**Monday, February 18, 2019**

High Energy Theory Seminar

“Hamiltonian truncation and the $S^3$ partition function”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 2:30 PM

Speaker(s): Matthijs Hogervorst, Perimeter Institute**Description:**In this talk I discuss Hamiltonian truncation, a toolkit to construct quantum field theories. Hamiltonian truncation is in many ways orthogonal to the more familiar lattice regularization, and it can be used to systematically compute QFT observables with little computational effort. In the first part of this talk I will review the basic ideas behind this method, as well as some examples from the literature in d=2 and d>2 dimensions. In the second part I will discuss recent work involving strongly-coupled scalar theories on the three-dimensional sphere. Based on hep-th/1811.00528.

**Tuesday, February 19, 2019**

Pheno & Vino Seminar

“Dark Matter Strikes Back at the Galactic Center”

Location: Jadwin Hall, Room 303

Time: 4:00 PM

Speaker(s): Rebecca Leane, MIT**Description:**The Galactic Center GeV Excess (GCE) is firmly detected. While there is statistical evidence suggesting the excess originates largely from point sources, its interpretation as a signal of annihilating dark matter has not been conclusively ruled out. In this talk, I will examine the impact of unmodelled source populations on identifying the true origin of the GCE, using non-Poissonian template fitting (NPTF) methods. In a simulated proof-of-principle scenario, I will show that unmodelled sources in the Fermi Bubbles leads to a dark matter signal being misattributed to point sources by the NPTF. Strikingly, we find there is behavior consistent with such an effect in the real Fermi data, as a fake injected dark matter signal is completely misattributed to point sources. This demonstrates that dark matter may be substantially contributing to the GCE, as its presence can be incorrectly discarded due to a yet discovered unmodelled point source population biasing results.cted. While there is statistical evidence suggesting the excess originates largely from point sources, its interpretation as a signal of annihilating dark matter has not been conclusively ruled out. In this talk, I will examine the impact of unmodelled source populations on identifying the true origin of the GCE, using non-Poissonian template fitting (NPTF) methods. In a simulated proof-of-principle scenario, I will show that unmodelled sources in the Fermi Bubbles leads to a dark matter signal being misattributed to point sources by the NPTF. Strikingly, we find there is behavior consistent with such an effect in the real Fermi data, as a fake injected dark matter signal is completely misattributed to point sources. This demonstrates that dark matter may be substantially contributing to the GCE, as its presence can be incorrectly discarded due to a yet discovered unmodelled point source population biasing results.

**Wednesday, February 20, 2019**

Physics Group Meeting

“Formation of compact structures with axion dark matter”

Location: Bloomberg Hall Physics Library

Time: 1:45 PM

Speaker(s): Ken Van Tilburg, Member, School of Natural Sciences, IAS; New York University**Description:**Light scalar dark matter fields can exhibit several interesting aspects to their cosmological evolution. I will focus mostly on structure formation with ultralight axions and with the QCD axion. The standard scenario leads to a*suppression*of structure on small scales. I will show that there can also be an*enhancement*of power just below the scale of suppression. This effect will lead to the formation of compact axion halos, with broad implications for their observational prospects.**Reading list**

Cosmology reviews for:-- ultralight axions (Marsh): https://arxiv.org/abs/1510.07633

-- QCD axion (Wantz & Shellard): https://arxiv.org/abs/0910.1066

First mentions of the enhanced structure effect:

-- by Zhang & Chiueh https://arxiv.org/abs/1702.07065

-- by Cedeno et al https://arxiv.org/abs/1703.10180

**Thursday, February 21, 2019**

Hamilton Colloquium Series

“Statistical Physics of Computational Problems”

Location: Jadwin Hall, Room A10

Time: 4:00 PM

Speaker(s): Lenka Zdeborova, Institute of Theoretical Physics in CEA Saclay, France**Description:**What are the problems we can solve using a computer? is one of the very fundamental question in science. We will describe how do we use statistical physics to address this question. We will discuss what insights does physics bring to the field of algorithmic hardness and how is this insight used to develop better algorithms. We will describe examples of applications in artificial neural networks, compressed sensing or data clustering.

**Friday, February 22, 2019**

High Energy Theory Seminar

“Bridging the gap between lattice models and TQFT”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): Michael Levin, University of Chicago**Description:**Every (2+1) dimensional lattice model with an energy gap is believed to be described by a topological quantum field theory (TQFT) in the low energy, long wavelength limit. What this means concretely is that every lattice model of this kind is associated with a collection of universal topological data that defines the corresponding TQFT. Physically, this data describes the statistical phases associated with braiding or fusing particle-like excitations of the model. Some of these statistical phases, however, are missing a precise definition that would allow for their computation from a microscopic Hamiltonian. In this talk, I will address this issue by giving a microscopic definition of the F-symbol --- one of the most poorly understood pieces of data that characterize TQFTs. I will also discuss applications of this definition to the computation of anomalies in (1+1) dimensional field theories and lattice models.

**Monday, February 25, 2019**

High Energy Theory Seminar

“Twisted holography for the N=4 chiral algebra”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Kevin Costello, Perimeter Institute**Description:**Beem et al. used a superconformal supercharge to localize N=4 Yang-Mills to a two-dimensional chiral theory. I will discuss my work with Gaiotto, in which we analyze the holographic dual of this localization. We argue that the same localization applied to type IIB string theory yields a topological string living on AdS_3 x S^3. We build a holographic chiral algebra using Witten diagrams for this topological string theory, and show that the holographic chiral algebra is isomorphic to the large N chiral algebra in the planar limit.

**Wednesday, February 27, 2019**

Physics Group Meeting

“TBA”

Location: Bloomberg Hall Physics Library

Time: 1:45 PM

Speaker(s): Yvonne Geyer, Member, School of Natural Sciences, IAS; New York University

**Thursday, February 28, 2019**

Hamilton Colloquium Series

“Why I don't believe that Quantum Mechanics is the Whole Truth”

Location: Jadwin Hall, Room A10

Time: 4:00 PM

Speaker(s): Anthony Leggett, University of Illinois**Description:**Not long after the birth of quantum mechanics nearly a century ago, Erwin Schroedinger pointed out, in his famous "Cat" paper, the difficulty which arises if we assume that the theory gives a complete account of the world up to and including our observations of it. This difficulty, known as the measurement, or better realization, problem, has generated thousands of papers in the literature which claim to have resolved it. In this talk I will first explain why I do not believe that any of these "solutions" is satisfactory, and secondly review the progress which has been made over the last two decades in setting constraints on a possible breakdown of the quantum description as we progress from the microscopic level to that of our everyday experience.

**Friday, March 1, 2019**

High Energy Theory Seminar

“TBA”

Location: Jadwin Hall, PCTS Seminar Room

Time: 1:45 PM

Speaker(s): Zohar Komargodski, Stony Brook University**Description:**

**Monday, March 4, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Samir Mathur, Ohio State University**Description:**

**Tuesday, March 5, 2019**

Pheno & Vino Seminar

“TBA”

Location: Jadwin Hall, Room 303

Time: 4:00 PM

Speaker(s): Kim Boddy, Johns Hopkins University

**Wednesday, March 6, 2019**

Princeton Gravity Initiative

“The Gravity Initiative Inaugural Meeting”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 9:00 AM

**Description:****The Princeton Gravity Initiative**was founded to elevate local research exploring the mysteries of gravity across the disciplines of mathematics, physics and astrophysics. Our*inaugural conference*celebrates this theme, bringing together leading experts from nearby institutions, and highlighting the work of the next generation of young researchers at Princeton.Register here: https://goo.gl/forms/ILyPvlZbrq6wAY6j1

https://gravity.princeton.edu/events/gravity-initiative-inaugural-meeting

**Thursday, March 7, 2019**

Princeton Gravity Initiative

“The Gravity Initiative Inaugural Meeting”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 9:00 AM

**Description:****The Princeton Gravity Initiative**was founded to elevate local research exploring the mysteries of gravity across the disciplines of mathematics, physics and astrophysics. Our*inaugural conference*celebrates this theme, bringing together leading experts from nearby institutions, and highlighting the work of the next generation of young researchers at Princeton.Register here: https://goo.gl/forms/ILyPvlZbrq6wAY6j1

https://gravity.princeton.edu/events/gravity-initiative-inaugural-meeting

**Friday, March 8, 2019**

Princeton Gravity Initiative

“The Gravity Initiative Inaugural Meeting”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 9:00 AM

**Description:****The Princeton Gravity Initiative**was founded to elevate local research exploring the mysteries of gravity across the disciplines of mathematics, physics and astrophysics. Our*inaugural conference*celebrates this theme, bringing together leading experts from nearby institutions, and highlighting the work of the next generation of young researchers at Princeton.Register here: https://goo.gl/forms/ILyPvlZbrq6wAY6j1

https://gravity.princeton.edu/events/gravity-initiative-inaugural-meeting

**Thursday, March 14, 2019**

PCTS Conference

“CFT Perspectives on Thermalization and Chaos”

Location: PCTS Seminar Room, Jadwin Hall, Room 407

Time: 8:30 AM

**Description:**Program Organizers: Tolya Dymarsky, Tom Faulkner, Xiaoliang Qi, Herman VerlindeThe topics of non-equilibrium quantum physics and quantum chaotic dynamics are currently playing a central role in many areas of physics, from the attempt to understand quantum gravity in the bulk, to the emergence of anomalous transport in various condensed matter systems. The goal of the workshop is to address these questions from the point of view of conformal field theories, which provide a natural relevant theoretical framework. This conference will bring together a group of experts working on various aspects of CFTs ranging from the large central charge limit in two dimensions, to Eigenstate Thermalization Hypothesis, to higher-dimensional bootstrap at finite temperature, and beyond.

Registerhere:https://docs.google.com/forms/d/e/1FAIpQLScU1HQMBJ3u2IcIZbgkTySFgxPxIuANPff8IAdsBpPt53NpNQ/viewform

**Friday, March 15, 2019**

PCTS Conference

“CFT Perspectives on Thermalization and Chaos”

Location: PCTS Seminar Room, Jadwin Hall, Room 407

Time: 8:30 AM

**Description:**Program Organizers: Tolya Dymarsky, Tom Faulkner, Xiaoliang Qi, Herman VerlindeThe topics of non-equilibrium quantum physics and quantum chaotic dynamics are currently playing a central role in many areas of physics, from the attempt to understand quantum gravity in the bulk, to the emergence of anomalous transport in various condensed matter systems. The goal of the workshop is to address these questions from the point of view of conformal field theories, which provide a natural relevant theoretical framework. This conference will bring together a group of experts working on various aspects of CFTs ranging from the large central charge limit in two dimensions, to Eigenstate Thermalization Hypothesis, to higher-dimensional bootstrap at finite temperature, and beyond.

Registerhere:https://docs.google.com/forms/d/e/1FAIpQLScU1HQMBJ3u2IcIZbgkTySFgxPxIuANPff8IAdsBpPt53NpNQ/viewform

**Saturday, March 16, 2019**

PCTS Conference

“CFT Perspectives on Thermalization and Chaos”

Location: PCTS Seminar Room, Jadwin Hall, Room 407

Time: 8:30 AM

**Description:**Program Organizers: Tolya Dymarsky, Tom Faulkner, Xiaoliang Qi, Herman VerlindeThe topics of non-equilibrium quantum physics and quantum chaotic dynamics are currently playing a central role in many areas of physics, from the attempt to understand quantum gravity in the bulk, to the emergence of anomalous transport in various condensed matter systems. The goal of the workshop is to address these questions from the point of view of conformal field theories, which provide a natural relevant theoretical framework. This conference will bring together a group of experts working on various aspects of CFTs ranging from the large central charge limit in two dimensions, to Eigenstate Thermalization Hypothesis, to higher-dimensional bootstrap at finite temperature, and beyond.

Registerhere:https://docs.google.com/forms/d/e/1FAIpQLScU1HQMBJ3u2IcIZbgkTySFgxPxIuANPff8IAdsBpPt53NpNQ/viewform

**Monday, March 18, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Mihalis Dafermos, Princeton University**Description:**

**Wednesday, March 20, 2019**

Physics Group Meeting

“TBA”

Location: Bloomberg Hall Physics Library

Time: 1:45 PM

Speaker(s): Douglas Stanford, Member, School of Natural Sciences, IAS

**Friday, March 22, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): Douglas Stanford, Member, School of Natural Sciences, IAS**Description:**

**Monday, March 25, 2019**

High Energy Theory Seminar

“TBA”

Location: TBA

Time: 2:30 PM

Speaker(s): Scott Collier, Harvard University

**Friday, March 29, 2019**

High Energy Theory Seminar

“TBA”

Location: Jadwin Hall, PCTS Seminar Room

Time: 1:45 PM

Speaker(s): Xinan Zhou, Princeton University

**Monday, April 1, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Liam McAllister, Cornell University**Description:**

**Friday, April 5, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): TBA

**Monday, April 8, 2019**

High Energy Theory Seminar

“TBA”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 2:30 PM

Speaker(s): Fridrik Gautason, KU Leuven

**Wednesday, April 10, 2019**

Princeton Gravity Initiative Spring Conference

“Weak Gravity and Cosmic Censorship: Conjectures and Connections”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 10:00 AM

**Description:****Speakers**:**Oscar Campos Dias**, University of Southampton,**Mihalis Dafermos**, Princeton;**Frederick Denef**, Columbia;**Isabel Garcia Garcia**, UCSB;**Daniel Harlow**(to be confirmed)**,**MIT;**Gary Horowitz**, UCSB;**Jonathan****Luk**, Stanford;**Hirosi Ooguri**, CALTECH;**Matt Reece**, Harvard;**Tom Rudelius**, IAS;**Timm Wrase**, ITP.**Program Organizers**: Herman Verlinde and Netta Engelhardt**This workshop is being co-hosted by PCTS.**Please visit website to register.

**Thursday, April 11, 2019**

Princeton Gravity Initiative Spring Conference

“Weak Gravity and Cosmic Censorship: Conjectures and Connections”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 10:00 AM

**Description:****Speakers**:**Oscar Campos Dias**, University of Southampton,**Mihalis Dafermos**, Princeton;**Frederick Denef**, Columbia;**Isabel Garcia Garcia**, UCSB;**Daniel Harlow**(to be confirmed)**,**MIT;**Gary Horowitz**, UCSB;**Jonathan****Luk**, Stanford;**Hirosi Ooguri**, CALTECH;**Matt Reece**, Harvard;**Tom Rudelius**, IAS;**Timm Wrase**, ITP.**Program Organizers**: Herman Verlinde and Netta Engelhardt**This workshop is being co-hosted by PCTS.**Please visit website to register.

**Friday, April 12, 2019**

Princeton Gravity Initiative Spring Conference

“Weak Gravity and Cosmic Censorship: Conjectures and Connections”

Location: Jadwin Hall, PCTS Seminar Room, 4th Floor

Time: 10:00 AM

**Description:****Speakers**:**Oscar Campos Dias**, University of Southampton,**Mihalis Dafermos**, Princeton;**Frederick Denef**, Columbia;**Isabel Garcia Garcia**, UCSB;**Daniel Harlow**(to be confirmed)**,**MIT;**Gary Horowitz**, UCSB;**Jonathan****Luk**, Stanford;**Hirosi Ooguri**, CALTECH;**Matt Reece**, Harvard;**Tom Rudelius**, IAS;**Timm Wrase**, ITP.**Program Organizers**: Herman Verlinde and Netta Engelhardt**This workshop is being co-hosted by PCTS.**Please visit website to register.

**Friday, April 12, 2019**

High Energy Theory Seminar

“TBA”

Location: TBA

Time: 1:45 PM

Speaker(s): Nathan Benjamin, Princeton University

**Monday, April 15, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Alexandre Streicher, University of California, Santa Barbara**Description:**

**Friday, April 19, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): TBA

**Monday, April 29, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): TBA

**Friday, May 3, 2019**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): TBA