Revisiting physics of quantum bits

Advancements in the technology of quantum bits invoke more precise calculations for decoherence and dissipative effects. In this thesis, the physics of truncated two level systems is revisited and it is shown that in some systems, such as in triple-junction superconducting flux qubit, environmental noises that are usually recognized to only have dissipative effects and the trivial resultant dephasing, can also cause pure dephasing. Furthermore, it is demonstrated that, in the current domain of interest for quantum computation purposes, the effective Hamiltonian of single molecule magnets in interaction with a spin bath differs from the commonly quoted result in the literature. It is also shown that the topological effects in such problems are as small as transitional effects to higher excited states beyond the two-level picture. Finally, a simulation of the quantum noise by the classical noise and a simulation of spin bath by oscillator bath for a quantum bit as the principal system are presented.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Halataei, Seyyed Mohammad Hassan

Contributors dc:contributor

• Leggett, Anthony J.
• Cooper, Lance
• Weissman, Michael B.
• Bezryadin, Alexey

• Qubit
• Decoherence
• Dissipation
• Superconducting Qubit
• Flux Qubit
• Nano magnetic molecule
• Molecular qubit
• Quantum noise simulation
• oscillator bath simulation
• spin bath
• mapping
• Double well potential
• Classical noise
• Landau-Zener effect

Statement dc:rights

• Copyright 2017 by Seyyed Mohammad Hassan Halataei. All rights reserved.

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/99318

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/99318