| Sunday 22 December 2024 | |
| Events for day: Wednesday 28 February 2024 |
| 13:30 - 15:00 Weekly Seminar Cosmological Phonon Collider School ASTRONOMY The expansion of the universe spontaneously breaks time translation by selecting a preferred time foliation. As a consequence, very much like a superfluid at zero temperature, the low-energy description of single-field inflation can be organised in terms of the associated Goldstone mode of the broken symmetry (aka the phonon). Similar to particle colliders, if we were to scatter sound waves, the presence of additional heavy fields coupled to the medium would manifest as distinct peaks in the cross-section of the phonons. In this talk, I introduce a cosmological version of this idea, in which the imprints of additional heavy particles during i ... 14:00 - 15:00 Combinatorics and Computing Weekly Seminar Binary Stretch Embedding of Weighted Graphs School MATHEMATICS In this talk, we explore a new problem of graph metric embeddings, namely the binary stretch embedding problem (BSEP), for edge-weighted graphs. BSEP is a variant of the classical addressing problem of Graham and Pollak, which asks for the minimum length vectors/addresses that preserve the distances between the vertices of a graph. We show that BSEP is equivalent to finding a graph embedding into the Hamming space with minimum binary stretch, which is the ratio of the Hamming distance to the edge weight. We relate BSEP to other graph embedding problems in the literature and present some results on the binary stretch of various classe ... 14:00 - 15:00 Wednesday Weekly Seminar - meeting The role of elementary particle physics in astrophysics School PARTICLES AND ACCELERATORS Abstract: Investigating the structural properties of the compact stars is not possible without knowing the equation of state. The equation of state is obtained from the degrees of freedom of the system and the interaction between its particles. Therefore, the equation of state depends on the models of elementary particle physics and nuclear physics. In this talk, it is explained that what the equation of state is and how it is related to astrophysics. Indico Link https://indico.hep.ipm.ir/e/j.sedaghat Link to join the webinar: https://meet.google.com/fnv-dfkk-ghb ... 15:15 - 16:30 Geometry and Topology Weekly Seminar Spectral Simplicity and Asymptotic Separation of Variables School MATHEMATICS Asymptotic separation of variables is a tool that Chris Judge and I introduced to prove the generic simplicity of Euclidean triangles. I will explain the ideas behind this approach and how it can be applied to different simple shapes. Location: https://meet.google.com/you-qymk-ybu Venue: , (Online) ... 16:30 - 17:30 Lecture Invariants, Moduli Spaces and the Character Varieties School MATHEMATICS Many of the most important problems in mathematics concern classification. In algebraic and in geometric classifications these problems were greatly unified by the notion of moduli space, introduced by Riemann and developed by Mumford. In this talk we will briefly introduce the moduli spaces of representations of finitely presented groups into a complex reductive Lie group, which are so called character varieties. These spaces have been studied intensively during the last few decades, in part, due to their deep connections to multiple research streams. We then will survey recent results in the computations of their polynomial invariants ... 18:00 - 19:30 Physics Colloquium Theoretical and Computational Aspects of Neuroscience School PHYSICS Date and time, 6-7:30pm, Wednesday 9 Esfand 1402 (28 Feb. 2024). Venue: Online Link https://www.skyroom.online/ch/schoolofphysics/colloquium ... 18:15 - 19:30 Algebraic Geometry Biweekly Webinar Cohomology and Motives of Moduli Spaces of Higgs Bundles and Motivic Mirror Symmetry School MATHEMATICS Higgs bundles are vector bundles equipped with an additional "twisted endomorphism". Introduced by Nigel Hitchin in a context of mathematical physics, they have turned to be central objects in differential and algebraic geometry. In particular, moduli spaces of Higgs bundles have a very rich geometry that is both related to the geometry of moduli of vector bundles but also has additional symplectic features. I will introduce these moduli spaces and discuss some of what is known about their cohomology and their motivic invariants. There has been a lot of recent progress in this direction and I will try to describe the main threads. I will con ... |