Operator Theory and Applications

Washington University, Saint Louis MO

Investigators

Abstract

The Heisenberg uncertainty principle asserts that the order in which measurements are made matters; measuring the position of a particle before or after measuring its momentum affects the result. John von Neumann realized that the best way to capture this feature in a mathematical formulation was in terms of mathematical objects called operators. Studying operator theory is still fundamental not only in quantum mechanics, but in many areas of both pure and applied mathematics. Control theory, which is the design of things like automatic pilots and self-driving cars, depends critically on operator theory, and as these systems get more complex, new mathematical questions arise. The principal investigator will work on answering such questions. This project will study problems in operator theory, in function theory, and in the theory of noncommutative functions. Noncommutative functions are functions whose input consists of two (or more) matrices and whose output is a matrix. Roughly speaking they are generalized noncommutative polynomials in the same way that an analytic function is a generalized commutative polynomial. The theory of noncommutative functions is very new, but it has been successfully applied in diverse areas, including control theory, realization formulas, noncommutative algebraic geometry, and semi-definite programming. The principal investigator will use noncommutative function theory to study spectral theory, and operator monotonicity of functions, shedding light on the commutative theory also. In addition, he will work on using mathematical models to help understand the development of Alzheimer's disease.