Cumulants
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. EstatÃstica de contagem de carga e efeitos de interferÃncia em sistemas mesoscÃpicos
In this thesis we presented a detailed study about full counting statistics of transmitted charge and accumulated phase and the quantum interference corrections to the average conductance and the average shot-noise power in non-ideal ballistic chaotic cavities. In the theoretical analysis of this mesoscopic system, we obtained analytical expressions for the
Publicado em: 2009
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2. MÃtodos estatÃsticos multi-percursos para a identificaÃÃo cega de canais da fonte de aplicaÃÃes Ãs comunicaÃÃes sem fio / High-order statistical methods for blind channel identification and source detection with applications to wireless communications
Les systÃmes de tÃlÃcommunications modernes exigent des dÃbits de transmission trÃs ÃlevÃs. Dans ce cadre, le problÃme dâidentification de canaux est un enjeu majeur. Lâutilisation de techniques aveugles est dâun grand intÃrÃt pour avoir le meilleur compromis entre un taux binaire adÃquat et la qualità de lâinformation rÃcupÃrÃe. En utilis
Publicado em: 2008
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3. HBT shape analysis with q -cumulants
Taking up and extending earlier suggestions, we show how two- and three-dimensional shapes of second-order HBT correlations can be described in a multivariate Edgeworth expansion around Gaussian ellipsoids, with expansion coefficients, identified as the cumulants of pair momentum difference q , acting as shape parameters. Off-diagonal terms dominate both the
Brazilian Journal of Physics. Publicado em: 2007-09
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4. Correlation of the ghost and the quark in the lattice landau gauge QCD
Effects of the quark field on the ghost propagator of the lattice Landau gauge are investigated by using the unquenched SU(3) configurations produced by the MILC collaboration and compared with quenched gauge configurations of SU(2) first copy of the overrelaxation gauge fixing, the parallel tempering (PT) gauge fixing and quenched SU(3) 56(4) configurations
Brazilian Journal of Physics. Publicado em: 2007-03
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5. Monte Carlo study of the metamagnet Ising model in a random and uniform field
Monte Carlo simulation has been used to determine the phase diagram of a metamagnet Ising model in the presence of a random and uniform magnetic field. The model consists of a spin-1/2 metamagnet in which the nearest neighbor and next nearest neighbor spin interactions are antiferromagnetic (J1 < 0) and ferromagnetic (J2 > 0), respectively. We used a bimodal
Brazilian Journal of Physics. Publicado em: 2006-09
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6. Transporte em nanoestruturas: mÃtodos de movimento Browniano e teoria de circuitos
The results presented in this thesis can be divided into two parts. In the first one we study a class of Brownian motion ensembles (BME) obtained from the general theory of matricial Markovian stochastic processes of random matrix theory. The ensembles are characterized by a Fokker-Planck equation and are closely related to Hamiltonians of Calogero-Sutherlan
Publicado em: 2006
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7. AnÃlise diagramÃtica para cavidades caÃticas de barreira dupla : equivalÃncia com teoria quÃntica de circuitos
In this work we derive a set of coupled non-linear algebraic equations for the asymptotics of the Poisson kernel distribution, describing the statistical properties of a two-terminal double-barrier chaotic billiar (or ballistic quantum dot). The equations are calculated from a diagrammatic technique [P. W. Brouwer e C. W. Beenakker, J. Math. Phys. 37, 4904 (
Publicado em: 2005
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8. Processos de polimerização e transição de colapso em polímeros ramificados. / Polymerization processes and collapse transition of branched polymers.
The phase diagram and the tricritical point of a collapsing lattice animal are studied through an extended series expansion of the isothermal compressibility KT on a square lattice. As a function of the variables x (fugacity) and y = e1/T (T is the reduced temperature), this series KT is investigated using the partial differential approximants technique. The
Publicado em: 1997
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9. Expansão em cumulantes para o Modelo de Anderson Periodico
The diagrammatic expansion in cumulants that was employed by Hubbard to study his model of a narrow band of strongly correlated electrons was extended to the Periodic Anderson Model (PAM). The model was also extended by considering localized electronic states with an arbitrary scheme of energy levels: this extension would be useful to study intermediate vale
Publicado em: 1994
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10. Definition and Estimation of Higher-Order Gene Fixation Indices
Fixation indices summarize the associations between genes that arise from the joint effects of inbreeding and selection. In this paper, fixation indices are derived for pairs, triplets and quadruplets of genes at a single multiallelic locus. The fixation indices are obtained by dividing cumulants by constants; the cumulants describe the statistical distribut
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11. Genetic and Statistical Analyses of Strong Selection on Polygenic Traits: What, Me Normal?
We develop a general population genetic framework for analyzing selection on many loci, and apply it to strong truncation and disruptive selection on an additive polygenic trait. We first present statistical methods for analyzing the infinitesimal model, in which offspring breeding values are normally distributed around the mean of the parents, with fixed va
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12. Detection of weak synaptic interactions between single Ia afferent and motor-unit spike trains in the decerebrate cat.
1. Spike trains from identified single Ia afferents from soleus and lateral gastrocnemius muscles were recorded (while 'in continuity' with the spinal cord) simultaneously with single-motor-unit EMG spike trains from the same muscles in decerebrate cats. 2. A total of 143 Ia afferent-motor-unit pairs were examined for the presence of correlated activity betw