Alejandro J. Alvarez-Socorro

Digital Transformation with GCP Badge

alvarez.ciencia@gmail.com — Sat, 17 Sep 2022 18:50:23 +0000

I will retake the posting on this blog recommending the course:

Introduction to Digital Transformation with Google Cloud. https://googlecourses.qwiklabs.com/course_templates/266

It is an interest course with focus on understand the value offer of the public cloud services and how to take advantage of it in the path to the digital transformation.

Paper: Transition from nonradiative to radiative oscillons in parametrically driven systems

alvarez.ciencia@gmail.com — Mon, 18 May 2020 01:35:09 +0000

Nonequilibrium systems exhibit particle-type solutions. Oscillons are one of the best-known localized states of systems with time-dependent forcing or parametrically driven systems. We investigate the transition from nonradiative to radiative oscillons in the parametrically driven sine-Gordon model in two spatial dimensions. The bifurcation takes place when the strength of the forcing (frequency) increases (decreases) above a certain threshold. As a result of this transition, the oscillon emits radially symmetric evanescent waves. Numerically, we provide the phase diagram and show the supercritical nature of this transition. For small oscillations, based on the amplitude equation approach, the sine-Gordon equation with time-dependent forcing is transformed into the parametrically driven damped nonlinear Schrödinger model in two spatial dimensions. This amplitude equation exhibits a transition between nonradiative to radiative localized structures, consistently. Both models show quite good agreement.

This papers is available at: https://journals.aps.org/pre/abstract/10.1103/PhysRevE.101.052209

End of 2019 at Zenta

alvarez.ciencia@gmail.com — Mon, 11 May 2020 06:03:27 +0000

Webinar: Zenta Dashboard for monitor and predict infections of COVID-19 at Chile

alvarez.ciencia@gmail.com — Mon, 11 May 2020 05:57:14 +0000

A webinar about the COVID, technological tools for monitor COVID-19, and mathematical models for predicts its propagation.

Paper: Chaotic motion of localized structures

alvarez.ciencia@gmail.com — Sun, 10 May 2020 20:20:08 +0000

Mobility properties of spatially localized structures arising from chaotic but deterministic forcing of the bistable Swift-Hohenberg equation are studied and compared with the corresponding results when the chaotic forcing is replaced by white noise. Short structures are shown to possess greater mobility, resulting in larger root-mean-square speeds but shorter displacements than longer structures. Averaged over realizations, the displacement of the structure is ballistic at short times but diffusive at larger times. Similar results hold in two spatial dimensions. The effects of chaotic forcing on the stability of these structures are also quantified. Shorter structures are found to be more fragile than longer ones, and their stability region can be displaced outside the pinning region for constant forcing. Outside the stability region, the deterministic fluctuations lead either to the destruction of the structure or to its gradual growth.

Figure. (left panel) Chaotic Motion of localized structure and (right panel) its centroidal dynamics.

The paper is available at: https://journals.aps.org/pre/abstract/10.1103/PhysRevE.101.042212

Paper: Front depinning by deterministic and stochastic fluctuations: A comparison

alvarez.ciencia@gmail.com — Fri, 19 Jul 2019 19:27:37 +0000

Driven dissipative many-body systems are described by differential equations for macroscopic variables which include fluctuations that account for ignored microscopic variables. Here, we investigate the effect of deterministic fluctuations, drawn from a system in a state of phase turbulence, on front dynamics. We show that despite these fluctuations a front may remain pinned, in contrast to fronts in systems with Gaussian white noise fluctuations, and explore the pinning-depinning transition. In the deterministic case, this transition is found to be robust but its location in parameter space is complex, generating a fractal-like structure. We describe this transition by deriving an equation for the front position, which takes the form of an overdamped system with a ratchet potential and chaotic forcing; this equation can, in turn, be transformed into a linear parametrically driven oscillator with a chaotically oscillating frequency. The resulting description provides an unambiguous characterization of the pinning-depinning transition in parameter space. A similar calculation for noise-driven front propagation shows that the pinning-depinning transition is washed out.

The papers is avaliable at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.99.062226

Paper: Front propagation transition induced by diffraction in a liquid crystal light valve

alvarez.ciencia@gmail.com — Wed, 08 May 2019 12:34:11 +0000

Driven optical systems can exhibit coexistence of equilibrium states. Traveling waves or fronts between different states present complex spatiotemporal dynamics. We investigate the mechanisms that govern the front spread. Based on a liquid crystal light valve experiment with optical feedback, we show that the front propagation does not pursue minimization of free energy. Depending on the free propagation length in the optical feedback loop, the front speed exhibits a supercritical transition. Theoretically, from first principles, we use a model that takes it into account, characterizing the speed transition from a plateau to a growing regime. The theoretical and experimental results show quite fair agreement.

(a) Experimental Setup. (b) Propagative fronts in the LCLV.

The paper is avaliable at: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-27-9-12391&id=409101

Internship at the University of A Coruña

alvarez.ciencia@gmail.com — Wed, 08 May 2019 12:24:30 +0000

I realize a second internship at the Universidad de A Coruña in Spain, under the direction of the professors Susana Ladra and Oscar Pedreira, focused on the design and implementation of algorithms for data processing/mining. During my stay here I start a research project, that maybe will be finished soon.

In addition, I appear in a video of the BIRDS project

The university is beautiful as can be seen in the following photo:

I was delighted with this internship.

My internship at the Université Libre de Bruxelles (ULB)

alvarez.ciencia@gmail.com — Mon, 24 Sep 2018 09:20:18 +0000

In the first months of this year, I realize an internship in the Physics department at the Université Libre de Bruxelles (ULB). This was a fantastic experience for me as a Ph.D. student, thanks to the professor Mustapha Tlidi and my advisor Marcel Clerc, I get a lot of experience in my field (nonlinear physics / robust phenomena) and I have the opportunity to assist to the Solvay Workshop “Dynamics of biological systems: Modelling genetic, signaling and microbial networks”.

An unforgettable experience for me.

In addition, I enjoy the winter a lot.

Talk about Community Structures in Graphs at the University of A Coruña

alvarez.ciencia@gmail.com — Sun, 03 Jun 2018 21:39:02 +0000

As a part of my internship in the University of A Coruña, I realized a talk about community structures in graphs.