Quantum Fields and Strings

This series consists of talks in the area of Quantum Fields and Strings.

Seminar Series Events/Videos

Currently there are no upcoming talks in this series.
 

 

Lundi fév 11, 2019
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Recently I pointed out that reconstruction of interior operators can be interpreted as the Hayden-Preskill recovery. Building on this observation, I will propose a resolution of the firewall puzzle by describing a state-independent reconstruction of interior operators which does not lead to the non-local signaling. 

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Jeudi fév 07, 2019

We show how the extended thermodynamics of hyperbolic black holes in AdS describes features of quantum information measures in quantum field theory, and discuss prospects for making further connections. In particular, the second law of thermodynamics is seen in this context to map to the generalized Zamolodchikov c-theorem, connecting these two firmly for the first time. Some projects for getting further lessons and perhaps new tools from  these connections (perhaps using holographic heat engines) are outlined. 

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Mardi oct 30, 2018
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We consider implications of superrotations as an asymptotic symmetry of asymptotically flat spacetimes.  Beginning with a review of the rich structure of interconnections between soft theorems, asymptotic symmetries, and                 memory effects, we describe the superrotation iteration.  The subleading soft graviton theorem can be cast as a Ward identity for this asymptotic symmetry in 4D, and also as one for the stress tensor of a putative CFT2.  We detail the change of scattering basis motivated by this asymptotic symmetry and discuss recent progress.

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Mardi oct 23, 2018
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In gauge theories, there is an inherent tension between locality and gauge invariance.   This is precisely expressed by the failure to factorize the physical Hilbert space into local tensor products.

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Mardi oct 16, 2018
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Abstract TBA

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Jeudi oct 11, 2018
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The two-point functions <O^n(x) Obar^n(y)> for generator O of Coulomb branch chiral rings in D=4 N=2 SCFT will be determined universally to all orders in 1/n by the theory's a-anomaly.
The calculation will be done using the method of large-charge expansion presented in [1706.05743]; the absence of F-terms in the (R-charge)^(-1) expansion of the effective action ensures this universality.
I will also comment on the non-universal and non-perturbative corrections to the two-point functions whose leading piece was numerically shown to go as O(exp(-sqrt(n))).  

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Mardi sep 18, 2018
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In this talk I will review the results of recent work in collaboration with  Cecilia De Fazio, Benjamin Doyon and István M. Szécsényi. We studied the entanglement of excited states consisting of a finite number of particle excitations. More precisely, we studied the difference between the entanglement entropy of such states and that of the ground state in a simple bi-partition of a quantum system, where both the size of the system and of the bi-partition are infinite, but their ratio is finite.

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Mardi sep 11, 2018
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In the context of the AdS(4)/BCFT(3) correspondence, we study the holographic entanglement entropy for spatial regions having arbitrary shape. An analytic expression for the subleading term with respect to the area law is discussed. When the bulk spacetime is a part of AdS(4),
this formula becomes the Willmore functional with a proper boundary term evaluated on the minimal surface viewed as a submanifold of the three dimensional flat Euclidean space with a boundary. 

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Vendredi juin 08, 2018

I will argue that in the context of string theory, the Big Bang singularity of standard and inflationary cosmology is automatically resolved. To see this at the level of an effective field theory, ideas from "Double Field Theory" are useful.

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Mardi juin 05, 2018
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I describe recent progress in classifying 5d N=1 field theories with interacting UV superconformal fixed points (i.e. 5d SCFTs). In the first part of the talk, I review a newly proposed catalog of candidate (simple) gauge theories which captures theories missed by prior field theoretic classification efforts. In the second part of the talk, I discuss a classification program for rank 1 and 2 5d SCFTs in terms of Calabi-Yau 3-folds, along with prospects for its extension to arbitrary rank.

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