Masters Theses

Keywords and Phrases

Cobalt Niobate; Disorder; Infinite Randomness; Ising Model; Quantum Phase Transitions

Abstract

We explore the phase transition in the diluted quasi-one-dimensional quantum Ising model. We begin by giving an introduction to the Ising model followed by derivations of the properties and observables. A brief overview of Monte-Carlo simulations is also given focusing on two algorithms that make simulations for physically realizable systems possible, the Metropolis and Wolff algorithms. We finally discuss the concept of random disorder in the system and the effects this can have on the bulk of the system.

These concepts are then directly applied to a quasi-one-dimensional Ising model. Motivated by recent experiments on the spin-chain material cobalt niobate, we construct a quasi-one-dimensional quantum Ising model with anisotropic spatial interactions. We first consider the classical case. Using Monte Carlo simulations, we study its properties under site dilution.

We then consider the quantum phase transition which is driven by a transverse magnetic field. To do so, we map the transverse-field quantum Ising model to a 4D classical model, which we again study via Monte Carlo simulations.

Advisor(s)

Vojta, Thomas

Committee Member(s)

Kim, Hyunsoo
Medvedeva, Julia E.

Department(s)

Physics

Degree Name

M.S. in Physics

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2025

Journal article titles appearing in thesis/dissertation

Paper I: Pages 25-46 are intended for submission to Phys. Rev. B. The manuscript is available here.

Pagination

xi, 51 pages

Note about bibliography

Includes_bibliographical_references_(pages 45-46)

Rights

© 2025 Logan Bradley Sowadski , All Rights Reserved

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 12548

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