Week of February 14, 2021

Wed Feb 17, 2021
1:00pm to 2:00pm - Zoom: https://uci.zoom.us/j/91548266534 - Algebra
Robert Walker - (University of Wisconsin)
Uniform Asymptotic Growth of Symbolic Powers of Ideals

 

 

Algebraic geometry (AG) is a major generalization of linear algebra which is fairly influential in mathematics. Since the 1980's with the development of computer algebra systems like Mathematica, AG has been leveraged in areas of STEM as diverse as statistics, robotic kinematics, computer science/geometric modeling, and mirror symmetry. Part one of my talk will be a brief introduction to AG, to two notions of taking powers of ideals (regular vs symbolic) in Noetherian commutative rings, and to the ideal containment problem that I study in my thesis. Part two of my talk will focus on stating the main results of my thesis in a user-ready form, giving a "comical" example or two of how to use them. At the risk of sounding like Paul Rudd in Ant-Man, I hope this talk will be awesome.

Thu Feb 18, 2021
9:00am to 10:00am - Zoom - Inverse Problems
Carola-Bibiane Schönlieb - (University of Cambridge)
Machine Learned Regularization for Solving Inverse Problems

https://sites.uci.edu/inverse/

10:00am to 11:00am - zoom https://uci.zoom.us/j/93076750122?pwd=Y3pLdndoQTBuNUhxQUxFMkQ2QnRFQT09 - Mathematical Physics
Ilya Kachkovskiy - (MSU)
Something Cool
3:00pm to 4:00pm - Zoom: https://uci.zoom.us/j/95368666415 - Number Theory
Shamil Asgarli - (UBC)
On the proportion of transverse-free curves

 

 

Given a smooth plane curve C defined over an arbitrary field k, we say that C is transverse-free if it has no transverse lines defined over k. If k is an infinite field, then Bertini's theorem guarantees the existence of a transverse line defined over k, and so the transverse-free condition is interesting only in the case when k is a finite field F_q. After fixing a finite field F_q, we can ask the following question: For each degree d, what is the fraction of degree d transverse-free curves among all the degree d curves? In this talk, we will investigate an asymptotic answer to the question as d tends to infinity. This is joint work with Brian Freidin.

Fri Feb 19, 2021
4:00pm - Zoom - Graduate Seminar
Alexander Figotin - (UC Irvine)
TBA

TBA

4:00pm to 5:00pm - Zoom - Graduate Seminar
Alexander Figotin - (UCI)
A sketch of the neoclassical electromagnetic theory

Abstract

This presentation is about our recently developed neoclassical theory of electromagnetic interactions. We demonstrate that the classical EM theory can be extended down to atomic scales so that many phenomena at atomic scales, usually explained in the quantum-mechanical framework, can be explained in our neoclassical framework. The proposed extension bridges the classical and quantum-mechanical approaches, so they are not separated by a gap but rather overlap in a large common domain. Our theory, though similar to QM in some respects, is markedly different from it. In particular: (i) there is no need in our theory for the correspondence principle and consequent quantization procedure to obtain the wave equation; (ii) the Heisenberg uncertainty principle, though quite often applicable, is not a universal principle; (iii) there is no configuration space; (iv) there is no probabilistic interpretation of the wave function.

Our theory features a new spatial scale - the size a_{\mathrm{e}} of a free electron. This scale is special to our theory and does not appear in either classical EM theory nor in the quantum mechanics where electron is always a point-like object. Our current assessed value for this scale is a_{\mathrm{e}}\approx100a_{\mathrm{B}} where a_{\mathrm{B}} is the Bohr radius, and consequently a_{\mathrm{e}}\approx5 nm. In our theory any elementary charge is a distributed in space quantity. Its size is understood as the localization radius which can vary depending on the situation. For instance, if an electron is bound to a proton in the Hydrogen atom then its the size of is approximately 1 Bohr radius, that is a_{\mathrm{B}}\approx0.05 nm, and when the electron is free its size is a_{\mathrm{e}}\approx100a_{\mathrm{B}}\approx5 nm.

Interestingly, the upper bound 25 nm is the skin depth and that implies that a nanosystem of size smaller than 25 nm is transparent to the external field. The same transparency should hold for a nanostructured surface indicating such a surface is better for nearly ideal field electron emission. There is an experimental evidence showing that the highest current densities were obtained for nanotips with sizes about 1nm yet another important fact supporting a possibility of a fundamental nanoscale.