Lima, F. N. Lima, R. P. A. Lyra, M. L.
Published in
Brazilian Journal of Physics

Using a first-order time-dependent perturbation theory, we calculate the spontaneous emission rate of a two-level system trapped between perfectly reflecting concentric spheres. The emitter is represented by a two-level monopole coupled to a Hermitian massless scalar field satisfying Dirichlet boundary conditions in such quantum-confined low-dimens...

da Silva, Lucilene Moraes Pimenta, Amilcar Porto
Published in
Brazilian Journal of Physics

This paper presents a computational analysis of the stability of the small Brazilian space capsule known as SARA (Atmospheric Reentry Satellite). SARA capsule was developed by the Institute of Aeronautics and Space (IAE) in cooperation with Brazilian Space Agency (AEB) to perform experiments in microgravity environment and return to the Earth. Thus...

Caruso, F. Oguri, V. Silveira, F.
Published in
Brazilian Journal of Physics

In this paper, a quantum dot mathematical model based on a two-dimensional Schrödinger equation assuming the 1/r inter-electronic potential is revisited. Generally, it is argued that the solutions of this model obtained by solving a biconfluent Heun equation have some limitations. The known polynomial solutions are confronted with new numerical cal...

Sattari, F. Aslanzadeh, M.
Published in
Brazilian Journal of Physics

The spectroscopy of light and strange baryons and elastic electromagnetic form factors of nucleon have been studied through a simple semi-relativistic quark model. For SU(6)-invariant part of spectrum, we treated the baryons as a spin-independent three-body bound system and presented the exact analytical solution of three-body Klein–Gordon equation...

Esmail, S. Salah, Ahmed Hassan, Samia S. A.
Published in
Brazilian Journal of Physics

In this work, the problem of the quantum optical model is considered where an one-mode quantized radiation field interacts with a two-level atom (TLA). Also, the atomic position distribution is taken into account, i.e., the atom passing through the length of the optical cavity. We believe that the atomic position affects the matter-field interactio...

Bergeron, Hervé Curado, Evaldo M. F. Gazeau, Jean-Pierre Rodrigues, Ligia M. C. S.
Published in
Brazilian Journal of Physics

The aim of the present article is to introduce and to discuss some of the most basic fundamental concepts of quantum physics by using orientations or angles in the plane, illustrated through linear polarizations. We start with the Euclidean plane, which is certainly a paradigmatic example of a Hilbert space. The orientations in the plane are identi...

Khan, Shahab Ullah Adnan, Muhammad Mahmood, Shahzad Ur-Rehman, Hafeez Qamar, Anisa
Published in
Brazilian Journal of Physics

The propagation properties of electrostatic cnoidal waves (periodic waves) and solitons are studied in a magnetized electron-positron-ion (EPI) plasma bearing ion pressure anisotropy and superthermality. In a two-dimensional geometry, we considered the ions to be warm having pressure anisotropy due to magnetic field. The anisotropic ions are modele...

Reddy, B. Joji Vickraman, P. Justin, A. Simon
Published in
Brazilian Journal of Physics

An attempt has been made in preparing graphene composite matrix with Ni(OH)2 in a green route via Moringa oleifera plant leaf extract in an ordinary co-precipitation method for supercapacitor applications. The as-prepared graphene and its composites with various molar ratios of Ni(OH)2 are investigated by XRD, UV, Raman, XPS, SEM, and TEM analyses ...

Manjunatha, H. C. Sridhar, K. N.
Published in
Brazilian Journal of Physics

We have studied the Ti-induced fusion reactions for the synthesis of superheavy elements with atomic number in the range 104 ≤ Z ≤ 130 for all projectile target combinations. We have obtained a semi-empirical formula for fusion barrier heights (VB), positions (RB), curvatures of the inverted parabola (ħω) of Ti-induced fusion reactions for the synt...

Garcia, P. R. A. F. Loza, K. Daumann, S. Grasmik, V. Pappert, K. Rostek, A. Helmlinger, J. Prymak, O. Heggen, M. Epple, M.
...
Published in
Brazilian Journal of Physics

The combination of simultaneous measurements of small and wide angle X-ray scattering (SAXS/WAXS–SWAXS) to investigate the overall size, shape, and crystallinity of silver nanoparticles and alloyed silver-gold nanoparticles in the size range of 8 to 80 nm is shown. The obtained results for overall size are in agreement with the particle size obtain...