Light-atom interaction: mean-field approach and intensity fluctuations
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://doi.org/10.11606/T.76.2019.tde-08052019-093257 |
Resumo: | In this thesis, we investigate the coherent scattering of light propagating in a random medium. We are interested in phenomena like the super- and subradiance and Anderson localization that are related to waves interferences and spatial disorder. However, the fundamental difference between subradiance and Anderson localization still needs to be clarified. This thesis gives new elements for the understanding of these phenomena and we present a new method to observe Anderson localization. A mean-field model that does not contain disorder is developed, and we show that super- and subradiance do not require disorder whereas Anderson localization does. In this theoretical work, the coupling between the light and many atoms is reduced to a coupling matrix between the atoms by tracing over the degrees of freedom of the light, which results in a linear problem for the atomic dipoles. The study of the eigenvalues and eigenmodes of this matrix then allows to determine the super- and subradiant modes, and to probe the Anderson localization phase transition with a scaling analysis. Furthermore, the link to the experiment is realized by showing that the intensity fluctuations present an increase at the localization transition. The system is studied in the steady-state regime when the medium is continuously charged by a laser until reaches a stationary regime, and the decay dynamics, when the laser is switched off, so the cloud releases the energy stored. Finally, we present a preliminary work that shows that the diagonal disorder might be a good strategy to reach Anderson localization. |
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info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis Light-atom interaction: mean-field approach and intensity fluctuations Interação luz-átomo: abordagem de campo médio e flutuações de intensidade 2019-01-24Romain Pierre Marcel BachelardCelso Jorge Villas BôasRobin KaiserFrancisco Ednilson Alves dos SantosThierry Marcelino Passerat de SilansFlorent André Julien CottierUniversidade de São PauloFísicaUSPBR Anderson localization Átomos frios Cold atoms Cooperative effects Efeitos cooperativos Localização de Anderson Super- and subradiance Super- e subradiância In this thesis, we investigate the coherent scattering of light propagating in a random medium. We are interested in phenomena like the super- and subradiance and Anderson localization that are related to waves interferences and spatial disorder. However, the fundamental difference between subradiance and Anderson localization still needs to be clarified. This thesis gives new elements for the understanding of these phenomena and we present a new method to observe Anderson localization. A mean-field model that does not contain disorder is developed, and we show that super- and subradiance do not require disorder whereas Anderson localization does. In this theoretical work, the coupling between the light and many atoms is reduced to a coupling matrix between the atoms by tracing over the degrees of freedom of the light, which results in a linear problem for the atomic dipoles. The study of the eigenvalues and eigenmodes of this matrix then allows to determine the super- and subradiant modes, and to probe the Anderson localization phase transition with a scaling analysis. Furthermore, the link to the experiment is realized by showing that the intensity fluctuations present an increase at the localization transition. The system is studied in the steady-state regime when the medium is continuously charged by a laser until reaches a stationary regime, and the decay dynamics, when the laser is switched off, so the cloud releases the energy stored. Finally, we present a preliminary work that shows that the diagonal disorder might be a good strategy to reach Anderson localization. Nesta tese, investigamos o espalhamento coerente de luz propagando em um meio aleatório. Estamos interessados em fenômenos como superradiância, subradiância e localização de Anderson, os quais estão relacionados com interferências de ondas e desordem espacial. No entanto, as diferenças fundamentais entre subradiância e localização de Anderson ainda precisam ser esclarecidas. Esta tese traz novos elementos na compreensão destes fenômenos e apresentamos um novo método para observar a localização de Anderson. Neste trabalho teórico, estudamos os autovalores e os automodos de uma matriz de acoplamento que permite extrair modos super- e subradiantes, e exibem uma transição de fase de localização de Anderson através de uma análise de escalamento. Além disso, a conexão com o experimento é feita através da intensidade irradiada pela nuvem em todas as direções. Distinguimos dois casos: o regime de estado estacionário, quando o meio é continuamente excitado por um laser e alcança um regime estacionário; e o caso dinâmico, onde o laser é desligado e a nuvem libera a energia armazenada. Desenvolvemos um modelo de campo médio que não inclui desordem, e mostramos que super- e subradiância não precisam da desordem para existir, ao contrário da localização de Anderson. Mostramos também que podemos observar uma transição de fase de localização de Anderson na estatística da intensidade. Finalmente, apresentamos um trabalho preliminar que mostra que a desordem diagonal pode ser uma boa estratégia para alcançar a localização de Anderson. https://doi.org/10.11606/T.76.2019.tde-08052019-093257info:eu-repo/semantics/openAccessengreponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USP2023-12-21T18:27:37Zoai:teses.usp.br:tde-08052019-093257Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212023-12-22T12:19:51.224040Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.en.fl_str_mv |
Light-atom interaction: mean-field approach and intensity fluctuations |
dc.title.alternative.pt.fl_str_mv |
Interação luz-átomo: abordagem de campo médio e flutuações de intensidade |
title |
Light-atom interaction: mean-field approach and intensity fluctuations |
spellingShingle |
Light-atom interaction: mean-field approach and intensity fluctuations Florent André Julien Cottier |
title_short |
Light-atom interaction: mean-field approach and intensity fluctuations |
title_full |
Light-atom interaction: mean-field approach and intensity fluctuations |
title_fullStr |
Light-atom interaction: mean-field approach and intensity fluctuations |
title_full_unstemmed |
Light-atom interaction: mean-field approach and intensity fluctuations |
title_sort |
Light-atom interaction: mean-field approach and intensity fluctuations |
author |
Florent André Julien Cottier |
author_facet |
Florent André Julien Cottier |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Romain Pierre Marcel Bachelard |
dc.contributor.referee1.fl_str_mv |
Celso Jorge Villas Bôas |
dc.contributor.referee2.fl_str_mv |
Robin Kaiser |
dc.contributor.referee3.fl_str_mv |
Francisco Ednilson Alves dos Santos |
dc.contributor.referee4.fl_str_mv |
Thierry Marcelino Passerat de Silans |
dc.contributor.author.fl_str_mv |
Florent André Julien Cottier |
contributor_str_mv |
Romain Pierre Marcel Bachelard Celso Jorge Villas Bôas Robin Kaiser Francisco Ednilson Alves dos Santos Thierry Marcelino Passerat de Silans |
description |
In this thesis, we investigate the coherent scattering of light propagating in a random medium. We are interested in phenomena like the super- and subradiance and Anderson localization that are related to waves interferences and spatial disorder. However, the fundamental difference between subradiance and Anderson localization still needs to be clarified. This thesis gives new elements for the understanding of these phenomena and we present a new method to observe Anderson localization. A mean-field model that does not contain disorder is developed, and we show that super- and subradiance do not require disorder whereas Anderson localization does. In this theoretical work, the coupling between the light and many atoms is reduced to a coupling matrix between the atoms by tracing over the degrees of freedom of the light, which results in a linear problem for the atomic dipoles. The study of the eigenvalues and eigenmodes of this matrix then allows to determine the super- and subradiant modes, and to probe the Anderson localization phase transition with a scaling analysis. Furthermore, the link to the experiment is realized by showing that the intensity fluctuations present an increase at the localization transition. The system is studied in the steady-state regime when the medium is continuously charged by a laser until reaches a stationary regime, and the decay dynamics, when the laser is switched off, so the cloud releases the energy stored. Finally, we present a preliminary work that shows that the diagonal disorder might be a good strategy to reach Anderson localization. |
publishDate |
2019 |
dc.date.issued.fl_str_mv |
2019-01-24 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://doi.org/10.11606/T.76.2019.tde-08052019-093257 |
url |
https://doi.org/10.11606/T.76.2019.tde-08052019-093257 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
Universidade de São Paulo |
dc.publisher.program.fl_str_mv |
Física |
dc.publisher.initials.fl_str_mv |
USP |
dc.publisher.country.fl_str_mv |
BR |
publisher.none.fl_str_mv |
Universidade de São Paulo |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
_version_ |
1794502568151351296 |