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Francisco Caruso

Publications and source records attributed to Francisco Caruso.

36 records · Page 2Linked to original sources
arXiv2018

How the inter-electronic potential Ansätze affect the bound state solutions of a planar two-electron quantum dot model

The model of a two-electron quantum dot, confined to move in a two dimensional flat space, in the presence of an external harmonic oscillator potential, is revisited for a specific purpose. Indeed, eigenvalues and eigenstates of the bound state solutions are obtained for any oscillation frequency considering both the $1/r$ and $\ln r$ Ansätze for inter-electronic Coulombic-like potentials in 2$D$. Then, it is pointed out that the significative difference between measurable quantities predicted from these two potentials can shed some light on the problem of space dimensionality as well as on the physical nature of the potential itself.

quant-ph↗
arXiv2017

Specific heats of degenerate ideal gases

From arguments based on Heisenberg's uncertainty principle and Pauli's exclusion principle, the molar specific heats of degenerate ideal gases at low temperatures are estimated, giving rise to values consistent with the Nerst-Planck Principle (third law of Thermodynamics). The Bose-Einstein condensation phenomenon based on the behavior of specific heat of massive and non-relativistic boson gases is also presented.

physics.gen-ph↗
arXiv2016

Life and space dimensionality: A brief review of old and new entangled arguments

A general sketch on how the problem of space dimensionality depends on anthropic arguments is presented. Several examples of how life has been used to constraint space dimensionality (and vice-versa) are reviewed. In particular, the influences of three-dimensionality in the solar system stability and the origin of life on Earth are discussed. New constraints on space dimensionality and on its invariance in very large spatial and temporal scales are also stressed.

physics.hist-ph↗
arXiv2015

O Átomo

The article is an historical overview of some of the major contributions from different areas of Science with which, for centuries, it has been built up a scientific, sound and consistent vision of the atom. Some experiments that led us to a number of evidence about the composite nature of the atom are highlighted.

physics.hist-ph↗
arXiv2015

Causa Efficiens versus Causa Formalis: origens da discussão moderna sobre a dimensionalidade do espaço

Metascientific criteria used for explaining or constraining physical space dimensionality and their historical relationship to prevailing causal systems are discussed. The important contributions by Aristotle, Kant and Ehrenfest to the dimensionality of space problem are considered and shown to be grounded on different causal explanations: {\it causa materialis} for Aristotle, {\it causa efficiens} for young Kant and an ingenious combination of {\it causa efficiens} and {\it causa formalis} for Ehrenfest. The prominent and growing rôle played by {\it causa formalis} in modern physical approaches to this problem is emphasized.

physics.hist-ph↗
arXiv2015

On Kant's first insight into the problem of space dimensionality and its physical foundations

In this article it is shown that a careful analysis of Kant's "Thoughts on the True Estimation of Living Forces" leads to a conclusion that does not match the usually accepted interpretation of Kant's reasoning in 1747, according to which the Young Kant supposedly establishes a relationship between the tridimensionality of space and Newton's law of universal gravitation. Indeed, it is argued that this text does not yield a satisfactory explanation of space dimensionality, actually restricting itself to justify the tridimensionality of extension.

physics.hist-ph↗
arXiv2014

Dimensionalidade do espaço ou da extensão: nota sobre a contribuição do jovem Kant

In this article, we present new comments to the article On Kant's First Insight Into The Problem of Space Dimensionality and Its Physical Foundations. In particular, we discuss how the space concept is designed in the first writing of Kant. In this work, dated 1747, the young Kant proposes to discuss how we can justify the three-dimensionality of space . Although he explicitly anticipates that this will demonstrate throughout the text, in fact, he merely relate the dimensionality of the extension to the law of gravitation. Anyway, this speculation went beyond Kant's Philosophy and had impact on the modern discussion about dimensionality of space. Indeed, from the point of view of physics, Kant's conjecture can be understood in the context of formulation of classical fields of Newtonian theory of gravitation. However, some philosophical points that led the young Kant did not succeed in proving the three-dimensional nature of space still deserve attention. This article is aimed to discuss them.

physics.hist-ph↗
arXiv2014

Ensaio sobre a unidimensionalidade do tempo

Some ideas aimed to understand that time is one-dimensional are briefly reviewed. Some attempts to construct theories in varieties with more spatial and temporal components are presented. It is discussed, from the epistemological point of view, which path can be taken to try to "prove" the one-dimensionality of time (or the three-dimensionality of space) from these generalized theories.

physics.hist-ph↗
arXiv2014

Sobre a viagem de Enrico Fermi ao Brasil em 1934

Enrico Fermi was one of the greater physicists of the XX century. In 1934, he gave several lectures in Brazil. Invited by Theodoro Ramos to work in São Paulo, he preferred to stay in Rome and went to the USA in 1938. However, Fermi recommended Gleb Wataghin to come in his place. Wataghin made history in Brazil, becoming one of the first Professors of the future São Paulo University. Besides his relevance to the History of Science, Fermi eventually leaved an indelible mark on the creation and institutionalization of national scientific research due to the indication of Wataghin. Despite this fact, very little is known about Fermi's trip to Brazil. This work tries to reconstruct the fullest possible steps of the famous Italian physicist in our lands.

physics.hist-ph↗
arXiv2014

Is There Flavour Independence in Tensor Glueball Decays?

The flavour independence hypothesis for (tensor) glueball decays into exclusive final states is not ruled out by the existing data. A new methodology for testing its validity and accuracy is proposed in the framework of a particular mixing scheme. As an important consequence of our analysis, a relative factor of the order of 10 must be experimentally observed for the ratio $Γ(Θ\rightarrow K\bar{K})Γ(Θ\rightarrow ππ)$, if flavour independence indeed is valid.

hep-ph↗
arXiv2013

On the Dirac Monopole Mass Scale

It is shown, by a semi-classical argument, that the Dirac charge quantization is still valid in the (classical) Born-Infeld electromagnetic theory. Then it is possible to calculate Dirac's monopole mass in the framework of this theory, which is not possible in Maxwell's theory. The existence of an upper limit for the field intensities in this theory plays an important role in this proof.

physics.gen-ph↗
arXiv2013

Note on the Existence of Hydrogen Atoms in Higher Dimensional Euclidean Spaces

The question of whether hydrogen atoms can exist or not in spaces with a number of dimensions greater than 3 is revisited, considering higher dimensional Euclidean spaces. Previous results which lead to different answers to this question are briefly reviewed. The scenario where not only the kinematical term of Schrödinger equation is generalized to a D-dimensional space but also the electric charge conservation law (expressed here by the Poisson law) should actually remains valid is assumed. In this case, the potential energy in the Schrödinger equation goes like 1/r^{D-2}. The lowest quantum mechanical bound states and the corresponding wave functions are determined by applying the Numerov numerical method to solve Schrödinger's eigenvalue equation. States for different angular momentum quantum number (l = 0; 1) and dimensionality (5 \leq D \leq 10) are considered. One is lead to the result that hydrogen atoms in higher dimensions could actually exist. For the same range of the dimensionality D, the energy eigenvalues and wave functions are determined for l = 1. The most probable distance between the electron and the nucleus are then computed as a function of D showing the possibility of tiny bound states.

quant-ph↗
arXiv2012

On the Physical Problem of Spatial Dimensions: An Alternative Procedure to Stability Arguments

Why is space 3-dimensional? The first answer to this question, entirely based on Physics, was given by Ehrenfest, in 1917, who showed that the stability requirement for $n$-dimensional two-body planetary system very strongly constrains space dimensionality, favoring 3-d. This kind of approach will be generically called "stability postulate" throughout this paper and was shown by Tangherlini, in 1963, to be still valid in the framework of general relativity as well as for quantum mechanical hydrogen atom, giving the same constraint for space-dimensionality. In the present work, before criticizing this methodology, a brief discussion has been introduced, aimed at stressing and clarifying some general physical aspects of the problem of how to determine the number of space dimensions. Then, the epistemological consequences of Ehrenfest's methodology are critically reviewed. An alternative procedure to get at the proper number of dimensions, in which the stability postulate (and the implicit singularities in three-dimensional physics) are not an essential part of the argument, is proposed. In this way, the main epistemological problems contained in Ehrenfest's original idea are avoided. The alternative methodology proposed in this paper is realized by obtaining and discussing the $n$-dimensional quantum theory as expressed in Planck's law, de Broglie relation and the Heisenberg uncertainty relation. As a consequence, it is possible to propose an experiment, based on thermal neutron diffraction by crystals, to directly measure space dimensionality. Finally the distinguished role of Maxwell's electromagnetic theory in the determination of space dimensionality is stressed.

physics.hist-ph↗
arXiv2011

Zero-frequency magnetic fluctuations in homogeneous cosmic plasma revisited

Magnetic fluctuations in a non-magnetized gaseous plasma is revisited and calculated without approximations, based on the fluctuation-dissipation theorem. It is argued that the present results are qualitative and quantitative different form previous one based on the same theorem. In particular, it is shown that it is not correct that the spectral intensity does not vary sensitively with $k_{cut}$. Also the simultaneous dependence of this intensity on the plasma and on the collisional frequencies are discussed.

astro-ph.CO↗
arXiv2008

The Cosmic Microwave Background Spectrum and a Determination of Fractal Space Dimensionality

The possibility to constrain fractal space dimensionality from Astrophysics and other areas is briefly reviewed. Assuming such dimensionality to be $3 + ε$, a limit to $ε$ can be inferred from COBE satellite data. The available data for the cosmic microwave background radiation spectrum are fitted by a Planck's radiation distribution generalized to non integer space dimensionality. Our analysis shows that the shape of the CMBR spectrum, which does not depend on the absolute normalization, is correctly described from this distribution provided the absolute temperature is equal to 2.726 $\pm$ $0.003\times 10^{-2}$ K and $ε= - (0.957 \pm 0.006) \times 10^{-5}$. This value for $ε$ is shown to be consistent with what is found on a very different spatial scale based on a quantum field phenomenon. The $|ε|$ is interpreted as an upper limit for how much space dimensionality could have deviated from three. In other words, this is the maximum fluctuation space dimensionality should have experienced in a spatial and temporal scale compared to that of the decoupling era.

astro-ph↗
arXiv2008

Bohr's atomic model revisited

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies. Some consequences of this procedure are examined.

physics.hist-ph↗
arXiv1995

Higher twist corrections to Bjorken sum rule

Some higher twist corrections to the Bjorken sum rule are estimated in the framework of a quark-diquark model of the nucleon. The parameters of the model have been previously fixed by fitting the measured higher twist corrections to the unpolarized structure function $F_2(x, Q^2)$. The resulting corrections to the Bjorken sum rule turn out to be negligible.

hep-ph↗