Quantum field theories can have ordinary global symmetries, as well as generalized higher-form symmetries. 2-group symmetries arise when a generalized 1-form symmetry mixes with ordinary global symmetries. I will discuss theories with continuous 2-group symmetries in four and six spacetime dimensions.

# Events Archive

## 2018

### HET Seminar | Thomas Dumitrescu, Harvard | “Fun with 2-Group Global Symmetries” | PCTS Seminar Room

### Condensed Matter Seminar | Dan Shahar, Weizmann Inst. | "Hot superconductors and cold insulators” | PCTS Seminar Room 407

Abstract:

### Biophysics Seminar: William Bialek, Princeton U. "Statistical mechanics for networks of real neurons"

*Please join us at 12 noon for lunch, seminar from 12:15-1:15.*

### HET Seminar at IAS | Shu-Heng Shao, Member, School of Natural Sciences, IAS | “Beyond Symmetry: Topological Defect Lines and RG Flows in Two Dimensions”

Global symmetries in two dimensions are implemented by topological defect lines (TDLs). For continuous global symmetries, the TDLs are nothing but the Noether charges. However, there are TDLs that are not associated to any global symmetry, and can be thought of as a generalized notion of symmetry.

### Pheno & Vino Seminar | Zackaria Chacko, UMD, | "Cosmological Signatures of a Mirror Twin Higgs" | Jadwin 303

Abstract: I explore the cosmological signatures associated with the twin baryons, electrons, photons and neutrinos in the Mirror Twin Higgs framework.

### Informal HET Seminar at IAS | Markus Luty, UC Davis | “A Positive Sum Rule for the c Anomaly in 4D CFT”

### HET Seminar at IAS | Kemal Gokce Basar, UIllinois Chicago | “Going with the Flow: A Solution to the Sign Problem”

I will explore the generalization of the Feynman path integral in quantum field theory to complexified fields, and explain how it can be utilized to tackle the famous "sign problem". The sign problem prevents first principle studies of real-time dynamics and finite density systems via lattice field theory and appears in many different areas in...

### HET Seminar | Shai Chester, Princeton | "AdS_4/CFT_3 beyond supergravity" | PCTS Seminar Room

The paradigmatic example of AdS_4/CFT_3 relates M-theory on AdS_4 x S^7 to the family of maximally supersymmetric 3d CFTs discovered by Aharony, Bergman, Jafferis, and Maldacena (ABJM). I will focus on the stress tensor four point function for these dual theories.

### Gravity Group Lunch Seminar, Yaqiong Li | Joseph van der List (Princeton University)

**Yaqiong Li, Princeton University**

"The Microwave SQUID Multiplexing System in CMB Receivers"

### Hamilton Colloquium Series: Pablo Jarillo-Herrero, MIT; “Magic Angle Graphene: a New Platform for Strongly Correlated Physics”

The understanding of strongly correlated quantum matter has challenged physicists for decades. Such difficulties have stimulated new research paradigms, such as ultra-cold atom lattices for simulating quantum materials. In this talk I will present a new platform to investigate strongly correlated physics, based on graphene moiré superlattices...

### HEP Seminar -Isobel Ojalvo-Princeton-"The Tau Lepton as a Tool for SM Physics at CMS"

This past year with data collected from the Large Hadron Collider (LHC) using the Compact Muon Solenoid experiment the first observation of the higgs in its decay to tau leptons with a single experiment was announced. Due to its very short lifetime, the tau lepton is normally only possible to detect in its decay to lighter leptons and mesons...

### HET Seminar at IAS | Douglas Stanford, Member, School of Natural Sciences, IAS | “A Tactical Retreat from the BH Information Problem”

In finite entropy systems such as black holes, real-time partition functions do not decay to zero at late times. It is a challenge to derive this non-decaying behavior starting from the path integral over the master fields of a large N theory.

### Pheno & Vino Seminar | Iftah Galon, Rugters U. | "Exploring dark sectors at FASER: ForwArd Search ExpeRiment at the LHC" | Jadwin 303

Abstract: New physics has traditionally been expected in the high-pT region at high-energy collider experiments.

### HET Seminar | Sylvain Carrozza, Perimeter Institute | "The large N melonic limit of O(N) tensor models" | PCTS Seminar Room

It has been recently recognized that the same type of melonic large N structure governs SYK models and tensor models alike. Following Witten and Klebanov-Tarnopolsky, this has led to the introduction of new SYK-like tensor models, which reproduce key features of SYK models in the familiar context of large N field theories.

### Biophysics Seminar: Ned Wingreen, Princeton

*Please join us at 12 noon for lunch, seminar from 12:15-1:15.*

### HET Seminar at IAS | Daniel Harlow, MIT | “Splittability and Noether's Theorem in Quantum Field Theory”

Noether's theorem is textbook material in quantum field theory, but among experts it has been known for a while that there are quantum field theories with continuous global symmetries which possess no conserved current. In this talk I will give a few examples of this, and also describe a relationship between this phenomenon and a general...

### Hamilton Colloquium Series: L. Mahadevan, Harvard University; "Motifs in morphogenesis"

How is living matter organized in space and time during multicellular morphogenesis? A comparative view across animals and plants suggests that the answer may lie in reusing just a few geometric and topological organ-sculpting motifs. Using examples, I will discuss the qualitative and quantitative basis for three of these motifs: elongation,...

### Pheno & Vino Seminar | Prateek Agrawal, Harvard | "The strong CP problem and UV instantons" | Jadwin 303

Abstract: The absence of sizeable CP violation in the strong sector is a long standing puzzle. A class of solutions to this problem rely on a global U(1) symmetry that is anomalous with QCD. These solutions lead to robust low-energy predictions, for example a massless up quark or a light axion.

### Special CM Seminar | Ruben Verresen, TUM & Max Planck |"The Topology and Quantum Criticality in 1+1D" | PCTS Seminar Room 407

Abstract: Ground states of gapped Hamiltonians can form 'symmetry-protected topological phases', characterized by zero-energy edge modes. We explore the quantum critical points between such topological phases in one spatial dimension.

### HET Seminar | Charles Rabideau, UPenn/Vrije Universiteit Brussel | "Holographic Entanglement and Poincare blocks in three-dimensional flat space" | PCTS Seminar Room

Inspired by a recent computation of holographic entanglement entropy in flat space holography, we proposed a covariant prescription to compute holographic entanglement entropy and Poincare blocks (Global BMS blocks) in the context of three-dimensional Einstein gravity in flat space.