Um modelo esquemático e um modelo realistico para tunelamento coerente em poco duplo

• Ano de defesa: 2006
• Autor(a) principal: Gabriela Barreto Lemos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: tunelamento coerente em poco duplo; Tunelamento (Física); Física
• Link de acesso: http://hdl.handle.net/1843/IACO-6W9SBQ

We present two examples of tunneling in double well potentials. Therst is a study of the localization in a dissipative one-particle system bymeans of an analogy with a spin-1/2 system in a uniform magnetic eld.The second example is an investigation of the tunneling process of a Bose-Einstein Condensate in a double well potential from the point of view ofa many body Hamiltonian. Although the two-mode model for the processis not realistic for large enough number of particles (N 200), for certaininitial conditions, it points out a completely dierent explanation for thenon-observation of tunneling from that given in Michael Albiez et al, Phys.Rev. Lett. 95, 010402 (2005). We observe a \phase transition" related to spectral properties of the Hamiltonian and the initial conditions which, for large enough initial population imbalance, presents occupation probabilitiesconcentrated in doublets.