P. A. Mello

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We develop a statistical theory describing quantum-mechanical scattering of a particle by a cavity when the geometry is such that the classical dynamics is chaotic. This picture is relevant to a variety of physical systems, ranging from atomic nuclei to mesoscopic systems and microwave cavities; the main application here is to electronic transport through(More)
The advantages and shortcomings of focused microwave-induced combustion (FMIC) for digestion of plant samples were studied. The effects of sample mass, absorbing solution, oxygen gas flow-rate, and time of reflux step on recoveries of major, minor and trace metals were systematically evaluated. Afterwards, Al, Ba, Ca, Co, Cr, Cu, Mg, Mn, Ni, Sr, V, and Zn(More)
We study the statistical properties of wave scattering in a disordered waveguide. The statistical properties of a "building block" of length deltaL are derived from a potential model and used to find the evolution with length of the expectation value of physical quantities. In the potential model the scattering units consist of thin potential slices,(More)
The capacitance of mesoscopic samples depends on their geometry and physical properties, described in terms of characteristic times scales. The resulting ac admittance shows sample to sample fluctuations. Their distribution is studied here—through a random-matrix model—for a chaotic cavity capacitively coupled to a backgate: it is observed from the(More)
A procedure for light and heavy crude oils digestion by microwave-induced combustion (MIC) is proposed for the first time for further rare earth elements (REE) determination by inductively coupled plasma mass spectrometry (ICP-MS) equipped with an ultrasonic nebulizer (USN). Samples of crude oil (API density of 10.8-23.5, up to 250 mg) were inserted in(More)
We develop a statistical theory that describes quantum-mechanical scattering of a particle by a cavity when the geometry is such that the classical dynamics is chaotic. This picture is relevant to a variety of physical systems, ranging from atomic nuclei to mesoscopic systems and microwave cavities; the main application to be discussed in this contribution(More)
A detailed analysis of the distribution of conductances P(g) of quasi-one-dimensional disordered wires in the metal-insulator crossover is presented. P(g) obtained from a Monte Carlo solution of the Dorokhov, Mello, Pereyra, and Kumar (DMPK) scaling equation is in full agreement with "tight-binding" numerical calculations of bulk disordered wires.(More)
The statistical theory of certain complex wave interference phenomena, like the statistical fluctuations of transmission and reflection of waves, is of considerable interest in many fields of physics. In this article we shall be mainly interested in those situations where the complexity derives from the quenched randomness of scattering potentials, as in(More)
We propose a model to describe the statistical properties of wave scattering through a classically chaotic cavity in the presence of surface absorption. Experimentally, surface absorption could be realized by attaching an "absorbing patch" to the inner wall of the cavity. In our model, the cavity is connected to the outside by a waveguide with N open modes(More)
We show that the study of the statistical properties of the scattering matrix S for quantum chaotic scattering in the presence of direct processes (characterized by S 6= 0, S being the average S matrix) can be reduced to the simpler case where direct processes are absent (S = 0). Our result is verified with a numerical simulation of the two-energy(More)