arXiv subjects

Diego Rial

Publications and source records attributed to Diego Rial.

7 recordsLinked to original sources

arXiv2026

High-order time splitting methods for the nonlinear Gross-Pitaevskii equation

We propose a high-order numerical methodology for computing the ground state and time evolution of the two-dimensional Gross-Pitaevskii equation with harmonic trapping potential. The ground state is obtained by combining normalized gradient flow with time-splitting schemes featuring strictly positive coefficients, which makes them suitable for both dissipative and Hamiltonian regimes and avoids the negative time steps required by classical symplectic methods. The computational cost of these methods grows quadratically with the order, in contrast to the exponential growth of symplectic alternatives. Numerical benchmarks assess ground state convergence under different initializations, long-time preservation of mass and Hamiltonian energy for varying mass constraints, and the cost-accuracy trade-off for orders q = 2, 4,..., 14.

math.NA↗

arXiv2018

Existence of Peregrine Solitons in fractional reaction-diffusion equations

In this article, we will analyze the existence of Peregrine type solutions for the fractional diffusion reaction equation by applying Splitting-type methods. These functions that have two main characteristics, they are direct sum of functions of periodic type and functions that tend to zero at infinity. Global existence results are obtained for each particular characteristic, for then finally combining both results.

math.AP↗

arXiv2018

Global existence for vector valued fractional reaction-diffusion equations

In this paper, we study the initial value problem for infinite dimensional fractional non-autonomous reaction-diffusion equations. Applying general time-splitting methods, we prove the existence of solutions globally defined in time using convex sets as invariant regions. We expose examples, where biological and pattern formation systems, under suitable assumptions, achieve global existence. We also analyze the asymptotic behavior of solutions.

math.AP↗

arXiv2013

High order methods for irreversible equations

In this work, we show high order splitting methods of integration without negative steps, allowing us to solve numerically irreversible problems, like reaction-diffusion equations. The methods consist in a suitable affine combinations of Lie-Trotter schemes with different steps. We prove convergence of this methods for a large class of semi-linear problems, that includes Hamiltonian and reaction-diffusion systems.

math.NA↗

arXiv2012

Lie-Trotter method for abstract semilinear evolution equations

In this paper we present a unified picture concerning Lie-Trotter method for solving a large class of semilinear problems: nonlinear Schr\"odinger, Schr\"oginger--Poisson, Gross--Pitaevskii, etc. This picture includes more general schemes such as Strang and Ruth--Yoshida. The convergence result is presented in suitable Hilbert spaces related with the time regularity of the solution and is based on Lipschitz estimates for the nonlinearity. In addition, with extra requirements both on the regularity of the initial datum and on the nonlinearity we show the linear convergence of the method.

math.NA↗

arXiv2012

Controllability of Schroedinger equation with a nonlocal term

This paper is concerned with the internal distributed control problem for the 1D Schroedinger equation, $i\,u_t(x,t)=-u_{xx}+α(x)\,u+m(u)\,u,$ that arises in quantum semiconductor models. Here $m(u)$ is a non local Hartree--type nonlinearity stemming from the coupling with the 1D Poisson equation, and $α(x)$ is a regular function with linear growth at infinity, including constant electric fields. By means of both the Hilbert Uniqueness Method and the Schauder's fixed point theorem it is shown that for initial and target states belonging to a suitable small neighborhood of the origin, and for distributed controls supported outside of a fixed compact interval, the model equation is controllable. Moreover, it is shown that, for distributed controls with compact support, the exact controllability problem is not possible.

math-ph↗

arXiv2004

The influence of rotation in radiation driven winds from hot stars II. CAK topological analysis

The topological analysis from Bjorkman (1995) for the standard model that describes the winds from hot stars by Castor, Abbott & Klein (1975) has been extended to include the effect of stellar rotation and changes in the ionization of the wind. The differential equation for the momentum of the wind is non--linear and transcendental for the velocity gradient. Due to this non--linearity the number of solutions that this equation possess is not known. After a change of variables and the introduction of a new physically meaningless independent variable, we manage to replace the non--linear momentum differential equation by a system of differential equations where all the derivatives are {\it{explicitely}} given. We then use this system of equations to study the topology of the rotating--CAK model. For the particular case when the wind is frozen in ionization ($δ=0$) only one physical solution is found, the standard CAK solution, with a X--type singular point. For the more general case ($δ\neq 0$), besides the standard CAK singular point, we find a second singular point which is focal--type (or attractor). We find also, that the wind does not adopt the maximal mass--loss rate but almost the minimal.

astro-ph↗