{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/319139"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/319139","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Communal pairing in Fermi gases with attractive interactions","abstract":"Weak attractive interactions in a spin-balanced fermion gas are known to induce a Cooper pairing instability where the fermion pairs have zero net momentum, leading to BCS superconductivity. Extensions for spin-imbalanced systems include breached superfluids, Fulde–Ferrell–Larkin–Ovchinnikov theory, and pair density wave theory. We propose a further extension of a superconducting state, dubbed a communal pairing state, whose underlying components are superpositions of Cooper pairs that share minority-spin fermions. This state includes correlations between all available fermions on both Fermi surfaces and is shown to be energetically favourable to the Fulde-Ferrell-Larkin-Ovchinnikov state. Our numerical quantum Monte Carlo study of finite spin-imbalanced systems provides clear evidence of the existence of such exotic pairing states. In spin-balanced systems, temporal fluctuations of the order parameter promote communal pairing, leading to a widening in momentum space of the superconducting gap and a decrease of the chemical potential.","abstract_html":"Weak attractive interactions in a spin-balanced fermion gas are known to induce a Cooper pairing instability where the fermion pairs have zero net momentum, leading to BCS superconductivity. Extensions for spin-imbalanced systems include breached superfluids, Fulde–Ferrell–Larkin–Ovchinnikov theory, and pair density wave theory. We propose a further extension of a superconducting state, dubbed a communal pairing state, whose underlying components are superpositions of Cooper pairs that share minority-spin fermions. This state includes correlations between all available fermions on both Fermi surfaces and is shown to be energetically favourable to the Fulde-Ferrell-Larkin-Ovchinnikov state. Our numerical quantum Monte Carlo study of finite spin-imbalanced systems provides clear evidence of the existence of such exotic pairing states. In spin-balanced systems, temporal fluctuations of the order parameter promote communal pairing, leading to a widening in momentum space of the superconducting gap and a decrease of the chemical potential.","abstract_has_math":false,"creators":["Foo, Darryl"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Conduit, Gareth"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08-01","date_published":"2020-08-01","updated_at":"2026-07-22T22:24:10Z","subjects":["Superconductors","Fermi gases","Computational physics"],"languages":["eng"],"rights":[],"rights_urls":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/35a6a96e-4563-41cb-b1db-267c3c851657/download","https://creativecommons.org/licenses/by/4.0/"],"identifier_entries":[{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000175651383","0000000338076361"],"render_values":[{"text":"0000-0001-7565-1383","href":"https://orcid.org/0000-0001-7565-1383","code":true},{"text":"0000-0003-3807-6361","href":"https://orcid.org/0000-0003-3807-6361","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.66258","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Conduit, Gareth"]},{"key":"dc:creator","label":"Author","values":["Foo, Darryl"]},{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000175651383","0000000338076361"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2020-08-01"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/319139"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Superconductors","Fermi gases","Computational physics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/35a6a96e-4563-41cb-b1db-267c3c851657/download","https://creativecommons.org/licenses/by/4.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.17863/CAM.66258"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/86554453-a8cd-4eb7-b2e1-198c166cfe29/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Weak attractive interactions in a spin-balanced fermion gas are known to induce a Cooper pairing instability where the fermion pairs have zero net momentum, leading to BCS superconductivity. 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In spin-balanced systems, temporal fluctuations of the order parameter promote communal pairing, leading to a widening in momentum space of the superconducting gap and a decrease of the chemical potential."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["e51838782431a263a89773b1eae7dcc5","353adac0d1ebdfd65ab16480263c3c87"]},{"key":"dc:title","label":"Title","values":["Communal pairing in Fermi gases with attractive interactions"]}]}],"canonical_facts":{"dc:contributor.advisor":["Conduit, Gareth"],"dc:creator":["Foo, Darryl"],"dc:creator.authoridentifier":["0000000175651383","0000000338076361"],"dc:date.issued":["2020-08-01"],"dc:description.abstract":["Weak attractive interactions in a spin-balanced fermion gas are known to induce a Cooper pairing instability where the fermion pairs have zero net momentum, leading to BCS superconductivity. Extensions for spin-imbalanced systems include breached superfluids, Fulde–Ferrell–Larkin–Ovchinnikov theory, and pair density wave theory. We propose a further extension of a superconducting state, dubbed a communal pairing state, whose underlying components are superpositions of Cooper pairs that share minority-spin fermions. This state includes correlations between all available fermions on both Fermi surfaces and is shown to be energetically favourable to the Fulde-Ferrell-Larkin-Ovchinnikov state. Our numerical quantum Monte Carlo study of finite spin-imbalanced systems provides clear evidence of the existence of such exotic pairing states. 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