{"id":{"repo_id":"toronto-retro","oai_identifier":"oai:utoronto.scholaris.ca:1807/97509"},"canonical_url":"https://search.dev.ndltd.org/etd/toronto-retro/oai:utoronto.scholaris.ca:1807/97509","repository":{"repo_id":"toronto-retro","name":"University of Toronto","base_url":"https://utoronto.scholaris.ca/server/oai/request"},"display":{"title":"Theory of Charge and Heat Transport Mechanisms in Nanodevices","abstract":"In this thesis, we pursue mechanisms in the nonequilibrium transport of charge and heat, to elucidate nanodevice operation, and explore fundamental theoretical questions. The thesis is divided into two parts. Part I explores in detail the role of incoherent effects on the charge transport behaviour of molecular junctions. Such effects, induced by molecular vibrations, solvent or other environmental effects, play a crucial role in many physical setups, but are difficult to simulate explicitly. We apply the Landauer-B\\\"uttiker probe technique, a phenomenological approach that incorporates incoherent effects at a low computational cost, and demonstrate the applicability of the technique by verifying that it captures a number of pertinent physical features, and achieves semi-quantitative agreement with experimental data. Going beyond this, we apply the probe method to a number of proposed physical setups. In stacked vs. alternating GC-rich ds-DNA, we find the even-odd effect in the experimentally observed conductance can be explained via a mixed coherent-incoherent transport mechanism. We find that in general, environmental interactions are destructive to the operation of molecular charge rectifiers, though in certain circumstances a weak rectifying behaviour might arise from many-body environmental effects. In Part II of this thesis we shift our focus to heat transport, and particularly the operation of quantum heat machines. We begin with a study of the role of so-called noise-induced coherences on the operation of a quantum absorption refrigerator. While in the past quantum coherences have usually been found to boost power in such setups, we observe a complete shutdown of the device when coherences survive to the nonequilibrium steady-state. We then extend our analysis, developing a general approach that one can use to more easily discover the role of coherences in quantum heat machines. We conclude with the development of a new numerically exact approach, the iterative full-counting statistics path integral (iFCSPI), which is suitable for simulations of heat transport in nanodevices. The iFCSPI allows the calculation of the cumulants of heat transport, as well as strong-coupling and non-Markovian effects, provided it can be converged.","abstract_html":"In this thesis, we pursue mechanisms in the nonequilibrium transport of charge and heat, to elucidate nanodevice operation, and explore fundamental theoretical questions. The thesis is divided into two parts. Part I explores in detail the role of incoherent effects on the charge transport behaviour of molecular junctions. Such effects, induced by molecular vibrations, solvent or other environmental effects, play a crucial role in many physical setups, but are difficult to simulate explicitly. We apply the Landauer-B\\"uttiker probe technique, a phenomenological approach that incorporates incoherent effects at a low computational cost, and demonstrate the applicability of the technique by verifying that it captures a number of pertinent physical features, and achieves semi-quantitative agreement with experimental data. Going beyond this, we apply the probe method to a number of proposed physical setups. In stacked vs. alternating GC-rich ds-DNA, we find the even-odd effect in the experimentally observed conductance can be explained via a mixed coherent-incoherent transport mechanism. We find that in general, environmental interactions are destructive to the operation of molecular charge rectifiers, though in certain circumstances a weak rectifying behaviour might arise from many-body environmental effects. In Part II of this thesis we shift our focus to heat transport, and particularly the operation of quantum heat machines. We begin with a study of the role of so-called noise-induced coherences on the operation of a quantum absorption refrigerator. While in the past quantum coherences have usually been found to boost power in such setups, we observe a complete shutdown of the device when coherences survive to the nonequilibrium steady-state. We then extend our analysis, developing a general approach that one can use to more easily discover the role of coherences in quantum heat machines. We conclude with the development of a new numerically exact approach, the iterative full-counting statistics path integral (iFCSPI), which is suitable for simulations of heat transport in nanodevices. The iFCSPI allows the calculation of the cumulants of heat transport, as well as strong-coupling and non-Markovian effects, provided it can be converged.","abstract_has_math":false,"creators":["Kilgour, Michael John Andrew"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Chemistry","school":null,"contributors":[],"advisors":["Segal, Dvira"],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-11","date_published":"2019-11","updated_at":"2026-07-27T21:28:05Z","subjects":["Buttiker probe","Feynman-Vernon path integral","Molecular junction","Nanodevices","Quantum heat machine","Quantum thermal transport"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1807/97509","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Segal, Dvira"]},{"key":"dc:contributor.department","label":"Department","values":["Chemistry"]},{"key":"dc:creator","label":"Author","values":["Kilgour, Michael John Andrew"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-11"]},{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-11-14T00:00:33Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-11-14T00:00:33Z"]},{"key":"dc:date.issued","label":"Date","values":["2019-11"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Buttiker probe","Feynman-Vernon path integral","Molecular junction","Nanodevices","Quantum heat machine","Quantum thermal transport"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1807/97509"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In this thesis, we pursue mechanisms in the nonequilibrium transport of charge and heat, to elucidate nanodevice operation, and explore fundamental theoretical questions. The thesis is divided into two parts. Part I explores in detail the role of incoherent effects on the charge transport behaviour of molecular junctions. Such effects, induced by molecular vibrations, solvent or other environmental effects, play a crucial role in many physical setups, but are difficult to simulate explicitly. We apply the Landauer-B\\\"uttiker probe technique, a phenomenological approach that incorporates incoherent effects at a low computational cost, and demonstrate the applicability of the technique by verifying that it captures a number of pertinent physical features, and achieves semi-quantitative agreement with experimental data. Going beyond this, we apply the probe method to a number of proposed physical setups. In stacked vs. alternating GC-rich ds-DNA, we find the even-odd effect in the experimentally observed conductance can be explained via a mixed coherent-incoherent transport mechanism. We find that in general, environmental interactions are destructive to the operation of molecular charge rectifiers, though in certain circumstances a weak rectifying behaviour might arise from many-body environmental effects. In Part II of this thesis we shift our focus to heat transport, and particularly the operation of quantum heat machines. We begin with a study of the role of so-called noise-induced coherences on the operation of a quantum absorption refrigerator. While in the past quantum coherences have usually been found to boost power in such setups, we observe a complete shutdown of the device when coherences survive to the nonequilibrium steady-state. We then extend our analysis, developing a general approach that one can use to more easily discover the role of coherences in quantum heat machines. We conclude with the development of a new numerically exact approach, the iterative full-counting statistics path integral (iFCSPI), which is suitable for simulations of heat transport in nanodevices. The iFCSPI allows the calculation of the cumulants of heat transport, as well as strong-coupling and non-Markovian effects, provided it can be converged."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:title","label":"Title","values":["Theory of Charge and Heat Transport Mechanisms in Nanodevices"]}]}],"canonical_facts":{"dc:contributor.advisor":["Segal, Dvira"],"dc:contributor.department":["Chemistry"],"dc:creator":["Kilgour, Michael John Andrew"],"dc:date":["2019-11"],"dc:date.accessioned":["2019-11-14T00:00:33Z"],"dc:date.available":["2019-11-14T00:00:33Z"],"dc:date.issued":["2019-11"],"dc:description.abstract":["In this thesis, we pursue mechanisms in the nonequilibrium transport of charge and heat, to elucidate nanodevice operation, and explore fundamental theoretical questions. The thesis is divided into two parts. Part I explores in detail the role of incoherent effects on the charge transport behaviour of molecular junctions. Such effects, induced by molecular vibrations, solvent or other environmental effects, play a crucial role in many physical setups, but are difficult to simulate explicitly. We apply the Landauer-B\\\"uttiker probe technique, a phenomenological approach that incorporates incoherent effects at a low computational cost, and demonstrate the applicability of the technique by verifying that it captures a number of pertinent physical features, and achieves semi-quantitative agreement with experimental data. Going beyond this, we apply the probe method to a number of proposed physical setups. In stacked vs. alternating GC-rich ds-DNA, we find the even-odd effect in the experimentally observed conductance can be explained via a mixed coherent-incoherent transport mechanism. We find that in general, environmental interactions are destructive to the operation of molecular charge rectifiers, though in certain circumstances a weak rectifying behaviour might arise from many-body environmental effects. In Part II of this thesis we shift our focus to heat transport, and particularly the operation of quantum heat machines. We begin with a study of the role of so-called noise-induced coherences on the operation of a quantum absorption refrigerator. While in the past quantum coherences have usually been found to boost power in such setups, we observe a complete shutdown of the device when coherences survive to the nonequilibrium steady-state. We then extend our analysis, developing a general approach that one can use to more easily discover the role of coherences in quantum heat machines. We conclude with the development of a new numerically exact approach, the iterative full-counting statistics path integral (iFCSPI), which is suitable for simulations of heat transport in nanodevices. The iFCSPI allows the calculation of the cumulants of heat transport, as well as strong-coupling and non-Markovian effects, provided it can be converged."],"dc:description.degree":["Ph.D."],"dc:identifier.uri":["http://hdl.handle.net/1807/97509"],"dc:subject":["Buttiker probe","Feynman-Vernon path integral","Molecular junction","Nanodevices","Quantum heat machine","Quantum thermal transport"],"dc:title":["Theory of Charge and Heat Transport Mechanisms in Nanodevices"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T21:28:05Z"}