{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/95432"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/95432","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Delocalization phenomena in strongly disordered systems","abstract":"In this dissertation, we study delocalization mechanisms in strongly disordered systems. We focus on one-dimensional systems where the localizing effects of disorder are strongest. Our explorations of delocalization mechanisms will reveal new insights into the nature of Anderson transitions in the context of the entanglement, topology and interactions. We begin by proposing momentum entanglement as an efficient tool for detecting delocalized states in a broad class of disordered systems that undergo metal-insulator transitions. We find that the signatures of delocalized states in the momentum entanglement are remarkably clear. We explain this structure in the momentum entanglement by elucidating the underlying mechanism for delocalization in these disordered models. We will afterwards discuss a different type of delocalized state that arises at disorder-induced topological phase transitions. Anderson transitions in this case occur between insulating phases, with the emergence of critical states at the transition point. Through a mapping to a disordered spin chain, we provide a real-space description of the topology of the ground state and the delocalized state that emerges at the critical point. In this case, the mechanism that leads to delocalization reveals an unconventional type of disorder-induced topological phase transition that is fundamentally different, for example, from quantum Hall transitions. Finally, we examine delocalization processes in strongly interacting many-body localized phases. We find that strong interactions and the presence of symmetry constraints lead to an important spectral asymmetry in the localization transition. This asymmetry arises from the different dynamical properties of short-ranged correlated states that form due to having strong interactions. We explain how this asymmetry presents advantages in the numerical as well as experimental study of many-body localization transitions.","abstract_html":"In this dissertation, we study delocalization mechanisms in strongly disordered systems. We focus on one-dimensional systems where the localizing effects of disorder are strongest. Our explorations of delocalization mechanisms will reveal new insights into the nature of Anderson transitions in the context of the entanglement, topology and interactions. We begin by proposing momentum entanglement as an efficient tool for detecting delocalized states in a broad class of disordered systems that undergo metal-insulator transitions. We find that the signatures of delocalized states in the momentum entanglement are remarkably clear. We explain this structure in the momentum entanglement by elucidating the underlying mechanism for delocalization in these disordered models. We will afterwards discuss a different type of delocalized state that arises at disorder-induced topological phase transitions. Anderson transitions in this case occur between insulating phases, with the emergence of critical states at the transition point. Through a mapping to a disordered spin chain, we provide a real-space description of the topology of the ground state and the delocalized state that emerges at the critical point. In this case, the mechanism that leads to delocalization reveals an unconventional type of disorder-induced topological phase transition that is fundamentally different, for example, from quantum Hall transitions. Finally, we examine delocalization processes in strongly interacting many-body localized phases. We find that strong interactions and the presence of symmetry constraints lead to an important spectral asymmetry in the localization transition. This asymmetry arises from the different dynamical properties of short-ranged correlated states that form due to having strong interactions. We explain how this asymmetry presents advantages in the numerical as well as experimental study of many-body localization transitions.","abstract_has_math":false,"creators":["Mondragon Shem, Ian"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Hughes, Taylor L.","Ryu, Shinsei","Mason, Nadya","Dahmen, Karin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-03-01T15:51:13Z","date_published":"2017-03-01T15:51:13Z","updated_at":"2026-07-22T22:26:37Z","subjects":["Anderson localization","Disordered systems","Entanglement","Topological phases","Quantum phase transitions","Many-body localization"],"languages":["en"],"rights":["Copyright 2016 Ian Mondragon Shem"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/95432","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Hughes, Taylor L.","Ryu, Shinsei","Mason, Nadya","Dahmen, Karin"]},{"key":"dc:creator","label":"Author","values":["Mondragon Shem, Ian"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017-03-01T15:51:13Z","2016-08-01","2016-12"]},{"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":["Anderson localization","Disordered systems","Entanglement","Topological phases","Quantum phase transitions","Many-body localization"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2016 Ian Mondragon Shem"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/95432"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this dissertation, we study delocalization mechanisms in strongly disordered systems. We focus on one-dimensional systems where the localizing effects of disorder are strongest. Our explorations of delocalization mechanisms will reveal new insights into the nature of Anderson transitions in the context of the entanglement, topology and interactions. We begin by proposing momentum entanglement as an efficient tool for detecting delocalized states in a broad class of disordered systems that undergo metal-insulator transitions. We find that the signatures of delocalized states in the momentum entanglement are remarkably clear. We explain this structure in the momentum entanglement by elucidating the underlying mechanism for delocalization in these disordered models. We will afterwards discuss a different type of delocalized state that arises at disorder-induced topological phase transitions. Anderson transitions in this case occur between insulating phases, with the emergence of critical states at the transition point. Through a mapping to a disordered spin chain, we provide a real-space description of the topology of the ground state and the delocalized state that emerges at the critical point. In this case, the mechanism that leads to delocalization reveals an unconventional type of disorder-induced topological phase transition that is fundamentally different, for example, from quantum Hall transitions. Finally, we examine delocalization processes in strongly interacting many-body localized phases. We find that strong interactions and the presence of symmetry constraints lead to an important spectral asymmetry in the localization transition. This asymmetry arises from the different dynamical properties of short-ranged correlated states that form due to having strong interactions. We explain how this asymmetry presents advantages in the numerical as well as experimental study of many-body localization transitions.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo terms","The student, Ian Mondragon Shem, accepted the attached license on 2016-06-29 at 13:54.","The student, Ian Mondragon Shem, submitted this Dissertation for approval on 2016-06-29 at 14:28.","This Dissertation was approved for publication on 2016-08-01 at 09:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9721 on 2017-02-28 at 14:44:45","Made available in DSpace on 2017-03-01T15:51:13Z (GMT). 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We begin by proposing momentum entanglement as an efficient tool for detecting delocalized states in a broad class of disordered systems that undergo metal-insulator transitions. We find that the signatures of delocalized states in the momentum entanglement are remarkably clear. We explain this structure in the momentum entanglement by elucidating the underlying mechanism for delocalization in these disordered models. We will afterwards discuss a different type of delocalized state that arises at disorder-induced topological phase transitions. Anderson transitions in this case occur between insulating phases, with the emergence of critical states at the transition point. Through a mapping to a disordered spin chain, we provide a real-space description of the topology of the ground state and the delocalized state that emerges at the critical point. In this case, the mechanism that leads to delocalization reveals an unconventional type of disorder-induced topological phase transition that is fundamentally different, for example, from quantum Hall transitions. Finally, we examine delocalization processes in strongly interacting many-body localized phases. We find that strong interactions and the presence of symmetry constraints lead to an important spectral asymmetry in the localization transition. This asymmetry arises from the different dynamical properties of short-ranged correlated states that form due to having strong interactions. We explain how this asymmetry presents advantages in the numerical as well as experimental study of many-body localization transitions.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo terms","The student, Ian Mondragon Shem, accepted the attached license on 2016-06-29 at 13:54.","The student, Ian Mondragon Shem, submitted this Dissertation for approval on 2016-06-29 at 14:28.","This Dissertation was approved for publication on 2016-08-01 at 09:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9721 on 2017-02-28 at 14:44:45","Made available in DSpace on 2017-03-01T15:51:13Z (GMT). No. of bitstreams: 2 MONDRAGONSHEM-DISSERTATION-2016.pdf: 30044528 bytes, checksum: f1100f980ecc59afb7713819b578756f (MD5) LICENSE.txt: 4215 bytes, checksum: 52b8403fe10d6a8810265340ff16f44e (MD5) Previous issue date: 2016-08-01"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/95432"],"dc:language":["en"],"dc:rights":["Copyright 2016 Ian Mondragon Shem"],"dc:subject":["Anderson localization","Disordered systems","Entanglement","Topological phases","Quantum phase transitions","Many-body localization"],"dc:title":["Delocalization phenomena in strongly disordered systems"],"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":"2026-07-22T22:26:37Z"}