of non-perturbatively well-defined observables.
In this talk, I will give an overview of light-ray/ detector operators, and attempt highlight the different perspectives and motivations for studying these operators, coming from the CFT, amplitudes and phenomenological communities. I will then present recent measurements of these correlators in experiment, as well as applications to positivity bounds on OPE coefficients.
Liam Fitzpatrick (Boston U) | CFT Data, QFT RG Flows, and the Fuzzy Sphere | January 23, 2026
The CFT data -- scaling dimensions and OPE coefficients -- of high dimension operators contains valuable information about the theory and its deformations, but is traditionally unobtainable outside of integrable models. We will review how the fuzzy sphere regulator allows numeric access to much of this data in the 3d Ising model, and show how to exploit the emergent conformal generators of the theory to significantly improve it. We discuss some of the applications of this data, including tests of the Eigenstate Thermalization Hypothesis and the spectrum of masses of the QFTs in the vicinity of the critical point.
Anshuman Maharana (UM) | High Frequency Gravitational Waves & Strings | January 16, 2026
High frequency gravitational waves are likely to become an important observable in cosmology and high energy physics.After briefly discussing the stochastic gravitational wave background predicted by the standard model of particle physics (and cosmology),I will discuss the high frequency gravitational waves from an early universe in a hagedorn phase. Related aspects of string thermodynamics and flux compactification will also be discussed.
