arXiv subjects

Reinaldo de Melo e Souza

Publications and source records attributed to Reinaldo de Melo e Souza.

22 records · Page 2Linked to original sources

arXiv2012

Image method in the calculation of the van der Waals force between an atom and a conducting surface

Initially, we make a detailed historical survey of van der Waals forces, collecting the main references on the subject. Then, we review a method recently proposed by Eberlein and Zietal to compute the dispersion van der Waals interaction between a neutral but polarizable atom and a perfectly conducting surface of arbitrary shape. This method has the advantage of relating the quantum problem to a corresponding classical one in electrostatics so that all one needs is to compute an appropriate Green function. We show how the image method of electrostatics can be conveniently used together with the Eberlein and Zietal mehtod (when the problem admits an image solution). We then illustrate this method in a couple of simple but important cases, including the atom-sphere system. Particularly, in our last example, we present an original result, namely, the van der Waals force between an atom and a boss hat made of a grounded conducting material.

quant-ph↗

arXiv2012

Sommerfeld's image method in the calculation of van der Waals forces

We show how the image method can be used together with a recent method developed by C. Eberlein and R. Zietal to obtain the dispersive van der Waals interaction between an atom and a perfectly conducting surface of arbitrary shape. We discuss in detail the case of an atom and a semi- infinite conducting plane. In order to employ the above procedure to this problem it is necessary to use the ingenious image method introduced by Sommerfeld more than one century ago, which is a generalization of the standard procedure. Finally, we briefly discuss other interesting situations that can also be treated by the joint use of Sommerfeld's image technique and Eberlein-Zietal method.

hep-th↗

arXiv2011

Finite size effects and non-additivity in the van der Waals interaction

We obtain analytically the exact non-retarded dispersive interaction energy between an atom and a perfectly conducting disc. We consider the atom in the symmetry axis of the disc and assume the atom is predominantly polarizable in the direction of this axis. For this situation we discuss the finite size effects on the corresponding interaction energy. We follow the recent procedure introduced by Eberlein and Zietal together with the old and powerful Sommerfeld's image method for non-trivial geometries. For the sake of clarity we present a detailed discussion of Sommerfeld's image method. Comparing our results form the atom-disc system with those recently obtained for an atom near a conducting plane with a circular aperture, we discus the non-additivity of the van der Waals interactions involving an atom and two complementary surfaces. We show that there is a given ratio z/a between the distance z from the atom to the center of the disc (aperture) and the radius of the disc a (aperture) for which non-additivity effects vanish. Qualitative arguments suggest that this quite unexpected result will occur not only for a circular hole, but for anyother symmetric hole.

hep-th↗

arXiv2009

Magnetic influence on classical dispersion

We discuss the Lorentz model for dispersion and absorption of radiation in dilute, linear and isotropic materials. Initially, with the purpose of making the paper as self-contained as possible, we reproduce the usual calculations concerning the interaction between the charged material oscillators and the electric field of the incident radiation, obtaining the main behavior of the reactive and dissipative electromagnetic properties of the materials. Thereafter, we also include the magnetic contribution of the Lorentz force to the equation of motion of the oscillators up to first order in $v/c$, which leads to some interesting results, like the approximately linear dependence of the refraction index with the radiation intensity and the appearance of a second region of anomalous dispersion around half the natural frequencies of the material.

physics.class-ph↗