| Monday 22 July 2024 | |
| Events for day: Wednesday 29 May 2024 |
| 11:00 - 12:00 Wednesday Weekly Seminar - meeting Spectroscopy for asymmetric binary black hole mergers School PARTICLES AND ACCELERATORS Abstract: Spectroscopy and spectral analysis are widely used today for studying various objects using both optical and acoustic waves. All objects have natural frequencies based on their composition and structure, including black holes, which exhibit quasi-normal modes (QNMs) that can be detected through gravitational waves in binary black hole (BBH) mergers. Einstein's theory predicts how black holes vibrate and what QNM frequencies are allowed. Observing more than one ringdown mode (QNM) can test a fundamental prediction of Einstein's theory. I am a member of an international team engaged in black hole spectroscopy, and our m ... 13:30 - 15:00 Weekly Seminar The impact of massive neutrinos on the morphology of the Universe School ASTRONOMY The morphology of the cosmos provides valuable information about the structure of the cosmic web, which can be used for cosmological inferences. In this talk, I will discuss the capability of Persistent Homology (PH) as a morphological tool to investigate the impact of massive neutrinos on the Large-Scale Structure (LSS). PH naturally addresses the multi-scale topological characteristics of the LSS as a distribution of clusters, loops, and voids. Utilizing the Fisher forecast formalism, I will provide a quantitative assessment about the constraining power of some PH vectorizations to estimate the parameters of the $nu Lambda CDM$ model. ... 14:00 - 15:00 Combinatorics and Computing Weekly Seminar Hierarchical clustering via local search School MATHEMATICS In this talk I first give a short introduction to hierarchical clustering. Then I introduce Dasgupta's unsupervised objective function for hierarchical clustering (STOC 2016) and its dual version as studied by Moseley and Wang (NIPS 2017). Then I introduce a local search framework for hierarchical clustering and present some analysis of the locally optimal solutions within this framework based on Moseley and Wang revenue function. Furthermore a connection with the popular average linkage algorithm is established. If time allows, I show an implementation of the local search algorithm with some empirical results. Zoom room informat ... 17:30 - 19:00 Algebraic Geometry Biweekly Webinar Linear Combinations of Cohomological Invariants of Compact Complex Manifolds School MATHEMATICS In the 50s, Hirzebruch asked which linear combinations of Hodge and Chern numbers are topological invariants of compact complex manifolds. Building on ideas of Schreieder and Kotschick, who solved the K�hler case, I will present a general answer to this question (and some related ones). Furthermore, I will outline a program how to tackle similar questions when incorporating more cohomological invariants, eg the dimensions of the Bott Chern cohomology groups. This will naturally lead to an algebraic study of the structure of bicomplexes, as well as a number of challenging geometric construction problems. https://zoom.us/j ... |