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# General info

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Journal clubs are on Tuesdays from 13 to 14 in Seminar Room 3 (building = 1).

Feel free to suggest papers in the comments section. Note that you can a= lso add attachments and comment on other people's suggestions.

**Important: You need to login to see and add comments.**

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# Winter semester =
2019-2020

## Journal club 11-02-2020 (Integrability school)

Journal c= lub 28-01-2020 (TBA)

Journal c= lub 21-01-2020 (TBA)

## Journal club 10-12=
-2019

## Journal club 03-12=
-2019

## Journal club 26-11=
-2019

## Journal club 19-11=
-2019

## Journal club 12-11=
-2019

## Journal club 29-10=
-2019

## Journal club 22-10=
-2019

## Journal club 15-10=
-2019

# Summer 2019

## Journal club 08-10=
-2019

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Journal c= lub 28-01-2020 (TBA)

Journal c= lub 21-01-2020 (TBA)

- Fabrizio del Monte (SISSA), Class S theories and isomonodromic deformat=
ions on the torus.

Abstract:In the last f= ew years there have been many new results connecting (linear quiver) N=3D2 = class S theories, and the topological strings that engineeer them, to the t= heory of isomonodromic deformations on the sphere and their q-deformations.= These gauge theories are constructed by compactifying the 6d N=3D(0,2) SCF= T on a punctured Riemann Sphere, whose moduli, which are the marginal defor= mations of the gauge theory, are the times of the isomonodromic flows. The = aim of this talk is to show how this connection can be extended beyond the = case of genus zero, for more general (asymptotically superconformal) class = S theories. We will discuss in detail the case of circular quiver gauge the= ories, that are obtained from the N=3D(0,2) SCFT on punctured tori, and see= how the genus one case displays new qualitative features that are absent o= n the sphere, due to the possibility of various inequivalent vector bundles= , and how this actually provides new interesting relations satisfied by the= gauge theory partition function.

Jack Foster (Southampton University): Cluste= r Adjacency, Tropical Geometry, and Scattering Amplitudes

Abstract: I will discuss two new areas of inte= rest in scattering amplitudes: cluster adjacency and tropical geometry. The= former describes how the analytic structure of planar amplitudes in N=3D4 = Super Yang-Mills is controlled by mathematical objects called cluster algeb= ras. The latter has been used to calculate amplitudes in the biadjoint phi^= 3 theory, which I will discuss briefly, but it also has implications for cl= uster adjacency.

- Francesco Galvano (Torino): =
;Emitted radiation and geometry <=
/span>(This seminar will take place =
in
**Building 3 Seminar ro= om BAH 2**)&nbs= p;

Abstract: We discuss the computation of the radiated energ= y by an accelerated heavy particle. This quantity is captured by the one-po= int function of the stress energy tensor in presence of a Wilson line. In a= N=3D2 superconformal theory we prove that this observable is exactly relat= ed to a small geometric deformation of the background geometry. In a four d= imensional case, supersymmetric localization allows to express the emitted = energy in terms of a matrix model on a squashed sphere.

- No seminar scheduled.

- Zhengwen Liu: Scat=
tering Equations and Multi-Regge Kinematics

Abstract**:**The scattering equations, a system of alg= ebraic equations connecting the space of kinematic invariants and the modul= i space of punctured Riemann spheres, provide a novel w= ay to construct scattering amplitudes. In this framework, the tree-level S-= matrix in many quantum field theories can be reformulated as a multiple int= egral that is entirely localized on the zeroes of the scattering equations.= After presenting a very minimal introduction to the scattering equations, = I will discuss the asymptotic behavior of the scattering equations in the s= o-called Multi-Regge kinematic regime and the corresponding factorizations = of amplitudes in gauge theory and gravity.

References**:**Multi-Regge kinematics and the scattering equations<= /a>

Gravitationa= l Scattering in the High-Energy Limit

Journal club= 05-11-2019

- Yuta Sekiguchi (U. Bern, AEC), O(d,d) transformations preser=
ve classical integrability.
Abstract: We stud= ied the classical integrability of O(d,d) transformations including not onl= y O(d,d;Z) duality but also global O(d,d;R) deformation. The latter is know= n in the traditional literature to generate so-called current-current (JJba= r) deformations of 2D CFTs. In this talk, I first plan to give brief review= s Yang-Baxter deformations of string backgrounds as well as the doubled sig= ma model. Then I will present how to construct the Lax pairs in the O(d,d) = deformed WZNW models via O(d,d) map through very easy examples. The resulti= ng Lax connections are in general non-local because they depend on the wind= ing modes. Finally I will briefly comment on open questions under considera= tion in relation to the recent irrelevant integrable deformation. This talk= is based on the recent work [1907.03759] with Domenico Orlando, Susanne Re= ffert and Kentaroh Yoshida.

Till Bargheer: Exact Four-Point Functions: G= enus Expansion and Strong Coupling (This seminar will take place in

**= Building 3 Seminar room BAH 2**)

Using integrability, correlation functions of local = operators in planar N=3D4 super Yang-Mills theory can be computed by recons= tructing the dual worldsheet from a set of "hexagon" patches via "gluing" (= performing complete state sums over mirror Bethe states). After reviewing t= his general procedure, I will explain how it can be used to compute a certa= in class of four-point correlators as an exact function of the coupling at = any order in the 1/Nc genus expansion, and how the resulting series can be = re-summed (via a suitable matrix model) to recover the full Nc dependence. = If time permits, I will also comment on the strong-coupling limit of these = correlators.

Gleb Kotousov: "Reflection operators in inte= grable QFT".

Sylvain Lacroix, Gauge Theory And= Integrability, III (focusing on the second part about "disorder defect= s").

Alessandro Pini, Extremal Correla= tors and Random Matrix Theory.

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