| Monday 6 May 2024 | |
| Events for day: Wednesday 02 March 2022 |
| 11:00 - 12:00 Wednesday Weekly Seminar - google meet Search for invisible decay of the Higgs boson with the CMS detector School PARTICLES AND ACCELERATORS Since its discovery in 2012, the Higgs boson properties have been studied in details by the ATLAS and CMS collaborations. Of particular interest is its decay branching ratio to invisible particles, expected to be very small by the Standard Model, but that could be significantly enhanced in case of couplings to new particles such as particles of dark matter. In this seminar, I will present the latest results from the CMS collaboration related to the search for such decays of the Higgs boson when it is produced through the fusion of vector bosons, from far the most sensitive channel experimentally. The various steps of the analysis will ... 13:30 - 15:00 Weekly Seminar (Online) Cosmological constant problem on the horizon https://www.skyroom.online/ch/soa/weekly-seminar School ASTRONOMY We revisit the quantum cosmological constant problem and highlight the important roles played by the dS horizon of zero point energy. We argue that fields which are light enough to have dS horizon of zero point energy comparable to the FLRW Hubble radius are the main contributor to dark energy. On the other hand, the zero point energy of heavy fields develop nonlinearities on sub-Hubble scales and can not contribute to dark energy. Our proposal provides a simple resolution for both the old and new cosmological constant problems by noting that there exists a field, the (lightest) neutrino, which happens to have a mass comparable to the present ... 14:00 - 15:00 Combinatorics and Computing Weekly Seminar Distributed Sparse Feature Selection in Communication-Restricted Networks School MATHEMATICS In this talk, I will introduce and theoretically analyze a new distributed scheme for sparse linear regression and feature selection in high dimensions. The primary goal is to learn the few causal features of a high-dimensional dataset based on noisy observations from an unknown sparse linear model. However, the presumed training set is already distributed over a large star-shaped network whose client nodes are connected to a central server node through extremely low-bandwidth links. In this regard, a simple yet effective method will be proposed which is theoretically guaranteed to recover the causal dimensions at the cost of a negligible ban ... 14:00 - 15:00 Weekly Seminar Condensed Matter and Statistical Physics Group RGreen-X library: Exascale Green-Function-Based Methods School PHYSICS Abstract: A new open-source exascale library of Green-function-based methodologies is under developing. Its layered design will separate higher-level functionalities from architecture-dependent numerical routines, common to all code families. Considerations of scaling with system size favour the choice of algorithms based on real space sparseness and time-frequency transforms, like the real-space / imaginary-time approach (cubic scaling instead of the quartic scaling of other algorithms), whose larger amount of numerical evaluations as compared to data communication is also well suited for the massive parallelism in exascale machines. ... 16:00 - 17:00 Mathematics Colloquium On the Riemann Zeta Function School MATHEMATICS I will discuss the Riemann zeta function and the significance of its zeros to prime numbers. Also, I will look at the distribution of zeta zeros and mention some of my related works on the subject. To get more information about the colloquium, join to the following google group: https://groups.google.com/g/ipm-math-colloquium ... 18:00 - 19:00 Physics Colloquium Dance of Cause and Effect: Fluctuation Induced Reduction of Dissipation in Classical Fluids School PHYSICS About seventy years ago, G I Taylor noticed that the tails of two closely swimming spermatozoa, oscillate in a synchronized fashion as if both of them are controlled from one regulating center. The two sperms, on the other hand, has no mean of communication, but the viscous fluid in which they are swimming. To address the why question, behind the observation, he suggested the minimization of total dissipation in the viscous medium. Sixty years later, Taylors original idea was put to more detailed analytical investigations; non-intuitively, it failed to attribute the observed synchronization to the expected reduction of dissipation. We begin w ... |