12 citations · 52 across the 10 of their papers we have counts for
12 papers
A Constructive Approach to a Class of Overdetermined Problems
Alessandro Fortunati, Filomena Pacella
In this paper we study an overdetermined problem which is directly related to the well known torsion problem studied by J. Serrin. A perturbed version of the latter is tackled by u…
Analytical solutions for ultra-fast precessional switching in inertial magnetization dynamics
Alessandro Fortunati, Massimiliano d'Aquino, Claudio Serpico
Here we consider the magnetization dynamics in ferromagnetic nanoparticles or films driven by external magnetic field pulses directed transverse to the initial equilibrium state. T…
Controlled Quasi-Latitudinal Solutions for ultra-fast Spin-Torque Precessional Magnetization Switching
Alessandro Fortunati, Massimiliano d'Aquino, Claudio Serpico
The aim of the paper is to present a novel class of time-dependent controls to realize ultra-fast magnetization switching in nanomagnets driven by spin-torques produced by spin-pol…
On the constructivity of the variational approach to Arnold's Diffusion
Alessandro Fortunati
The aim of this paper is to discuss the constructivity of the method originally introduced by U. Bessi to approach the phenomenon of topological instability commonly known as Arnol…
Travelling waves over an arbitrary bathymetry: a perturbation theory approach
Alessandro Fortunati
The problem of a travelling wave over an arbitrary quasi-flat bathymetry in a semi infinite channel is studied in the shallow-water formulation. It is shown how the streamfunction…
Integrability and strong normal forms for non-autonomous systems in a neighbourhood of an equilibrium
Alessandro Fortunati, Stephen Wiggins
The paper deals with the problem of existence of a convergent "strong" normal form in the neighbourhood of an equilibrium, for a finite dimensional system of differential equations…
Negligibility of small divisor effects in the normal form theory for nearly-integrable Hamiltonians with decaying non-autonomous perturbations
Alessandro Fortunati, Stephen Wiggins
The paper deals with the problem of the existence of a normal form for a nearly-integrable real-analytic Hamiltonian with aperiodically time-dependent perturbation decaying (slowly…
Normal forms à la Moser for aperiodically time-dependent Hamiltonians in the vicinity of a hyperbolic equilibrium
Alessandro Fortunati, Stephen Wiggins
The classical theorem of Moser, on the existence of a normal form in the neighbourhood of a hyperbolic equilibrium, is extended to a class of real-analytic Hamiltonians with aperio…
A Kolmogorov theorem for nearly-integrable Poisson systems with asymptotically decaying time-dependent perturbation
Alessandro Fortunati, Stephen Wiggins
The aim of this paper is to prove the Kolmogorov theorem of persistence of Diophantine flows for nearly-integrable Poisson systems associated to a real analytic Hamiltonian with ap…
Persistence of Diophantine flows for quadratic nearly-integrable Hamiltonians under slowly decaying aperiodic time dependence
Alessandro Fortunati, Stephen Wiggins
The aim of this paper is to prove a Kolmogorov-type result for a nearly-integrable Hamiltonian, quadratic in the actions, with an aperiodic time dependence. The existence of a toru…
Normal Form and Nekhoroshev stability for nearly-integrable Hamiltonian systems with unconditionally slow aperiodic time dependence
Alessandro Fortunati, Stephen Wiggins
The aim of this paper is to extend the results of Giorgilli and Zehnder for aperiodic time dependent systems to a case of general nearly-integrable convex analytic Hamiltonians. Th…
Fast drift and diffusion in an example of isochronous system through Windows Method
Alessandro Fortunati
We study the problem of Arnold's diffusion in an example of isochronous system by using a geometrical method known as Windows Method. Despite the simple features of this example, w…