作者姓名：editor web

Speaker: Feng Hao (Shandong University) Abstract: One of Yau’s conjectures (ICCM 2013) says that canonically polarized complex projective manifolds do not admit nontrivial topological $S^1$-actions. In this talk, I will give a discussion on projective manifolds with topological $S^1$-actions, and show that canonically polarized complex projective manifolds do not admit free topological $S^1$-actions if their …

SIMIS Seminar on Algebraic Geometry: On Smooth Projective Manifolds with Topological Circle Bundle Structures 查看全文 »

Speaker: Dr. Gabriel Cardoso (Tsung-Dao Lee Institute, Shanghai Jiao Tong University) Abstract: Symmetry-protected topological (SPT) phases in insulators and superconductors are known for their robust edge modes, linked to topological invariants which are computed from the Berry connection defined in the bulk: the bulk-boundary correspondence. While this principle traditionally applies to gapped phases, recent advances …

SIMIS Seminar series on Quantum computing, Quantum simulation and Strongly-correlated systems: Gapless Floquet Topology 查看全文 »

Speaker: Jorge Olivares-Vinales (SCMS) Abstract: Lyapunov exponents play an important role in studying the ergodic behavior of dynamical systems. In particular, in the seminal work of Pesin, the existence and positivity of Lyapunov exponents were used to study the dynamics of non-uniformly hyperbolic systems. Since then, several extensions of this work have been developed for …

Lyapunov exponents, recurrence, and cusps 查看全文 »

Speaker: Aron Heleodoro (University of Hong Kong) Abstract: Let $F$ be a discretely valued local field with an algebraically closed residue field $k$, e.g.\ $F=\bC((t)), \overline{\bF}((t))$, or $W(\overline{\bF})$. Let $G$ be a connected reductive algebraic group over $F$. One can associate to $G$ the loop group $LG$ which is a (perfect) ind-scheme over $k$. I …

SIMIS Seminar on Derived and Noncommutative Geometry: Semi-orthogonal decomposition of conjugation equivariant sheaves on the loop group and affine character sheaves 查看全文 »

Speaker: Yingdi Qin (SIMIS) Abstract: In classical geometry, a symplectic structure on a manifold is a non-degenerate closed 2-form. And a submanifold Y is called Lagrangian if the pull back of the closed 2-form is trivial and the induced bundle map from TY to TY is an isomorphism. In derived geometry, tangent bundles are replaced …

SIMIS Seminar on Derived and Noncommutative Geometry: Introduction to Shifted Symplectic structure and Lagrangian structure 查看全文 »

Speaker: Jianpeng Liu Abstract: In this talk, we will discuss correlated and topological states emerging from heterostructure systems consisted of graphene and other insulating substrates. First, we consider moire superlattices formed by rhombohedral multilayer graphene aligned with hexagonal boron nitride (hBN) substrate [1], where we provide a microscopic theory for the integer and fractional Chern …

Simis Seminar series on Quantum computing, quantum simulation and strongly-correlated systems: Correlated and topological states in graphene-based heterostructures 查看全文 »

Speaker: Jiming Ma (Fudan University) Abstract: It is well known that the complex hyperbolic triangle group $\Delta(3,3,4)$ generated by three complex reflections $I_1,I_2,I_3$ in $\mathbf{PU}(2,1)$ has a 1-dimensional moduli space. Deforming the representations from the classical real Fuchsian one to $\Delta(3,3,4; \infty)$, that is, when $I_3I_2I_1I_2$ is accidental parabolic, the 3-manifolds at infinity change, from …

Geometry and topology seminar at Fudan & Simis: Figure-eight knot is always over there 查看全文 »

Speaker: Huichi Huang Host: Huaxin Lin Abstract: We give two equivalent conjectures of Furstenberg’s conjecture and these conjectures are in representation theory and Fourier analysis. Along the direction of Fourier analysis, we get some partial results. The talk is based on joint work with Jianchao Wu, Hanfeng Li, Enhui Shi and Hui Xu. Time: 2:30-3:30pm, …

An operator algebras seminar at SIMIS: Furstenberg’s conjecture and two related problems 查看全文 »

Speaker: Antony Speranza (University of Amsterdam) Abstract: Entanglement entropy in quantum field theory is UV-divergent, which makes it a challenging quantity to analyze from an algebraic perspective. In this talk, I will describe how perturbatively coupling to gravity improves this situation, resulting in a well-defined notion of renormalized entropy in the semiclassical limit. This entropy …

Physical Math Seminar @SIMIS: Entropy in gravitational von Neumann algebras 查看全文 »

Speaker: Qin Wang (East China Normal University) Host: Huaxin Lin Abstract: The uniform Roe algebra of a discrete metric space is a C*-algebra which analytically encodes the coarse geometry of the underlying space. It is known that counter-examples to the coarse Baum-Connes conjecture can be constructed by using expander graphs, the crucial point of which …

An operator algebras seminar at SIMIS: Expander graphs and ideal structure of uniform Roe algebras 查看全文 »