AdS(Algeometry, duality and Strings) seminar
Student No.:40
Time:Thu 13:30-14:30, Aug.30-Jan.17
Instructor:Song Wei, Yan Wenbin, Lin Hai, Xu Jianfei, Sun Rui  
Place:Lecture Hall, Jin Chun Yuan West Building
Starting Date:2018-8-30
Ending Date:2019-1-17


Speaker: Zhihao Duan (ENS)

Title: Computing the elliptic genus of higher rank E strings from genus 0 GW invariants

In this talk, I will discuss the elliptic genera of BPS strings in 6d SCFTs. As we shall see, they are determined by a finite amount of data thanks to their modular property. Therefore, a crucial step is to impose suitable boundary conditions to fix them. Different from the vanishing conditions explored in arXiv: 1701.00764 and arXiv:1712.07017, we analyse the pole structure of the elliptic genera and reconstruct them using only their polar parts. The main goal of this talk is to show that the elliptic genus of higher rank E-strings can be computed based solely on the genus 0 Gromov-Witten invariants of the corresponding elliptic geometry. The talk is based on arXiv: 1810.01280.


Speaker: Jiahua Tian (Northeastern U)

Title: Non-simply-laced Symmetry Algebras in F-theory on Singular Spaces

We demonstrate how non-simply-laced gauge and flavor symmetries arise in F-theory on spaces with non-isolated singularities. The breaking from a simply-laced symmetry to one that is non-simply-laced is induced by Calabi-Yau complex structure deformation. In all examples the deformation maintains non-isolated singularities but is accompanied by a splitting of an I_1 sevenbrane that opens new loops in the geometry near a non-abelian seven-brane. The splitting also arises in the moduli space of a probe D3-brane, which upon traversing the new loop experiences a monodromy that acts on 3-7 string junctions on the singular space. The monodromy reduces the symmetry algebra, which is the flavor symmetry of the D3-brane and the gauge symmetry of the seven-brane, to one that is non-simply-laced. A collision of the D3-brane with the seven-brane gives rise to a 4d N = 1 SCFT with a non-simply-laced flavor symmetry.

2018-12-20, 11:45-13:00

Speaker: Si Li (YMSC, Tsinghua)

Title: Homotopy Algebras in Higher Spin Theory

Motivated by string field theory, we explain various algebraic aspects of higher spin theory and Vasiliev equation in terms of homotopy algebras. We present a systematic study of unfolded formulation developed for the higher spin equation in terms of the Maurer-Cartan equation associated to differential forms valued in L-infinity algebras. The elimination of auxiliary variables of Vasiliev equation is analyzed through homological perturbation theory. We also discover a topological quantum mechanics model whose correlation functions give deformed higher spin vertices at first order. This is joint work with Keyou Zeng.


Speaker: Alex Belin (University of Amsterdam)

Title: Holographic Symplectic forms and extremal volumes: a new York time story

In this talk, I will explain how the gravitational symplectic form between nearby AAdS geometries is dual to a quantum Kahler form on the space of euclidean path integral states with sources turned on. As an application, I will show that variations of extremal volumes can be computed using this symplectic form by considering a particular variation: the “new York” variation, which I will describe in detail. Finally, I will discuss the CFT interpretation of this deformation in some concrete examples like the vacuum and the TFD state at late times.


Speaker: Max Riegler (ULB)

Title: Warped Black Holes in Lower-Spin Gravity

In this talk I will talk about recent work (1801.07263) showing that (spacelike) warped AdS_3 black hole solutions can be consistently described in a lower-spin gravity theory. This model provides a very simple playground to explore warped black holes and at the same time warped conformal field theories at finite temperature. I will put an emphasis on the basic ideas that are needed to translate geometric statements into a gauge-theoretic language as well as how to compute the thermodynamic properties of warped black holes in this theory.


Speaker: Yiwen Pan(Zhongshan University)

Title: Fiber-base duality and 3d dualities

5d supersymmetric gauge theories often admit (p,q) web construction, and therefore enjoy the fiber-base duality which descends from the IIB S-duality. Such duality further leads to dualities in lower dimensional gauge theories. In this talk I will discuss simple examples where 5d fiber-base duality reduces to 3d mirror symmetry of gauge theories on intersecting spaces, and also possible connections to 3d-3d correspondence.


Speaker: Ioannis Papadimitroou (KIAS)

Title: SQFTs on curved backgrounds and supersymmetry anomalies

I will discuss a new quantum anomaly for rigid supersymmetry on even dimensional curved backgrounds that admit Killing spinors and will show how it is related to the superconfomal anomalies that are determined by the Wess-Zumino consistency conditions. I will then explore the implications of this anomaly for the dependence of supersymmetric partition functions on the geometric data of the background, for the supersymmetric Casimir energy, as well as for supersymmetric localization.


Speaker: Falk Hassler(U. of Oviedo)

Title: Poisson-Lie T-Duality in Double Field Theory

A formulation of Double Field Theory is presented which makes Poisson-Lie T-duality manifest. It allows to identify the doubled space with a Drinfeld double and provides a powerful tool to extract the transformation of the metric, B-field, dilaton and R/R potentials under Poisson-Lie T-duality.


Speaker: Prof. Dieter Luest (MPI for Physics & LMU Munich)

Title: Non-geometric fluxes and non-associativity in string/M-theory

In this talk I will discuss compactifications with geometric and non-geometric fluxes in string and in M-theory. These can be described by generalized geometry, double field theory and exceptional field theory. In particular I will discuss how non-geometric fluxes lead to a non-associative phase space structure, which is closely related to the non-associative algebra of the imaginary octonions.


Speaker: Andreas Braun (Oxford)

Title: What's new in G_2 ?

Compact manifolds with the exceptional holonomy groups G_2 and Spin(7) can be used in M-Theory to geometrically engineer theories in 4D and 3D with minimal supersymmetry. Building on new results in mathematics, we review recent progress in the construction of such geometries, the associated physics, and dualities to other string compactifications.


Speaker: Hossein Yavartanoo(ITP)

Title: H0 Tension & Swampland Conjectures

I will review some recent arguments on measuring Hubbell parameter and H0 tension. Further, borrowing from the string theory tool- kit, I will present a holographic model that relieves the tension and predicts a turning point in the Hubble parameter at small redshift. This feature is easily falsified by upcoming experiments, but is consistent with current data. I comment on the implications for the Swampland program.


Speaker: Yinan Wang(MIT)

Title: New constructions of Calabi-Yau manifolds from F-theory

In this talk, I'll present some new constructions of compact Calabi-Yau manifolds with elliptic fibration structure. In the framework of F-theory, different choices of Calabi-Yau manifolds will lead to different low energy physics after the compactification. First, I'm going to discuss the classification of elliptic Calabi-Yau threefolds, which corresponds to the classification of 6D (1,0) supergravity theories. Especially, I'm going to present a classification program of non-toric 2D base manifolds. Secondly, I'm going to talk about the geometry of elliptic Calabi-Yau fourfolds and some preliminary results of a classification program of toric 3D base manifolds. In the F-theory picture, the statistical majority of these base threefolds will give rise to exceptional gauge groups such as E8. I'll discuss its interesting physical implications on model building.


Speaker: Matthias Gaberdiel [ETH Zurich]


Speaker:Jie-qiang Wu [MIT]

Title: Quantum dynamics for Sine square deformed CFT (One example for 1+1d CFT on curved space)