{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20190"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20190","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Bose-Einstein condensation of excitons in uniaxially stressed cuprous oxide","abstract":"Excitons in Cu$\\sb2$O have been demonstrated to be a nearly ideal gas of bosons, providing a unique system for studying Bose-Einstein statistics and Bose-Einstein Condensation of an ideal gas in the laboratory. In this study, I have applied uniaxial stress to optimize the conditions for a Bose-Einstein Condensation phase transition of the excitons in this crystal. Using time-resolved photoluminescence, an enhanced quantum degeneracy of the orthoexcitons is observed in this stressed crystal due to the lowered multiplicity of the orthoexciton ground state, although no evidence of the condensation phase of the orthoexcitons is observed. In contrast, I have found compelling evidence for Bose-Einstein Condensation of the singlet paraexcitons in uniaxially stressed Cu$\\sp2$O. When the paraexciton gas attains a particle density exceeding the critical density for Bose-Einstein condensation, the paraexciton spectrum develops an extra component at low energy which is about 0.1-0.3 meV above the zero-kinetic-energy state. I also observe an anomalous spatial transport of the paraexcitons when this low-energy component is present. This ballistic wave-like (or drift-like) motion occurs at an expansion rate 3 $\\times$ 10$\\sp5$ cm/sec to 4 $\\times$ 10$\\sp5$ cm/sec, roughly correlated with a blue-shift of 0.1-0.3 meV for the low-energy component of the paraexcitons. I therefore interpret the low-energy component of the paraexcitons as a Bose-Einstein condensation peak.","abstract_html":"Excitons in Cu$\\sb2$O have been demonstrated to be a nearly ideal gas of bosons, providing a unique system for studying Bose-Einstein statistics and Bose-Einstein Condensation of an ideal gas in the laboratory. In this study, I have applied uniaxial stress to optimize the conditions for a Bose-Einstein Condensation phase transition of the excitons in this crystal. Using time-resolved photoluminescence, an enhanced quantum degeneracy of the orthoexcitons is observed in this stressed crystal due to the lowered multiplicity of the orthoexciton ground state, although no evidence of the condensation phase of the orthoexcitons is observed. In contrast, I have found compelling evidence for Bose-Einstein Condensation of the singlet paraexcitons in uniaxially stressed Cu$\\sp2$O. When the paraexciton gas attains a particle density exceeding the critical density for Bose-Einstein condensation, the paraexciton spectrum develops an extra component at low energy which is about 0.1-0.3 meV above the zero-kinetic-energy state. I also observe an anomalous spatial transport of the paraexcitons when this low-energy component is present. This ballistic wave-like (or drift-like) motion occurs at an expansion rate 3 $\\times$ 10$\\sp5$ cm/sec to 4 $\\times$ 10$\\sp5$ cm/sec, roughly correlated with a blue-shift of 0.1-0.3 meV for the low-energy component of the paraexcitons. I therefore interpret the low-energy component of the paraexcitons as a Bose-Einstein condensation peak.","abstract_has_math":true,"creators":["Lin, Jia Ling"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:31:42Z","date_published":"2011-05-07T12:31:42Z","updated_at":"2026-07-22T22:25:15Z","subjects":["Physics, Condensed Matter"],"languages":["eng"],"rights":["Copyright 1994 Lin, Jia Ling"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9522140","(UMI)AAI9522140"],"render_values":[{"text":"AAI9522140","href":null,"code":true},{"text":"(UMI)AAI9522140","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20190","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Lin, Jia Ling"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:31:42Z","10000-01-01","1994"]},{"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":["Physics, Condensed Matter"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1994 Lin, Jia Ling"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9522140","(UMI)AAI9522140","http://hdl.handle.net/2142/20190"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Excitons in Cu$\\sb2$O have been demonstrated to be a nearly ideal gas of bosons, providing a unique system for studying Bose-Einstein statistics and Bose-Einstein Condensation of an ideal gas in the laboratory. In this study, I have applied uniaxial stress to optimize the conditions for a Bose-Einstein Condensation phase transition of the excitons in this crystal. Using time-resolved photoluminescence, an enhanced quantum degeneracy of the orthoexcitons is observed in this stressed crystal due to the lowered multiplicity of the orthoexciton ground state, although no evidence of the condensation phase of the orthoexcitons is observed. In contrast, I have found compelling evidence for Bose-Einstein Condensation of the singlet paraexcitons in uniaxially stressed Cu$\\sp2$O. When the paraexciton gas attains a particle density exceeding the critical density for Bose-Einstein condensation, the paraexciton spectrum develops an extra component at low energy which is about 0.1-0.3 meV above the zero-kinetic-energy state. I also observe an anomalous spatial transport of the paraexcitons when this low-energy component is present. This ballistic wave-like (or drift-like) motion occurs at an expansion rate 3 $\\times$ 10$\\sp5$ cm/sec to 4 $\\times$ 10$\\sp5$ cm/sec, roughly correlated with a blue-shift of 0.1-0.3 meV for the low-energy component of the paraexcitons. I therefore interpret the low-energy component of the paraexcitons as a Bose-Einstein condensation peak.","Made available in DSpace on 2011-05-07T12:31:42Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9522140.pdf: 6592884 bytes, checksum: 01dfe8dc6e4971132fa8ce1653fcf5a5 (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:14Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:18:20-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Bose-Einstein condensation of excitons in uniaxially stressed cuprous oxide"]}]}],"canonical_facts":{"dc:creator":["Lin, Jia Ling"],"dc:date":["2011-05-07T12:31:42Z","10000-01-01","1994"],"dc:description":["Excitons in Cu$\\sb2$O have been demonstrated to be a nearly ideal gas of bosons, providing a unique system for studying Bose-Einstein statistics and Bose-Einstein Condensation of an ideal gas in the laboratory. In this study, I have applied uniaxial stress to optimize the conditions for a Bose-Einstein Condensation phase transition of the excitons in this crystal. Using time-resolved photoluminescence, an enhanced quantum degeneracy of the orthoexcitons is observed in this stressed crystal due to the lowered multiplicity of the orthoexciton ground state, although no evidence of the condensation phase of the orthoexcitons is observed. In contrast, I have found compelling evidence for Bose-Einstein Condensation of the singlet paraexcitons in uniaxially stressed Cu$\\sp2$O. When the paraexciton gas attains a particle density exceeding the critical density for Bose-Einstein condensation, the paraexciton spectrum develops an extra component at low energy which is about 0.1-0.3 meV above the zero-kinetic-energy state. I also observe an anomalous spatial transport of the paraexcitons when this low-energy component is present. This ballistic wave-like (or drift-like) motion occurs at an expansion rate 3 $\\times$ 10$\\sp5$ cm/sec to 4 $\\times$ 10$\\sp5$ cm/sec, roughly correlated with a blue-shift of 0.1-0.3 meV for the low-energy component of the paraexcitons. I therefore interpret the low-energy component of the paraexcitons as a Bose-Einstein condensation peak.","Made available in DSpace on 2011-05-07T12:31:42Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9522140.pdf: 6592884 bytes, checksum: 01dfe8dc6e4971132fa8ce1653fcf5a5 (MD5) Previous issue date: 1994","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:14Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:18:20-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9522140","(UMI)AAI9522140","http://hdl.handle.net/2142/20190"],"dc:language":["eng"],"dc:rights":["Copyright 1994 Lin, Jia Ling"],"dc:subject":["Physics, Condensed Matter"],"dc:title":["Bose-Einstein condensation of excitons in uniaxially stressed cuprous oxide"],"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":"2026-07-22T22:25:15Z"}