Dicke Model
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. Sistema mecânico como sonda de uma transição de fase quântica
O modelo de Dicke descreve um sistema contendo um conjunto de átomos acoplados a um modo do campo eletromagnético. Uma das características desse modelo é que ele exibe uma transição de fase quântica de segunda ordem. Neste trabalho tivemos como principal objetivo estudar a transição de fase quântica presente nesse modelo através de uma sonda mecâ
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/03/2011
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2. Quantum entanglement in a many-body system exhibiting multiple quantum phase transitions
We investigate the quantum entanglement-related features of the many-body model of Plastino and Moszkowski [N. Cimento 47 (1978) 470]. This is an exactly solvable N-body, SU2 two-level model exhibiting several quantum phase transitions. We show that these transitions happen to be also entanglement-transitions associated with different many-body Dicke states.
Brazilian Journal of Physics. Publicado em: 2009-08
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3. Phase space solutions in scalar-tensor cosmological models
An analysis of the solutions for the field equations of generalized scalar-tensor theories of gravitation is performed through the study of the geometry of the phase space and the stability of the solutions, with special interest in the Brans-Dicke model. Particularly, we believe to be possible to find suitable forms of the Brans-Dicke parameter w and potent
Brazilian Journal of Physics. Publicado em: 2005-12
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4. Aplicação das funções de quase-probabilidade no estudo da dinamica de emaranhamento
Entanglement dynamics of two ideal bipartites systems is analyzed using reduced linear entropy and quasiprobability distribution functions in the semiclassical regime.Two models are studied: the quartic bidimensional oscillator and the Dicke ?s Maser model. The first one describes the propagation of two monochromatic field modes in a Kerr medium, and the sec
Publicado em: 2003
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5. Dinamica de sistemas quanticos : atomos em cavidades de ions aprisionados
In this thesis we studied the dynamics of two quantum systems: atoms in a cavity and trapped ions. For atoms in a cavity ( QED ) , we studied the dynamics of field prepared in a superposition of coherent states and a statistical mixture. In this system, using a Intensity-Dependence Jaynes-Cummings model (DNJCM) we discuss some aspects of the dynamics of atom
Publicado em: 2002
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6. An analysis of helium primordial nucleosynthesis with a variable cosmological coupling
The synthesis of helium in the early Universe depends on many input parameters, including the value of the gravitational coupling during the period when the nucleosynthesis takes place. We compute the primordial abundance of helium as function of the gravitational coupling, using a semi-analytical method, in order to track the influence of G in the primordia
Brazilian Journal of Physics. Publicado em: 2001-12
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7. Manifestações do caos no modelo do Maser de Dicke
We study the effects of nonintegrability in the Dicke Maser Model by observing the modifications in the patterns of distribution of expectation values in the energy eigenstates of some selected operators plotted against energy eigenvalues. The semiclassical density of states and the mean values of observables in the microcanonical ensemble are obtained and c
Publicado em: 1995