The phenomenon of quantum tunneling is relevant in different areas of physics, from chemical reactions to nuclear fission and fusion below the Coulomb barrier. In most of the cases one has to deal with the tunneling of a complex object with internal degrees of freedom. In a one-dimensional model we investigate how an harmonically bound two-body system tunnels through an external gaussian barrie...

Phosphorene is a two-dimensional nanomaterial with a direct band-gap at the Brillouin zone center. In this paper, we present a recently derived effective-mass theory of the band structure in the presence of strain and electric field, based upon group theory. Band parameters for this theory are computed using a first-principles theory based upon the generalized-gradient approximation to the dens...

A relativistic bounce-averaged quasilinear diffusion equation is derived to describe stochastic particle transport associated with arbitrary-frequency electromagnetic fluctuations in a nonuniform magnetized plasma. Expressions for the elements of a relativistic quasilinear diffusion tensor are calculated explicitly for magnetically-trapped particle distributions in axisymmetric magnetic geometr...

Martin Bojowald, 2, ∗ Hugo A. Morales-Técotl, 4, † and Hanno Sahlmann ‡ Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Am Mühlenberg 1, D-14476 Golm, Germany Center for Gravitational Physics and Geometry, The Pennsylvania State University, 104 Davey Lab, University Park, PA 16802, USA Departamento de F́ısica, Universidad Autónoma Metropolitana Iztapalapa, A.P. 55-534 Méxic...

The spin Hamiltonian parameters for the two Cu centers A1 and A2 in the calcined catalysts CuO–ZnO are theoretically investigated using the high order perturbation formulas of these parameters for a 3d ion in tetragonally elongated octahedra. In the above formulas, the tetragonal field parameters Ds and Dt are determined from the superposition model, by considering the relative axial elongation...

We study degree n polynomial perturbations of quadratic reversible Hamiltonian vector fields with one center and one saddle point. It was recently proved that if the first Poincaré–Pontryagin integral is not identically zero, then the exact upper bound for the number of limit cycles on the finite plane is n− 1. In the present paper we prove that if the first Poincaré–Pontryagin function is iden...

We use a superspin Hamiltonian defined on an infinite-dimensional Fock space with positive definite scalar product to study localization and delocalization of noninteracting spinless quasiparticles in quasione-dimensional quantum wires perturbed by weak quenched disorder. Past works using this approach have considered a single chain. Here, we extend the formalism to treat a quasi-one-dimensiona...

where ρ is the mass density, S is the entropy density, and p is the pressure. It was shown in Morrison and Greene [1980] that this system, as well as its magnetohydrodynamic extension, admit a noncanonical Poisson formulation, that is, equation (1.1) can be written as ḟ = {f, h}, relative to a Hamiltonian function h. The study of the relativistic case was initiated in Bia lynicki-Birula, Hubbar...