12,173 research outputs found
Fermi, Majorana and the statistical model of atoms
We give an account of the appearance and first developments of the
statistical model of atoms proposed by Thomas and Fermi, focusing on the main
results achieved by Fermi and his group in Rome. Particular attention is
addressed to the unknown contribution to this subject by Majorana, anticipating
some important results reached later by leading physicists.Comment: Latex, 16 pages, 2 figure
The Thomas-Fermi and the Thomas-Fermi-Dirac Models in Two-Dimension- the Effect of Strong Quantizing Magnetic Field
Using Thomas-Fermi (TF) and Thomas-Fermi-Dirac (TFD) models, we have
investigated the properties of electron gas inside two-dimensional (2D)
Wigner-Seitz (WS) cells in presence of a strong orthogonal quantizing magnetic
field. The electron-electron Coulomb exchange interaction in quasi-2D case is
obtained. The exact form of exchange term in 2D is derived making the width of
the system tending to zero. Further, using the exchange term, the
Thomas-Fermi-Dirac equation in 2D is established. It has been observed that
only the ionized WS cell can have finite radius in the Thomas-Fermi model, even
in presence of a strong quantizing magnetic field. On the other hand, in the
Thomas-Fermi-Dirac model a neutral WS cell can have finite radius.Comment: 9 pages LATEX file with two .eps figures (included), some version
will appear in EPJ D 71:5 (2017), DOI: 10.1140/epjd/e2016-70295-
Electrostatic potential in a superconductor
The electrostatic potential in a superconductor is studied. To this end
Bardeen's extension of the Ginzburg-Landau theory to low temperatures is used
to derive three Ginzburg-Landau equations - the Maxwell equation for the vector
potential, the Schroedinger equation for the wave function and the Poisson
equation for the electrostatic potential. The electrostatic and the
thermodynamic potential compensate each other to a great extent resulting into
an effective potential acting on the superconducting condensate. For the
Abrikosov vortex lattice in Niobium, numerical solutions are presented and the
different contributions to the electrostatic potential and the related charge
distribution are discussed.Comment: 19 pages, 11 figure
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