A sketch of the neoclassical electromagnetic theory

Speaker: 

Alexander Figotin

Institution: 

UCI

Time: 

Friday, February 19, 2021 - 4:00pm to 5:00pm

Host: 

Location: 

Zoom

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.

Codes from Polynomials over Finite Fields

Speaker: 

Nathan Kaplan

Institution: 

UC Irvine

Time: 

Friday, May 28, 2021 - 4:00pm

Host: 

Location: 

Zoom https://zoom.us/j/8473088589

 

Suppose we are trying to communicate over a 'noisy channel'. I want to send you a single bit, a 1 or a 0, but there is some probability that the bit I send is not the bit you receive. We could communicate more reliably by agreeing to repeat the intended message, for example, instead of sending '0’ or '1’, I would send '000’ or '111’. But, there is a cost to this repetition. A major goal in the theory of error-correcting codes is to understand how to efficiently build redundancy into messages so that we can identify and correct errors. In this talk we will focus on error-correcting codes that come from families of polynomials over finite fields, starting from the classical example of Reed-Solomon codes. We will emphasize connections between coding theory, algebraic geometry, and number theory. This talk will assume no previous familiarity with coding theory or algebraic geometry. We will start with the basics and emphasize concrete examples.

Relative consistencies: How large sets sometimes influence the behavior of small sets.

Speaker: 

Martin Zeman

Institution: 

UC Irvine

Time: 

Friday, February 5, 2021 - 4:00pm

Host: 

Location: 

Zoom Id: 946 8552 8096

In set theory one encounters statements which cannot be decided within a background theory one works in. Some of these statemetns can be shown to be consistent within standard background theories widely accepted in mathematics, but some of them require the use of very large sets, known under the term ``large cardinals". In this talk I will discuss how large cardinas naturally arise when studying relative consistencies and also give examples from mainstream mathematics which lead to relative consistencies and large cardinals.

Adventures in noncommutative algebra

Speaker: 

Manuel Reyes

Institution: 

UC Irvine

Time: 

Friday, January 29, 2021 - 4:00pm to 5:00pm

Host: 

Location: 

Zoom (link in abstract)

This presentation will begin with an introduction to noncommutative rings by way of several examples. I will then discuss two research programs that share the common motivation of producing methods to view noncommutative pehnomena as an extension of commutative algebra, as follows:

  1. The search for a functor that extends the Zariski spectrum from commutative to noncommutative rings.
  2. Finding ways to infer good ring-theoretic properties from good homological properties.

Zoom link: https://uci.zoom.us/j/95978949132?pwd=QzliZ0RWc2RyWURtSi9XS0FwRmZSZz09

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