{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/99318"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/99318","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Revisiting physics of quantum bits","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Halataei, Seyyed Mohammad Hassan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Leggett, Anthony J.","Cooper, Lance","Weissman, Michael B.","Bezryadin, Alexey"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-03-13T15:45:12Z","date_published":"2018-03-13T15:45:12Z","updated_at":"2026-07-22T22:24:37Z","subjects":["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"],"languages":["en"],"rights":["Copyright 2017 by Seyyed Mohammad Hassan Halataei. All rights reserved."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/99318","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Leggett, Anthony J.","Cooper, Lance","Weissman, Michael B.","Bezryadin, Alexey"]},{"key":"dc:creator","label":"Author","values":["Halataei, Seyyed Mohammad Hassan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-03-13T15:45:12Z","2017-11-07","2017-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["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"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2017 by Seyyed Mohammad Hassan Halataei. 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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.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2018-03-13 without embargo terms","The student, Seyyed Mohammad Hassan Halataei, accepted the attached license on 2017-11-03 at 16:35.","The student, Seyyed Mohammad Hassan Halataei, submitted this Dissertation for approval on 2017-11-03 at 17:09.","This Dissertation was approved for publication on 2017-11-07 at 08:40.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11718 on 2018-03-13 at 10:08:18","Made available in DSpace on 2018-03-13T15:45:12Z (GMT). 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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.","Submission original under an indefinite embargo labeled 'Open Access'. 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All rights reserved."],"dc:subject":["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"],"dc:title":["Revisiting physics of quantum bits"],"dc:type":["text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:37Z"}