Non-relativistic classical mechanics for spinning particles

We study the classical dynamics of non-relativistic particles endowed with spin. Non-vanishing Zitterbewegung terms appear in the equation of motion also in the small momentum limit. We derive a generalized work-energy theorem which suggests classical interpretations for tunnel effect and quantum potential

Deriving Spin within a discrete-time theory

We prove that the classical theory with a discrete time (chronon) is a particular case of a more general theory in which spinning particles are associated with generalized Lagrangians containing time-derivatives of any order (a theory that has been called "Non-Newtonian Mechanics"). As a consequence, we get, for instance, a classical kinematical derivation of Hamiltonian and spin vector for the mentioned chronon theory (e.g., in Caldirola et al.'s formulation).Comment: 10 pages; LaTeX fil

Black hole dynamical evolution in a Lorentz-violating spacetime

We consider the black hole dynamical evolution in the framework of a Lorentz-violating spacetime endowed with a Schwarzchild-like momentum-dependent metric. Large deviations from the Hawking-Bekenstein predictions are obtained, depending on the values of the Lorentz-violating parameter lambda introduced. A non-trivial evolution comes out, following mainly from the existence of a non-vanishing minimum mass: for large Lorentz violations, most of the black hole evaporation takes place in the initial stage, which is then followed by a stationary stage (whose duration depends on the value of lambda) where the mass does not change appreciably. Furthermore, for the final stage of evolution, our model predicts a sweet slow death of the black hole, whose "slowness" again depends on lambda, in contrast with the violent final explosion predicted by the standard theory.Comment: 8 pages, 8 figure

Fundamental times, lengths and physical constants: some unknown contributions by Ettore Majorana

We review the introduction in physics of the concepts of an elementary space length and of a fundamental time scale, analyzing some related unknown contributions by Ettore Majorana. In particular, we discuss the quasi-Coulombian scattering in presence of a finite length scale, as well as the introduction of an intrinsic (universal) time delay in the expressions for the retarded electromagnetic potentials. Finally, we also review a special model considered by Majorana in order to deduce the value of the elementary charge, in such a way anticipating key ideas later introduced in quantum electrodynamics.Comment: 10 page

Helicity-0 spinning particles

We show that a self-consistent classical theory of the spin, based on a very general Lagrangian extending the Newtonian dynamics, does predict the special case of helicity-0 particles, which at the same time are endowed with nonzero spin and zero intrinsic angular momentum.Comment: 9 page

Generalized Ginzburg-Landau models for non-conventional superconductors

We review some recent extensions of the Ginzburg-Landau model able to describe several properties of non-conventional superconductors. In the first extension, s-wave superconductors endowed with two different critical temperatures are considered, their main thermodynamical and magnetic properties being calculated and discussed. Instead in the second extension we describe spin-triplet superconductivity (with a single critical temperature), studying in detail the main predicted physical properties. A thorough discussion of the peculiar predictions of our models and their physical consequences is as well performed.Comment: 16 pages, 2 figure