Secondment to the Sorbonne University


Gabriel Morgado participated in the secondment at the “Statistical physics and modelization for chemistry, geochemistry, and biology” research division. The secondment was devoted to the work on the final paper and the writing of the thesis. The paper was published in the peer-reviewed journal Physical Chemistry Chemical Physics with the title “Elimination of fast variables in stochastic nonlinear kinetics.” The dissertation manuscript has been written. Its title is “Organization and fluctuations in living systems.” It is divided into four parts. The first part is devoted to the definition and contextualization of the methods employed in the papers. The second part is devoted to the steady-state approximation in small systems where the fluctuations of concentrations cannot be neglected and where nonlinearities are present. The next part is devoted to Turing patterns: scaling of submicrometric Turing patterns in growing systems and termination of Turing patterns in small chemical systems. The final part is devoted to the Fisher-Kolmogorov-Petrovsky-Piskunov front. Researchers show that differences in the diffusion coefficient in the autocatalytic reaction A + B -> 2A lead to shifts in the height and the width of the concentration profiles. The shifts can then be used to measure the perturbation of diffusion in concentrated systems. An important result is highlighted in the last section. It is shown that the presence of a cutoff at the leading edge of the front affects the speed in a nonintuitive way. This new result on a more-than-80 years old problem is an important feature of the manuscript.


1 Sep. 2020.- 1 Mar. 2021


Sorbonne Université, Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), France


Gabriel Morgado

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 711859.