During the semester we have a high energy seminar and a lunch seminar. In addition to these two seminars we participate in a joint theoretical high energy theory seminar in Newe Shalom. The joint seminar takes place on Tuesdays from 10:30 until 13:30 and includes two talks and lunch. This seminar is attended by the high energy groups of all the Israeli institutions and usually attracts a crowd of roughly twenty participants.

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` ` Sun Mon Tue Wed Thu Fri Sat Daniel Harlow 4:00 pm Daniel Harlow Dec 1 @ 4:00 pm – 5:00 pm Title: Global symmetry, Euclidean gravity, and the black hole information problemAbstract: In this talk I will show how the essential ingredients of recent calculations of the Page curve of an evaporating black hole can be usedto … Matthew Heydeman 4:00 pm Matthew Heydeman Dec 8 @ 4:00 pm – 5:00 pm Title: The Statistical Mechanics of Near-BPS Black HolesAbstract: The status of near extremal black holes in gravity and string theory has long remained unclear due to the failure of black hole thermodynamics at low temperatures. … Shahar Hadar 4:00 pm Shahar Hadar Dec 22 @ 4:00 pm – 5:00 pm Title: Photon Ring AutocorrelationsAbstract: In the presence of a black hole, light sources connect to observers along multiple paths. As a result, observed brightness fluctuations must be correlated across different times and positions in black hole images. … Soumyadeep Chaudhuri 4:00 pm Soumyadeep Chaudhuri Dec 29 @ 4:00 pm – 5:00 pm Title: Thermal order in large N conformal gauge theoriesAbstract: Our experience with many physical systems tells us that usually when a symmetry is spontaneously broken at low temperatures, it is restored upon increasing the temperature …

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Title: Global symmetry, Euclidean gravity, and the black hole information problem

Abstract: In this talk I will show how the essential ingredients of recent calculations of the Page curve of an evaporating black hole can be usedto generalize a recent argument against global symmetries beyond the AdS/CFT correspondence to more realistic theories of quantum gravity, illustrating a close connection between the absence of global symmetries and a unitary resolution of the black hole informationproblem. I’ll also give several low-dimensional examples of quantum gravity theories which do not have a unitary resolution of the black hole information problem, and which therefore can and do have global symmetries. Motivated by this discussion, I’ll conjecturethat in a certain sense Euclidean quantum gravity is equivalent to holography. Based on recent work with Edgar Shaghoulian.

In this talk, we will derive and solve an effective theory to describe 4D flat space black holes which are just above the BPS bound. This theory is an N=4 supersymmetric version of the 2D Jackiw-Teitelboim gravity <-> 1D Schwarzian correspondence which we will obtain from nearly AdS2xS2 black holes in 4D N=2 supergravity. Using the Schwarzian description of these low temperature black holes, we can compute the partition function and density of states exactly. Our results verify several conjectures about near-BPS black holes coming from string theory, including an exact extremal degeneracy agreeing with Bekenstein-Hawking and a thermodynamic mass gap between extremal and near-extremal black holes.

Title: Thermal order in large N conformal gauge theories

Abstract: Our experience with many physical systems tells us that usually when a symmetry is spontaneously broken at low temperatures, it is restored upon increasing the temperature sufficiently. The abundance of such systems raises the question of whether this is a universal feature of all quantum systems. In this talk, I will present examples of (3+1)-dimensional non-supersymmetric large N gauge theories which demonstrate violations of the above feature. I will argue that in the N tending to infinity limit, these theories have conformal manifolds which survive under all loop corrections to the beta functions of the couplings. I will show that under certain conditions, a subset of points on such a conformal manifold demonstrates the spontaneous breaking of a global symmetry at all nonzero temperatures. Furthermore, I will demonstrate that this symmetry breaking is accompanied by the Higgsing of a subset of gauge bosons leading the system to be in a persistent Brout-Englert-Higgs phase.

Title: Comments on holographic description of Narain theories.

Abstract: I will discuss to what extent holographic description of

Narain theories can mimic the conventional picture of large c

holography with weakly coupled gravity in the bulk. Namely is it

possible that the effective IR bulk theory consist of “$U(1)$

gravity” amended with some additional states. This picture leads to a

hypothesis that in the large central charge limit density of states of

any Narain theory would be bounded by below by that one of “$U(1)$

gravity.” This immediately implies maximal value of spectral gap of

primary fields is $Delta_1=c/(2pi e)$. In the rest of the talk I

will discuss self-consistency of this picture using quantum code and

chiral CFTs. First, I will show the proposed picture yields a new

bound on quantum stabilizer codes, which is compatible with previously

known bounds in the literature. Next, I will discuss variance of the

density of states, which for consistency, must be vanishingly small in

the large $c$ limit. I will consider ensembles of code and chiral

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Title: Frontiers in Positive Geometry.

Abstract: In this talk I will describe work in progress connecting scattering amplitudes to amplituhedra and positive geometries in kinematic space. For N=4 SYM in the planar limit, I will show how the geometry of the amplituhedron naturally provides a new approach to non-perturbative physics. I will also describe conjectural all-loop order, non-planar, non-supersymmetric amplituhedra for the tr(phi^3) theory–which are new (generally infinite) polytopes attached to any Riemann surface–and show how the connection to positive geometry forces the existence of “gravity” in this setting.

Title: Using Soft Hair to Dissolve the Firewall

Abstract: We build on the observation by Hawking, Perry and Strominger that a global black hole space-time supports a large number of soft hair degrees of freedom to shed new light on the firewall argument by Almheiri, Marolf, Polchinski, and Sully. The soft hair carries a sizable amount of entropy and is encoded in a transition function that connects the asymptotic and near horizon regions. We argue that an infalling observer automatically measures the classical value of the soft mode before reachingthe horizon and that this measurement implements a code subspace projection that enables the reconstruction of interior operators. We use the soft hair dynamics to introduce an observer dependent notion of the firewall and show that an infalling observer neverencounters a firewall before reaching the singularity.