# Events Archive

High Energy Theory - Thomas Hartman, Cornell University - "Causality Constraints in Conformal Field Theory"
Mon, Dec 7, 2015, 2:30 pm3:30 pm
In effective field theory, causality fixes the signs of certain interactions. I will describe how these Lorentzian constraints are encoded in the Euclidean theory, and use the conformal bootstrap to derive analogous causality constraints in CFT. Applied to spinning fields, these constraints include (some of) the Hofman-Maldacena bounds derived…
High Energy Theory IAS - Jennifer Lin, IAS - “Bulk Energy Conditions from Relative Entropy and Comments on Bulk Reconstruction”
Fri, Dec 4, 2015, 1:45 pm3:00 pm
I will present results on how positivity properties of relative entropy in holographic CFT's give rise to energy conditions in asymptotically AdS spacetimes. This part will be a sequel to Nima Lashkari’s talk on 11/2. I will also comment on the status of reconstructing spacetime from entanglement in holography.

High Energy Theory IAS - Maurizio Pierini, CERN, “Signs of Hope: A Few LHC Run I Results to Watch for Run II”
Mon, Nov 30, 2015, 2:30 pm3:30 pm
During the first LHC long shutdown, the CMS collaboration finalised the study of the 8TeV data collected in 2012. Within the impressive amount of results produced, a few searches for new physics show a tension with the prediction from the Standard Model. While the significance is still too small to allow any conclusion, some of these excesses…
High Energy Theory - Agnese Bissi, Harvard University - "Superconformal blocks in N=4 SYM"
Mon, Nov 23, 2015, 2:30 pm3:30 pm
In this talk I will discuss how to find superconformal blocks associated to the four point function of half-BPS operators in N=4 SYM in 4 dimensions. I will discuss how to study this problem in the analytic superspace and I will conclude with some new developments and future directions.

High Energy Theory IAS - Xi Dong, IAS - “Entanglement, Spacetime, and Quantum Error Correction”
Fri, Nov 20, 2015, 1:45 pm3:00 pm
Over the last few years it has become clear that there is a deep connection between quantum entanglement and gravity. I will talk about two aspects of this connection. The first involves understanding quantum entanglement from a holographic perspective. In particular, I will propose a general formula for entanglement entropy in theories dual…
Physics Group Meeting - IAS - Discussion Group led by Christopher Beem, IAS - “Supersymmetric Operator Algebras”
Wed, Nov 18, 2015, 1:30 pm2:30 pm
We will discuss the various algebraic structures that appear when studying supersymmetric operators in SCFTs in various dimensions and the connections between them. For example, topics may include relatively standard constructions such as chiral rings, more recent constructions involving non-commutative associative algebras and chiral algebras…
High Energy Theory Special Seminar - Gabi Zafrir, Technion- Israel Inst. of Tech. - "Brane webs, 5d gauge theories and 6d N=(1,0) SCFT's"
Tue, Nov 17, 2015, 1:45 pm3:00 pm
Some 5d gauge theories have a 6d N=(1,0) SCFT as their UV completion. Given such 5d gauge theory we desire to determine its 6d UV completion. In this talk, I will present a method to do this for 5d gauge theories that can be engineered in string theory by brane webs. This can then be applied to study compactification of 6d N=(1,0) SCFT's on a…
High Energy Theory - Netta Engelhardt, UC, Santa Barbara - “New Area Law in General Relativity (and beyond)”
Mon, Nov 16, 2015, 2:30 pm3:30 pm
I will present a new area law in General Relativity. This new area law holds on local analogues of event horizons that have an independent thermodynamic significance due to the Bousso bound. I will also discuss a quantum generalization of this more local notion of thermodynamics.

High Energy Theory -Lorenzo Di Pietro, Weizmann Institute - “QED in d=3 from the epsilon-expansion”
Fri, Nov 13, 2015, 1:45 pm3:00 pm
I will consider the Renormalization Group flow of Quantum Electrodynamics in $d=3$ coupled to $N_f$ flavors of fermions. For $N_f$ smaller than a critical value $N_f^c$, chiral symmetry breaking is believed to take place. For $N_f > N_f^c$, the theory flows to an interacting fixed point that can be studied in the epsilon-expansion, using the…
Physics Group Meeting - IAS - Clay Cordova, IAS - “Aspects of BPS Particles”
Wed, Nov 11, 2015, 1:30 pm2:30 pm
I will review some properties of BPS particles in four-dimensional N=2 field theories. I will emphasize recent developments and unsolved problems including restrictions on the charges of BPS particles, ideas about their large charge degeneracies, and relationship to BPS operators. References: General background on BPS states http://arxiv.org
High Energy Theory - Andrea Puhm, UC Santa Barbara - "Black Hole Horizon Dynamics"
Mon, Nov 9, 2015, 2:30 pm3:30 pm
The claim that quantum gravity effects destroy the classical black hole horizon and has to be replaced by a firewall or horizon-scale structure is rather bold but is supported in string theory. I will discuss signs of this breakdown of effective field theory at the horizon of supersymmetric and Schwarzschild black holes and how the very…
Physics Group Meeting - IAS - Discussion Group led by Nathan Seiberg, IAS - “Anomalies, Conformal Manifolds, and Spheres”
Wed, Nov 4, 2015, 1:30 pm2:30 pm
We will discuss various aspects of the manifold of conformal field theories. Most of the time will be devoted to a review of older background material. It will allow us to give a unified and more conceptual treatment of some recent results. Background reading: H. Jockers, V. Kumar, J. M. Lapan, D. R. Morrison and M. Romo, “Two-Sphere…
High Energy Theory IAS - Nima Lashkari, MIT, “Gravity Dual of Relative Entropy”
Mon, Nov 2, 2015, 2:30 pm3:30 pm
Relative entropy is a measure of distinguishability of states and plays a central in quantum information theory. We argue that it is a natural generalization of free energy to far from equilibrium states. A generalization of the standard replica trick computes the relative entropy of arbitrary states in quantum field theory. We consider…
High Energy Theory - Piotr Surowka, Harvard University - "Anomalies, Geometry and Hydrodynamics"
Fri, Oct 30, 2015, 1:45 pm3:00 pm
I will show how hydrodynamics is modified if the underlying fluid constituents are massless Weyl fermions, which are anomalous at the quantum level. Because of the non-dissipative nature of the modification I will construct a partition function which compactly describes the transport properties of the system and I will explain how the anomalous…
Physics Group Meeting - IAS - Discussion group led by Raffaele D'Agnolo, Member, IAS - “The Second Run of the LHC”
Wed, Oct 28, 2015, 1:30 pm2:30 pm
After a short introduction for non-experts to the LHC experiments, we can talk about prospects for the next run. In its broadest form the question open for discussion is whether we expect to discover something in the next two to five years or not. Of course the question has both theoretical and experimental aspects. We will touch both and then…
High Energy Theory - James Sully, Stanford University - "Grammar lessons for holographers"
Mon, Oct 26, 2015, 2:30 pm3:30 pm
Understanding the language of holographic geometry is a difficult problem. I propose a useful set of tools to supplement our known bulk-to-boundary dictionary. These tools make use of kinematic space, an integral transform of the bulk geometry, and corresponding entropic probes in the boundary CFT. I will make connections to tensor network…
High Energy Theory IAS - Neil Turok, Perimeter Institute - “A Perfect Bounce”
Fri, Oct 23, 2015, 1:45 pm3:00 pm
We study the quantum cosmology of a universe with conformal matter. For homogeneous, isotropic metrics and matter, the quantum gravitational path integral may be performed exactly. The result is a "perfect bounce," in which the universe passes smoothly across the big bang singularity. We extend this treatment to include anisotropies and generic…
High Energy Theory IAS - David Kaplan, Johns Hopkins University, “A Cosmological Solution to the Hierarchy Problem”
Mon, Oct 19, 2015, 2:30 pm3:30 pm
I present a solution to the electroweak hierarchy problem which involves the relaxation of the Higgs mass in the early universe. I will briefly discuss the limits of validity of the model as well as potential experimental signatures.