Search results for "matematica"
showing 10 items of 1637 documents
Cyclical generation of reconnected magnetic fields by electron pressure gra-dients
2021
The theoretical basis for the cyclical generation of macroscopic reconnected magnetic fields in low collisionality plasma regimes is formulated. The relevant process is sustained by the “thermal” energy of the electron population.In particular, an oscillatory mode propagating along and across a confining magnetic field is identified that involves the magnetic reconnection region where the ratio of the longitudinal to transverse electron thermal conductivity is relatively large. A periodic exchange of reconnected magnetic field conductivity energy with electron thermal energy is sustained within a region that remains significant even when the magnetic field configuration from which the mode …
Two positive solutions for a nonlinear parameter-depending algebraic system
2021
The existence of two positive solutions for a nonlinear parameter-depending algebraic system is investigated. The main tools are a finite dimensional version of a two critical point theorem and a recent weak-strong discrete maximum principle.
Two positive solutions for a nonlinear parameter-depending algebraic system
2021
The existence of two positive solutions for a nonlinear parameter-depending algebraic system is investigated. The main tools are a finite dimensional version of a two critical point theorem and a recent weak-strong discrete maximum principle.
Duality-invariant dispersion relations for electromagnetic and gravitational waves at Planck scales
2012
In this paper we explore some mathematical aspects of a duality-invariant Einstein-Planck relation on electromagnetic waves and gravitational waves at a Planckian scale. We explore a generalized version of Maxwell's equations leading to the proposed duality-invariant dispersion relation for electromagnetic waves. We also study the analogous aspects of duality in a post-Newtonian description of gravitational waves.
Normalized Solutions to the Fractional Schrödinger Equation with Potential
2023
AbstractThis paper is concerned with the existence of normalized solutions to a class of Schrödinger equations driven by a fractional operator with a parametric potential term. We obtain minimization of energy functional associated with that equations assuming basic conditions for the potential. Our work offers a partial extension of previous results to the non-local case.
The Vlasov limit and its fluctuations for a system of particles which interact by means of a wave field
2005
preprint math-ph/0506078
Hydrodynamic limits from multiphase Boltzmann models
2016
We shall describe the validation of hydrodynamic models for thin sprays from a class of multiphase Boltzmann models where the collision kernels share a common structure, and include elastic collisions and some kind of inelastic collisions
MR3535311 Reviewed Inoue, H.(J-KYUSGM); Takakura, M.(J-FUE-AM) Regular biorthogonal pairs and pseudo-bosonic operators. (English summary) J. Math. Ph…
2017
Given a pair of operators a and b acting on a Hilbert space H, such that [a,b]=1, the authors give a method to construct a regular bi-orthogonal pair of sequences in H. They study the relationship between the conditions on a,b,a†,b† and the operators Ae,Be,A†e,B†e, considered by one of the authors in a previous paper, in the set-up of a general theory of bi-orthogonal pair sequences. Then they give a method to construct operators A and B with the so-called D-pseudo bosons conditions, i.e. the commutation rule and some assumptions, on a dense subspace D of H, considered in the literature. Finally, some physical examples are given.
More mathematics on pseudo-bosons
2013
We propose an alternative definition for pseudo-bosons. This simplifies the mathematical structure, minimizing the required assumptions. Some physical examples are discussed, as well as some mathematical results related to the biorthogonal sets arising out of our framework. We also briefly extend the results to the so-called nonlinear pseudo-bosons.
Pseudo-bosons, so far
2011
In the past years several extensions of the canonical commutation relations have been proposed by different people in different contexts and some interesting physics and mathematics have been deduced. Here, we review some recent results on the so-called pseudo-bosons. They arise from a special deformation of the canonical commutation relation [a,a †]= ll, which is replaced by [a,b]=ll, with b not necessarily equal to a †. We start discussing some of their mathematical properties and then we discuss several examples.