Anthony Pullen - Intensity Mapping to Probe the Interstellar Medium (September 27, 2019)

I will review how massive black holes may have formed in the earlyuniverse from stellar-mass black hole remnants, via super-Eddingtonaccretion, or run-away mergers of stellar-mass objects. I will thendiscuss the role of circumbinary gas in mergers of black holes: forfacilitating (or not) the early inspiral, producing uniqueelectromagnetic signatures, and impacting low-frequency gravitationalwaves.More details: https://www.simonsfoundation.org/event/cca-colloquium-zoltan-haiman/Uploaded 23-10-19 Learn more about your ad choices. Visit megaphone.fm/adchoices

Moduli Spaces of GraphsFinite metric graphs represent processes and objects in many different areas of mathematics and science, so one would like to understand the set of all graphs relevant to a given problem, i.e. the moduli space of such graphs. In this talk I will highlight some recent progress in the study of moduli spaces of graphs, first reviewing historical developments that have led up to them. I will concentrate on moduli spaces of graphs with a specified fundamental group, and explain how the study of such spaces both contributes to and profits from the theory of outer automorphism groups of free groups. Finally, I will mention connections with the classical symmetric space of lattices in Euclidean space, with Kontsevich’s graph complexes and with the algebraic geometers’ moduli space of tropical curves.Uploaded 09-09-26The ICM Emmy Noether Lecture honors women who have made fundamental and sustained contributions to the mathematical sciences. The ICM Emmy Noether Lecture is named after the German mathematician Emmy Noether. Since 2006, this lecture is a permanent ICM tradition, since 2014, a special commemorative plaquette is given to each ICM Emmy Noether Lecturer. Learn more about your ad choices. Visit megaphone.fm/adchoices

Leslie Schoop: Chemical bonds in square nets and their relation to topologyMore details: https://www.simonsfoundation.org/event/young-research-leaders-in-topological-materials-and-beyond/Uploaded 14-10-19 Learn more about your ad choices. Visit megaphone.fm/adchoices

The Lens of Abelian EmbeddingsWe discuss a recent line of research investigating inverse theorems with respect to general k-wise correlations, and explain how such correlations arise in different contexts in mathematics. We outline some of the results that were established and their applications in discrete mathematics and theoretical computer science.Uploaded 06-10-26 Learn more about your ad choices. Visit megaphone.fm/adchoices

Control of Some Coupled Pde Systems of Mixed TypesThe initial part of the talk reviews some results on control and stabilization of some coupled PDE systems of mixed types, obtained with our collaborators. The latter part is specifically on new results with our collaborators, on stabilization or the lack of, for these systems. An outline of the proof for both positive and negative results will be indicated. These do not use the full knowledge of the spectrum. The negative result relies on a construction of highly localized solutions using certain ansatz involving complex exponentials and hence works for such coupled systems with variable coefficients and lower order terms.Uploaded 07-10-26 Learn more about your ad choices. Visit megaphone.fm/adchoices

Line intensity mapping (LIM), in which line emission from unresolved galaxies is mapped onto a 3D field, has emerged as a unique probe of the gas content and star formation history of the Universe as well as large-scale structure across cosmic time. In this talk, I will present the science potential of LIM as well as surveys which will provide the data for these analyses. After a brief introduction to LIM, I will introduce the [CII] emission line and explain what mapping this line can teach us about star formation and the interstellar medium, after which I’ll present recent measurements we performed of the diffuse [CII] intensity. Next, I will describe the LIM survey EXCLAIM, a NASA mission which will map CO and [CII] emission to probe star formation and the ISM over cosmic time. Finally, I will present SPHEREx, another upcoming NASA mission which will characterize cosmic inflation as well as the ISM.More details: https://www.simonsfoundation.org/event/cca-colloquium-anthony-pullen/Uploaded 23-10-19 Learn more about your ad choices. Visit megaphone.fm/adchoices

Maia Garcia Vergniory: Topological semimetals, from theoretical prediction to experimental realizationMore details: https://www.simonsfoundation.org/event/young-research-leaders-in-topological-materials-and-beyond/Uploaded 14-10-19 Learn more about your ad choices. Visit megaphone.fm/adchoices

A Calabi-Yau Theorem for Degenerations of Compact Kähler ManifoldsTo understand a compact Kähler manifold X, it is often helpful to study its degenerations. The idea of non-Archimedean (n-A) Kähler geometry is to think of such degenerations as (possibly weak) Kähler potentials on an associated n-A space. The n-A Monge-Ampère measure of a degeneration is then supposed to encode how the volume of X distributes as X degenerates. In this talk I will discuss a Calabi-Yau theorem in this setting, first proved in the algebraic case by Sébastien Boucksom and Mattias Jonsson (building on earlier work of Sébastien Boucksom, Charles Favre and Mattias Jonsson), and subsequently proved in the general Kähler case by Pietro Mesquita-Piccione and myself. The proof in the Kähler case relies on properties of big cohomology classes, and is related to the transcendental Morse inequality conjecture of Sébastien Boucksom, Jean-Pierre Demailly, Mihai Păun and Thomas Peternell.Uploaded 06-10-26 Learn more about your ad choices. Visit megaphone.fm/adchoices

Geometric Characteristics of Observable RegionsObservability is one of the main research areas in control theory. Different forms of observability inequalities not only correspond to different control phenomena but also have their own mathematical meanings. For evolutionary partial differential equations (PDEs), looking into the geometric characteristics of their observable sets/regions is one of the key parts in studying the corresponding observability inequalities. However, research in this area is still far from well understood. In this paper, we first present four distinct observability inequalities within the framework of abstract evolution equations, together with their corresponding control problems. Then, for several specific evolution equations (such as wave equations, heat equations, Schrödinger equations, among others), we provide the definitions of observable sets/regions corresponding to the aforementioned inequalities. Subsequently, we review some existing results and main research methods concerning the geometric characteristics of these observable sets/regions. Finally, we outline several open problems related to the geometric characteristics of observable (and weakly observable, etc.) sets/regions.Uploaded 07-10-26 Learn more about your ad choices. Visit megaphone.fm/adchoices

More details: https://www.simonsfoundation.org/event/nyc-computational-cryo-em-summer-workshop/Uploaded 26-08-19 Learn more about your ad choices. Visit megaphone.fm/adchoices