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Master's Dissertation
DOI
10.11606/D.76.2001.tde-24062008-133522
Document
Author
Full name
Wânius José Garcia da Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2001
Supervisor
Committee
Marcassa, Luis Gustavo (President)
Cruz, Flávio Caldas da
Napolitano, Reginaldo de Jesus
Title in Portuguese
Estudo de taxas de perdas em sistemas heteronucleares
Keywords in Portuguese
Armadilha magneto-óptica
Colisões frias heteronucleares
Condesado de Bose-Einstein
Escape radiativo
Mudança de estrutura fina
Abstract in Portuguese
Uma análise dos processos colisionais homonucleares e heteronucleares, responsáveis por perdas em uma armadilha magneto-óptica, foi realizada neste trabalho. Resultados experimentais inéditos para as taxas de perdas, no sistema Rb-Cs, foram obtidos. Os dados experimentais em conjunto com os resultados do modelo sugerem que o processo de escape radiativo é dominante. O modelo utilizado é muito sensível à profundidade da armadilha, a qual depende de outros parâmetros (intensidade, dessintonia, gradiente de campo magnético, etc.). A colaboração com pesquisadores italianos possibilitou uma análise mais detalhada das taxas de perdas heteronucleares em outras regiões de intensidade. Estudamos a dependência das taxas heteronucleares com a razão das massas do par atômico, e uma razoável concordância foi observada. O estudo de processos colisionais em armadilhas magneto-ópticas é importante na obtenção do condensado de BoseEinstein com duas espécies atômicas distintas, e também em experiências de espectroscopia fotoassociativa.
Title in English
Trap loss in a two-species Rb-Cs magneto-optical trap
Keywords in English
Bose-Einstein condensates
Heteronuclear cold collisions
Hyperfine change collision
Magneto optical trap
Radiative escape
Abstract in English
In this work, we had investigated the heteronuclear trap loss rate in a two-species Rb-Cs magneto-optical trap. The experimental results suggest that radiative escape is the main collisional process responsible for heteronuclear losses. An addapted Gallagher - Pritchard model is compared with the data. The model is very sensitive to the trap depth, which depends on the trap parameters (intensity, detuning, magnetic - field gradient, etc.) This observation is also supported by experimental results from a Pisa' group. We have compared experimental of heteronuclear rates as a function of the masses ratio of the atomic pair with the model, and a reasonable agreement is observed. These studies are relevant for high resolution atomic / molecular spectroscopy, and for the production of mixed - species Bose-Einstein condensates.
 
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WaniusSilva_M.pdf (2.67 Mbytes)
Publishing Date
2008-07-04
 
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