{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/32121"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/32121","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Low-frequency 1/f noise : low temperature measurements and effect on superconducting qubit dephasing","abstract":"Low-frequency noise caused by critical-current fluctuations in Josephson junctions can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure the noise power at 1 Hz down to 10 mK and verify a T2 dependence for T > 1 K, below which we observe a flattening of the noise magnitude versus temperature. In Al trilayer junctions we measure the critical-current noise power at 1 Hz from 10 mK to 1.4 K and find no dependence on temperature over this range. Possible reasons for the deviation from a T2 dependence are explored, including heating and sample quality. Simulations of the effect of 1/f noise are performed to examine the consequence of using different qubit sampling methods on expected dephasing times. Using the two sampling methods, we can probe the spectral nature and possible source of the dominant noise in a qubit.","abstract_html":"Low-frequency noise caused by critical-current fluctuations in Josephson junctions can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure the noise power at 1 Hz down to 10 mK and verify a T2 dependence for T > 1 K, below which we observe a flattening of the noise magnitude versus temperature. In Al trilayer junctions we measure the critical-current noise power at 1 Hz from 10 mK to 1.4 K and find no dependence on temperature over this range. Possible reasons for the deviation from a T2 dependence are explored, including heating and sample quality. Simulations of the effect of 1/f noise are performed to examine the consequence of using different qubit sampling methods on expected dephasing times. Using the two sampling methods, we can probe the spectral nature and possible source of the dominant noise in a qubit.","abstract_has_math":false,"creators":["Crane, Trevis Atherton"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-07-05T22:36:08Z","date_published":"2012-07-05T22:36:08Z","updated_at":"2026-07-22T22:25:30Z","subjects":["low-frequency noise","critical-current noise power","superconducting qubits"],"languages":["en"],"rights":["©2005 Crane"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["Q. 537.623 Tc5c","FILM 2005 C85"],"render_values":[{"text":"Q. 537.623 Tc5c","href":null,"code":true},{"text":"FILM 2005 C85","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/32121","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Crane, Trevis Atherton"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-07-05T22:36:08Z","10000-01-01","2005"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","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."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["low-frequency noise","critical-current noise power","superconducting qubits"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["©2005 Crane"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["Q. 537.623 Tc5c","FILM 2005 C85","http://hdl.handle.net/2142/32121"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Low-frequency noise caused by critical-current fluctuations in Josephson junctions can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure the noise power at 1 Hz down to 10 mK and verify a T2 dependence for T > 1 K, below which we observe a flattening of the noise magnitude versus temperature. In Al trilayer junctions we measure the critical-current noise power at 1 Hz from 10 mK to 1.4 K and find no dependence on temperature over this range. Possible reasons for the deviation from a T2 dependence are explored, including heating and sample quality. Simulations of the effect of 1/f noise are performed to examine the consequence of using different qubit sampling methods on expected dephasing times. Using the two sampling methods, we can probe the spectral nature and possible source of the dominant noise in a qubit.","Submitted by Rachelle Ramer (rramer2@illinois.edu) on 2012-07-05T22:36:08Z No. of bitstreams: 1 Crane.pdf: 4818221 bytes, checksum: 06990458919b428962e40875b7e56a69 (MD5)","Made available in DSpace on 2012-07-05T22:36:08Z (GMT). No. of bitstreams: 1 Crane.pdf: 4818221 bytes, checksum: 06990458919b428962e40875b7e56a69 (MD5) Previous issue date: 2005","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Rachelle Ramer (rramer2@illinois.edu) on 2012-07-05T22:36:08Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:33:28-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: thesis/dissertation","thesis/dissertation","U of I Only"]},{"key":"dc:title","label":"Title","values":["Low-frequency 1/f noise : low temperature measurements and effect on superconducting qubit dephasing"]}]}],"canonical_facts":{"dc:creator":["Crane, Trevis Atherton"],"dc:date":["2012-07-05T22:36:08Z","10000-01-01","2005"],"dc:description":["Low-frequency noise caused by critical-current fluctuations in Josephson junctions can lead to substantial, measurement-induced dephasing in superconducting qubits. The purpose of this work is to measure this noise as a function of temperature and to simulate its effect on the measurement dynamics associated with superconducting qubits. In Nb trilayer junctions we measure the noise power at 1 Hz down to 10 mK and verify a T2 dependence for T > 1 K, below which we observe a flattening of the noise magnitude versus temperature. In Al trilayer junctions we measure the critical-current noise power at 1 Hz from 10 mK to 1.4 K and find no dependence on temperature over this range. Possible reasons for the deviation from a T2 dependence are explored, including heating and sample quality. Simulations of the effect of 1/f noise are performed to examine the consequence of using different qubit sampling methods on expected dephasing times. Using the two sampling methods, we can probe the spectral nature and possible source of the dominant noise in a qubit.","Submitted by Rachelle Ramer (rramer2@illinois.edu) on 2012-07-05T22:36:08Z No. of bitstreams: 1 Crane.pdf: 4818221 bytes, checksum: 06990458919b428962e40875b7e56a69 (MD5)","Made available in DSpace on 2012-07-05T22:36:08Z (GMT). No. of bitstreams: 1 Crane.pdf: 4818221 bytes, checksum: 06990458919b428962e40875b7e56a69 (MD5) Previous issue date: 2005","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Rachelle Ramer (rramer2@illinois.edu) on 2012-07-05T22:36:08Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:33:28-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: thesis/dissertation","thesis/dissertation","U of I Only"],"dc:identifier":["Q. 537.623 Tc5c","FILM 2005 C85","http://hdl.handle.net/2142/32121"],"dc:language":["en"],"dc:rights":["©2005 Crane"],"dc:subject":["low-frequency noise","critical-current noise power","superconducting qubits"],"dc:title":["Low-frequency 1/f noise : low temperature measurements and effect on superconducting qubit dephasing"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:30Z"}