Upcoming Talk:
Title: Investigations on the Non-Hermitian Skin Effect
Speaker: Zixi Fang
Date: Thursday 23 November 2023
Time: 19:20-21:45 (Beijing time)
Venue: Shuangqing Complex B627
Abstract:
The non-Hermitian system has been extensively researched in recent years. The concept of the non-Hermitian skin effect is intriguing as it violates the Bloch theorem, causing the eigenstates of the system to differ significantly under open boundary conditions compared to periodic boundary conditions. In this presentation, I will introduce the concept of the non-Hermitian skin effect, highlighting its distinctive features such as scattering invisibility, unstable bound states, and more.
Past Talks：
Title: Dubrovin conjecture from a GLSM viewpoint
Speaker: Jin Chen
Date: Tuesday 7 November 2023
Time: 19:20-21:45 (Beijing time)
Venue: https://meeting.tencent.com/dm/gJlEuNxsyRqt
Abstract:
Dubrovin conjecture establishes a relation between the Stokes data for the quantum cohomology of a Fano variety X, and the exceptional collection of the objects in the derived category of coherent sheaves on X. In this talk, I will explain how to interpolate the two objects via the hemi-sphere partition function of a GLSM with the target space of X. In this setup, the Stokes data can be interpreted as soliton numbers between different vacua in the deep infra-red, while the exceptional collection is identified as B-branes in the weakly coupled geometric phase of the theory. In addition, by introducing twisted masses, I will also show how to generalize the Dubrovin conjecture in an equivariant way.
Title: 2d-4d correspondence from the Nekrasov partition function
Speaker: Yihua Liu
Date: Tuesday 31 October 2023
Time: 19:20-21:45 (Beijing time)
Venue: Shuangqing Complex A513
Abstract:
In this talk I will briefly introduce the 2d-4d correspondence in terms of the Nekrasov partition function with irregular Liouville conformal blocks, and the construction of irregular correlation function from free field realizations, and another integrable system that the irregular conformal blocks satisfies.
Title: Disk partition function of 2d N=(2,2) GLSM
Speaker: Bo Lin
Date: Tuesday 24 October 2023
Time: 19:20-21:45 (Beijing time)
Venue: Shuangqing Complex A513
Abstract:
In this talk I’ll introduce the disk partition function of 2d N=(2,2) GLSM with boundary, together with several properties of quantum Kahler moduli space and its resolution which shall be close related to the symmetry of derived category.
Title: 2d Free Fermion Carrollian CFT Model
Speaker: Zehua Xiao
Date: Tuesday 17 October 2023
Time: 19:20-21:45 (Beijing time)
Venue: Shuangqing Complex A513
Abstract:
I will introduce the 2d free fermion model on the Galilean/Carrollian geometry. In this model, the modes of the Noether charges form an infinite dimensional BMS algebra. After canonical quantization, we find the fusion laws of the primary operators in NS vacuum and R vacuum in highest weight representation. All states in highest weight representation are generated by four primaries and one seed operator K. The organization of these states forms a staggered module. We also calculate the correlation functions and partition functions for the highest weight representation and the induced representation. Together with the 2d free BMS scalar model, we construct an N=2 supersymmetric Carrollian CFT model and the supercharges indeed lead to the BMS SUSY algebra.
Title: Holography and Koszul duality
Speaker: Tianqing Zhu
Date: Tuesday 10 October 2023
Time: 19:20-21:45 (Beijing time)
Venue: Shuangqing Complex A513
Abstract:
I will illustrate the idea that the holography in the twisted case can be interpreted as Koszul duality in mathematics. As examples, I will show the example of the holography between N D2 branes and K D4 branes in a 6d topological string theory, which can be interpreted as the duality between the large N instanton moduli space and the gl_K spin chain.
Ref: 1809.00372, 2111.06876, 1505.06703, 1606.00365, 1705.02500, 1709,09993, 2001.02177
