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J. M. A. Figueiredo

Publications and source records attributed to J. M. A. Figueiredo.

6 recordsLinked to original sources

Evidence for undamped waves on ohmic materials

The propagation of electromagnetic fields in matter has been the subject of intensive studies since the discovery of its rich dynamics. Impedance measurements are one most used technique available to study material properties as well as electromagnetic devices and circuits. This way, novelties on device construction and circuit technology associated to new material properties and/or unusual field dynamics generally rely on results supported by impedance data. Recent advances on nanostructured materials explore astounding molecular properties derived from nanoscale levels and apply them to studies foucused on the generation of new devices. Accordingly, properties inherent to quantum dynamics can also generate unusual circuit elements, not included on the former development of the electromagnetic theory. On same footings, advances in field dynamics could also determine the advent of new technologies, producing immediate impact on our everyday life. In this work we present the results obtained by measuring the impedance of single spires and coils of specific geometry in the MHz range. They demonstrate that a new passive circuit element was found, which bears out the existence of an as yet unobserved propagation mode of the electromagnetic fields in matter. Our results also indicates that this effect is more evident using carbon made spires.

physics.gen-ph↗

First principles quantum Monte Carlo

Present quantum Monte Carlo codes use statistical techniques adapted to find the amplitude of a quantum system or the associated eigenvalues. Thus, they do not use a true physical random source. It is demonstrated that, in fact, quantum probability admits a description based on a specific class of random process at least for the single particle case. Then a first principle Monte Carlo code that exactly simulates quantum dynamics can be constructed. The subtle question concerning how to map random choices in amplitude interferences is explained. Possible advantages of this code in simulating single hit experiments are discussed.

quant-ph↗

Quantum Mechanics without amplitudes

Amplitudes are the major logical object in Quantum Theory. Despite this fact they presents no physical reality and in consequence only observables can be experimetally checked. We discuss the possibility of a theory of Quantum Probabilities capable of give full account to quantum phenomena. Advanteges of this formulation are the evidence of physical processes not described by the orotodox formulation using amplitudes and the possibility of a full algoritimization of Quantum Mechanics.

quant-ph↗

Games with Quantum Analogues

A new class of stochastic variables, governed by a specifice set of rules, is introduced. These rules force them to loose some properties usually assumed for this kind of variables. We demonstrate that stochastic processes driven by these random sources must be described using an probability amplitude formalism in a close resemblance to Quantum Theory. This fact shows, for the first time, that probability amplitudes are a general concept and is not exclusive to the formalism of Quantum Theory. Application of these rules to a noisy, one-dimensional motion, leds to a probability structure homomorphic to Quantum Mechanics.

quant-ph↗

Quantum Dynamics as a Stochastic Process

We study the classical motion of a particle subject to a stochastic force. We then present a perturbative schema for the associated Fokker-Planck equation where, in the limit of a vanishingly small noise source, a consistent dynamical model is obtained. The resulting theory is similar to Quantum Mechanics, having the same field equations for probability measures, the same operator structure and symmetric ordering of operators. The model is valid for general electromagnetic interaction as well as many body systems with mutual interactions of general nature.

quant-ph↗

Quantum Dynamics in Stochastic Mechanics

A study of the non-dissipative Brownian motion in vacuum is presented. The noise source associated to the stochastic process assumed in this work is vacuum fluctuations of some quantum field capable of interact with a massive particle. For the associated Fokker-Planck equation we do a perturbation theory which has terms presenting dynamics similar to that satisfied by the probability amplitude in Quantum Theory even though the physical interpretation be classical. In particular classical observables present expected values that coincide with those calculated using Quantum Mechanics.

physics.class-ph↗