Wigner Function
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Recognition of heart sound based on distribution of Choi-Williams
IntroductionTo realize noninvasive diagnosis and early diagnosis of coronary heart disease, the study proposes a new time-frequency method for analyzing heart sound signals. This method is based on Choi-Williams Distribution (CWD).MethodsCWD distribution is developed and modified from Wigner Ville distribution (WVD). To solve the problem of cross-term interf
Res. Biomed. Eng.. Publicado em: 29/09/2015
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2. Estudo e geração de estados não clássicos em nanocircuitos: propriedades e aplicações / Study and generation of nonclassical states in nanocircuits: properties and aplications
In this work we used an arrangement consisting of Cooper pairs (Cooper Pair Box, CPB) interacting with a nanomechanical Resonator (NR) for various studies: to produce controlable holes in the statistical distribution of excitations of the NR, for resonant and non-resonant cases; to study the evolution of the entropy and the inversion of excitations, includin
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/03/2012
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3. Estudo e geração de estados não clássicos em nanocircuitos: propriedades e aplicações / Study and generation of nonclassical states in nanocircuits: properties and aplications
Neste trabalho utilizamos um arranjo formado de pares de Cooper (Cooper Pair Box, CPB) interagindo com um Ressoador Nanomecânico (NR), para vários estudos: cavar buracos na distribuição estatística de excitações do Ressoador, nos casos ressonante e não ressonante; estudar a evolução da entropia e da inversão de excitação, incluindo perdas no CPB
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/03/2012
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4. Study of the influence of structural defects in the properties of carbon nanotube / Estudo da influência de defeitos estruturais nas propriedades de nanotubos de carbono
We have investigated the influence of defects on structural, electronic and mechanical properties of single-walled carbon nanotubes (SWCNT), bundles of nanotubes and multi-walled carbon nanotubes (MWCNT). All our results were obtained with the first principles theory of total energy - Density Functional theory (DFT). We have investigated the structural prope
Publicado em: 2009
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5. Dimer models on planar lattice. Transfer matrix and soutions by fermion representation / Modelos de dímeros em redes planas. Matriz de transferência e soluções por meio da representação de férmions
We solve the dimer model on two different planar lattices, the 4-8 lattice and the honeycomb lattice. In the dimer model on the 4-8 lattice there is a phase transition of the (two-dimensional) Ising type; on the honeycomb lattice there is a phase transition known as 3/2. After defining the model we show that the calculation of the partition function can be f
Publicado em: 2009
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6. DISSIPAÇÃO EM MODOS ACOPLADOS
The implementation of processes of Quantum Computation as well as the transmission and quantum information control in realistic physical systems, must take in account the effects of the coupling of the systems with the environment, represented by thermal reservoirs. In this work it is considered the study of the effects of the environment in the quantum prop
Publicado em: 2007
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7. Propriedades fisicas de operações gaussianas sobre estados gaussianos emaranhados / Physical properties of gaussian operations over entangled gaussian states
We study quantum Gaussian states and the physical properties associated to operations over such class of states, which preserve the respective Gaussian nature. General properties of global covariance matrices representing two-mode bipartite Gaussian states can be decomposed into properties of local covariance matrices and their Schur complements. We demonstr
Publicado em: 2007
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8. Operador Deslocamento Condicional: Geração de Estados e Medida da Função de Wigner / Conditional Operator Shift: Generation of states and the Wigner Function Measure
Apresentamos uma proposta factível para a construção do operador deslocamento condicional usando um meio Kerr entre dois divisores de feixes alimentados por estados coerentes altamente excitados. O dispositivo permite implementar a geração de uma nova classe de estados do campo eletromagnético quantizado (superposições de estados arbitrários com est
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/03/2006
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9. Operador Deslocamento Condicional: Geração de Estados e Medida da Função de Wigner / Conditional Operator Shift: Generation of states and the Wigner Function Measure
Apresentamos uma proposta factível para a construção do operador deslocamento condicional usando um meio Kerr entre dois divisores de feixes alimentados por estados coerentes altamente excitados. O dispositivo permite implementar a geração de uma nova classe de estados do campo eletromagnético quantizado (superposições de estados arbitrários com est
Publicado em: 2006
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10. Decoherence and Loschmidt echoes: quantum against classical
Some recent theoretical results on the stability of quantum dynamics against perturbations of the Hamiltonian - the so-called Loschmidt echoes and their relation to various decoherence measures are reviewed. We show that the representation of Loschmidt echoes in terms of the Wigner function can explain some seemingly paradoxical behavior of the quantum-class
Brazilian Journal of Physics. Publicado em: 2005-06
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11. Classical trajectories and quantum field theory
The density matrix and the Wigner function formalism requires the doubling of the degrees of freedom in quantum mechanics (QM) and quantum field theory (QFT). The doubled degrees of freedom play the role of the thermal bath or environment degrees of freedom and are entangled with the system degrees of freedom. They also account for quantum noise in the fluct
Brazilian Journal of Physics. Publicado em: 2005-06
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12. Molecular dynamics simulations of two-dimensional clusters of charges
We study structural and spectral properties of finite classical systems of N two-dimensional charged particles,confined by a parabolic potential µ, and interacting via inverse power-law potentials µ 1/r n' . Molecular dynamics simulations are performed for different cluster sizes (N = 30 to 230) and n, n' values 1, 2, 3 and 10. We also analyze the phase tr
Brazilian Journal of Physics. Publicado em: 2004-06