## Files in this item

FilesDescriptionFormat

application/pdf

NAWAZ-DISSERTATION-2017.pdf (1MB)
(no description provided)PDF

## Description

 Title: Applications of Stein's method and large deviations principle's in mean-field O(N) models Author(s): Nawaz, Tayyab Director of Research: Kirkpatrick, Kay Doctoral Committee Chair(s): DeVille, Lee Doctoral Committee Member(s): Rapti, Zoi; Hirani, Anil Department / Program: Mathematics Discipline: Mathematics Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Mean-field Rate function Total spin Limit theorem Phase transition Abstract: In the first part of this thesis, we will discuss the classical XY model on complete graph in the mean-field (infinite-vertex) limit. Using theory of large deviations and Stein's method, in particular, Cramér and Sanov-type results, we present a number of results coming from the limit theorems with rates of convergence, and phase transition behavior for classical XY model. In the second part, we will generalize our results to mean-field classical $N$-vector models, for integers $N \ge 2$. We will use the theory of large deviations and Stein's method to study the total spin and its typical behavior, specifically obtaining non-normal limit theorems at the critical temperatures and central limit theorems away from criticality. Some of the important special cases of these models are the XY ($N=2$) model of superconductors, the Heisenberg ($N=3$) model (previously studied in [KM13] but with a correction to the critical distribution here), and the Toy ($N=4$) model of the Higgs sector in particle physics. Issue Date: 2017-04-07 Type: Thesis URI: http://hdl.handle.net/2142/97544 Rights Information: Copyright 2017 Tayyab Nawaz Date Available in IDEALS: 2017-08-10 Date Deposited: 2017-05
﻿