Events Archive

IAS HET Seminar | Nissan Itzhaki, Tel Aviv University & IAS| “When Light Strings Don't Look Like Particles” | Bloomberg Lecture Hall & Zoom
Fri, Mar 17, 2023, 1:45 pm1:45 pm

In certain time-dependent backgrounds there are nonstandard light strings that are created classically at an instant and cannot be approximated by particles. We discuss the implications of these strings to black holes and cosmology.

IAS HET Seminar | Manki Kim, Massachusetts Institute of Technology| “Exponentially Small Cosmological Constants in String Theory” | Bloomberg Lecture Hall & Zoom
Mon, Mar 13, 2023, 2:30 pm2:30 pm

In this talk, I will describe recent progress on moduli stabilization in string theory. In particular, I will describe recently found supersymmetric AdS_4 vacua, with exponential scale separation, of type IIB string compactifications on O3/O7 orientifolds of Calabi-Yau threefolds.

HET Seminar |Simone Giombi, Princeton University| “ Holography on the AdS2 string and the Wilson line dCFT ” | PCTS & Zoom
Fri, Feb 24, 2023, 1:45 pm1:45 pm

In the gauge/string duality, Wilson loop operators are dual to
open string minimal surfaces anchored on the loop at the boundary of AdS.
In the simplest example, a circular Wilson loop corresponds
to an open string worldsheet with AdS2 geometry. The scattering amplitudes
of the worldsheet fluctuations are…

IAS HET Seminar | Jordan Cotler, Harvard University| “Isometric Evolution in de Sitter Quantum Gravity” | Bloomberg Lecture Hall (IAS) & Zoom
Thu, Feb 23, 2023, 1:45 pm1:45 pm

Do the postulates of quantum mechanics survive in quantum gravity?  The probabilistic interpretation of amplitudes, enforced by the unitarity of time evolution, is not guaranteed within the path integral formulation and has to be checked.  Leveraging the gravitational path integral, we find a non-perturbative mechanism whereby a sum…

HET Seminar |Giorgio Cipolloni , Princeton| “ How do the eigenvalues of a large non-Hermitian random matrix behave? ” | PCTS & Zoom
Mon, Feb 20, 2023, 2:30 pm2:30 pm

We prove that the fluctuations of the eigenvalues converge to the Gaussian Free Field (GFF) on the unit disk. These fluctuations appear on a non-natural scale, due to strong correlations between the eigenvalues.

Then, motivated by the long time behaviour of the ODE \dot{u}=Xu, we give a precise estimate on the eigenvalue with the…

IAS HET Seminar | Aaron Hillman, Princeton University| “Stringy Completions of the Standard Model from the Bottom Up” | Wolfensohn Hall & Zoom
Fri, Feb 17, 2023, 2:30 pm4:00 pm

We study a class of tree-level ansatzes for 2→2 scalar and gauge boson amplitudes inspired by stringy UV completions. These amplitudes manifest Regge boundedness and are exponentially soft for fixed-angle high energy scattering, but unitarity in the form of positive expandability of massive residues is a nontrivial consistency condition. …

IAS HET Seminar | Ashoke Sen, Harish-Chandra Research Institute, India| “D-instanton Amplitudes in String Theory” | Wolfensohn Hall & Zoom
Mon, Feb 13, 2023, 2:30 pm3:30 pm

 I shall review recent progress in computing D-instanton contribution to string theory amplitudes

HET Seminar |Kanato Goto , Princeton| “ How do wormholes emerge from the SYK model ” | Jadwin A09
Fri, Feb 10, 2023, 1:45 pm1:45 pm

Recent studies revealed that wormhole geometries play a central role in understanding quantum gravity. After disorder-averaging over random couplings, Sachdev-Ye-Kitaev (SYK) model has a collective field description of wormhole saddles. A recent paper by Saad, Shenker, Stanford, and Yao studied the SYK model with fixed couplings and found that…

HET Seminar |Zimo Sun, Princeton| “ Majorana Scars as Group Singlets ” | PCTS & Zoom
Mon, Feb 6, 2023, 2:30 pm2:30 pm

Based on the framework proposed in 2007.00845 and 2106.10300, we present a class of lattice models of Majorana fermions, that possess two sectors of many-body scar states.
These scar states, realized as group singlets of certain large rank group,  generalize the eta-pairing states and zeta states in Ferm-Hubbard model.

IAS HET Seminar | Yiming Chen, Princeton University| “Estimating Global Charge Violating Amplitudes from Wormholes” | Bloomberg Lecture Hall & Zoom
Fri, Feb 3, 2023, 1:45 pm1:45 pm

Global symmetries are expected to be violated in quantum gravity. The violation can be captured by nonzero scattering amplitudes with different initial and final global charges. In this talk, I will discuss such processes involving the scattering of high energy spherical shells in AdS spacetime. The focus will be to describe an explicit…

HET Seminar |Sanjay Moudgalya, Caltech| “ Unconventional Symmetries from Commutant Algebras ” | PCTS & Zoom
Mon, Jan 23, 2023, 2:30 pm2:30 pm

The study of symmetry lies at the heart of various parts of physics. In equilibrium physics, symmetries are useful in classifying phases of matter and in non-equilibrium physics, they are necessary to understand the phenomenon of thermalization. Most symmetries conventionally studied in the literature are examples of so-called on-site unitary…

IAS HET Seminar | Isabel Garcia Garcia, Institute for Advanced Study| “TBA” | Bloomberg Lecture Hall & Zoom
Fri, Dec 16, 2022, 1:45 pm1:45 pm
HET Seminar | Julien Barrat, Humboldt University of Berlin| “A dispersion relation for bootstrapping holographic defect correlators” | PCTS & Zoom
Tue, Nov 22, 2022, 2:00 pm2:00 pm

Tremendous progress has been achieved during the last years in bootstrapping conformal correlators at strong coupling using analytical bootstrap methods and the AdS/CFT correspondence. In particular, the development of Lorentzian inversion formulae revealed helpful in reconstructing four-point functions. In this talk I will present how this…

IAS HET Seminar | Sakura Schafer-Nameki, University of Oxford| “TBA” | Bloomberg Lecture Hall & Zoom
Mon, Nov 21, 2022, 2:30 pm2:30 pm
IAS HET Seminar | S. Josephine Suh, Member, School of Natural Sciences, IAS; Harvard University| “Spacetime and Gravity from Quantum Mechanics” | Bloomberg Lecture Hall & Zoom
Fri, Nov 18, 2022, 1:45 pm1:45 pm

Motivated by holographic duality and the Ryu-Takyanagi formula, we ask the question, “What quantum problem are Einstein’s equations solving?” Answering this question amounts to dissecting or “deconstructing” AdS/CFT to identify the quantum-mechanical origins of spacetime and gravity. We propose a solution involving a class of dynamical…

HET Seminar | Sabine Harribey, Nordita | “An application of melonic CFTs: The F-theorem” | PCTS & Zoom
Mon, Nov 14, 2022, 2:30 pm2:30 pm

Tensor models exhibit a melonic large-N limit. They were first introduced in zero dimension in the context of random geometry and quantum gravity. They were then generalized in d dimensions where they give rise in the infrared to a new kind of CFTs, analytically accessible, called melonic CFTs. In the first part of the talk, I will briefly…

IAS HET Seminar | Matteo Parisi, Institute for Advanced Study & Harvard University| “TBA” | Bloomberg Lecture Hall & Zoom
Fri, Nov 11, 2022, 1:45 pm1:45 pm
IAS HET Seminar |Masanori Hanada, University of Surrey| “TBA” | Bloomberg Lecture Hall & Zoom
Mon, Oct 31, 2022, 2:30 pm2:30 pm
IAS HET Seminar | Jonah Kudler-Flam, Institute for Advanced Study| “Quantum Information before the Page Time” | Bloomberg Lecture Hall & Zoom
Fri, Oct 21, 2022, 1:45 am1:45 pm

Radiation emitted from evaporating black holes is highly mixed, at least for times prior to the so-called "Page time." Usually, the quantum state of the radiation is then treated as void of information. I will discuss two ways in which this early time radiation contains non-trivial quantum information. First, I will characterize (in simple…