In conformal field theory, in contrast to gapped theories, S-matrix is not well-defined. Similarly, various inclusive observables which make sense in a gapped theory, such as "energy squared" calorimeters, suffer from IR divergences in CFTs.

# Events Archive

## 2020

### HET Seminar | Petr Kravchuk, Member, School of Natural Sciences, IAS | “Light-rays and detectors in Wilson-Fisher theory” | via Zoom

### Gravity Group Seminar | Meet the Gravity Group

We will kick off this season with a "Meet the Gravity Group" event. The format will be the same as last year's: all of us, be we juniors getting started on our Fall papers or emeritus, will get one slide and one minute to introduce ourselves to our new colleagues and share our spring / summer updates with the group.

### HET Seminar | Zohar Komargodski, Simons Center for Geometry and Physics, Stony Brook University | “Non-Symmetries, Naturalness, and Two-Dimensional Adjoint QCD” | via Zoom

We will explain the notion of "non-symmetries" or "defect symmetries." We will show that massless two-dimensional QCD admits exponentially many such symmetries. We will use them to prove deconfinement as well as to compute exactly the tension of all k-strings in the small mass limit.

### PGI Virtual Seminar Series | Alex Lupsasca, "The Shape of the Black Hole Photon Ring: A Precise Test of Strong-Field General Relativity"

We propose a new test of strong-field general relativity (GR) based on the universal interferometric signature of the black hole photon ring. The photon ring is a narrow ring-shaped feature, predicted by GR but not yet observed, that appears on images of sources near a black hole.

### Biophysics Seminar: Bill Bialek & Josh Shaevitz, Princeton University: State of the Center| Zoom

### FPO - Laura Chang - Dark Matter in the Milky Way

We have entered a data-driven era of astrophysics and cosmology, providing a wealth of datasets within which to search for the answers to some of the most fundamental open questions in the physics of our Universe.

### FPO - Kelvin Mei - "A Search for Scalar Top Quarks in Final States with High Jet Multiplicity and a Lepton with the CMS detector at the Large Hadron Collider"

A search is conducted for scalar top quarks decaying in the Full Run II dataset for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) of 137.2\fbinv collected at a center of mass energy of √s = 14 TeV.

### HET Seminar | Lorenz Eberhardt, Member, School of Natural Sciences, Institute for Advanced Study | “Partition functions of the tensionless string” | via Zoom

I discuss string theory on AdS3xS3xT4 in the tensionless limit, with one unit of NS-NS flux. This theory is conjectured to be dual to the symmetric product orbifold CFT.

### FPO - Tong Gao - Thermal Transport Properties of Quantum Spin Liquid Materials

Abstract Quantum spin liquids(QSL) have fascinated physicists for nearly half a century since Anderson first introduced this concept with his resonating-valence-bond(RVB) idea in 1973. Although many progresses had been made, more challenges emerge from both theoretical and experimental perspectives.

### FPO - JaeUk Kim - Hyperuniformity of Point Patterns and Two-Phase Composite Media

This dissertation focuses on the generation of certain special disordered systems, as well as general tools that have been developed to characterize their microstructures. Particular attention is devoted to disordered hyperuniform systems, which are ex- otic amorphous states of matter that lie between crystals and liquids.

### FPO - Zheng Ma - "Generation and Structural Characterization of Non-Hyperuniform and Hyperuniform Disordered Systems"

This dissertation focuses on the generation of certain special disordered systems, as well as general tools that have been developed to characterize their microstructures. Particular attention is devoted to disordered hyperuniform systems, which are ex- otic amorphous states of matter that lie between crystals and liquids.

### HET Seminar | Andy Neitzke, Yale University | “An update on exact WKB and supersymmetric field theory” | via Zoom

Over the last decade it has become clear that there is a close connection between the BPS sector of N=2 supersymmetric field theories in four dimensions and the exact WKB method for analysis of ordinary differential equations (Schrodinger equations and their higher-order analogues).

### HET Seminar | Leopoldo A. Pando Zayas, University of Michigan, Ann Arbor | "Sub-leading microstate counting of AdS black hole entropy" | via Zoom

I will briefly describe some recent progress in the microscopic understanding of the entropy of certain AdS black holes.

### HET Seminar | Xi Dong, University of California, Santa Barbara | "Enhanced Corrections to the Page Curve near Holographic Entanglement Transitions” | via Zoom

I will present enhanced corrections to the entanglement entropy of a subsystem in holographic states. These corrections appear near phase transitions in the entanglement entropy due to competing extremal surfaces, and they are holographic avatars of similar corrections previously found in chaotic energy eigenstates. I will first show...

### HET Seminar | Ken Van Tilburg, University of California, Santa Barbara | “Stellar Basins of Gravitationally Bound Particles” | via Zoom

I will describe and explore the consequences of a newly identified physical phenomenon: volumetric stellar emission into gravitationally bound orbits of weakly coupled particles such as axions, moduli, hidden photons, and neutrinos.

### Virtual Condensed Matter Seminar | Yuan Cao, MIT | "Competing Orders, Nematicity and Novel Josephson Effects in Superconducting Graphene Superlattices"

The emergence of two-dimensional materials have provided physicists with unprecedented way of studying the motion of electrons in a superconductor. Although superconductivity itself has been studied for more than a century, the recent advances of “twistronics” research in graphene superlattices brings fundamentally new physics into the picture...

### FPO - Jiaqi Jiang "Selected problems in quantum field theory in different dimensions"

### FPO - Alexey Milekhin - "Quantum mechanical systems with holographic duals"

This thesis is devoted to studying quantum mechanical systems with gravity duals. It is interesting to study holographic correspondence for quantum mechanical systems since we have much more theoretical control over them compared to quantum field theories.

### FPO - Justin Ripley - "General relativity and its classical modification in gravitational collapse"

In this thesis, we describe numerical spherical collapse solutions to a ``modified gravity'' theory, Einstein dilaton Gauss-Bonnet (EdGB) gravity.

### FPO - Jingjing Lin "Transport Properties of Topological Chalcogenides under Pressure"

Magnetic breakdown refers to the tunneling of electrons between distinct orbitals beyond a critical magnetic field.