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Accueil du site > Séminaires > Séminaires 2021 > MSC Visio-Seminar. September 21st 2021. Ada Altieri (MSC, Université de Paris) : "Evidence of glassy phases in large well-mixed ecosystems with competitive and cooperative interactions".

MSC Visio-Seminar. September 21st 2021. Ada Altieri (MSC, Université de Paris) : "Evidence of glassy phases in large well-mixed ecosystems with competitive and cooperative interactions"

Sauf mention contraire, les séminaires et les soutenances se déroulent à 11h30 en salle 454A du bâtiment Condorcet.


There will be a live diffusion with Zoom.

Tuesday September 21st, 11h30 (exceptional schedule)

Contact Michael Berhanu to attend the video seminar

Evidence of glassy phases in large well-mixed ecosystems with competitive and cooperative interactions

Pr. Ada Altieri

Laboratoire Matière et Systèmes Complexes (MSC), Université de Paris

Abstract : Cases in which the number of interacting components is very large are becoming of general interest in disparate fields, such as in ecology and biology, e.g. for bacteria communities, and economy where many agents trade and interact simultaneously both in financial markets and in complex economic systems. Many of these systems appear often to be poised at the edge of stability, hence displaying enormous responses to external perturbations. This feature, also known in physics as marginal stability, is usually related to the complex underlying interaction network, which can induce critical behaviors.

In this talk, I will present the problem of ecological complexity by focusing on a reference model in theoretical ecology, the disordered Lotka-Volterra model with random symmetric interactions and finite demographic noise. Employing advanced statistical physics techniques, I will unveil a complex and rich structure for the organization of the equilibria in a central model for ecological communities. Notably, I will relate emergent collective behaviors and slow relaxation dynamics, as supported by numerical simulations, to the appearance of disordered phases akin to those occurring in glassy systems.

Finally, I will discuss the extension of these results to non-logistic growth functions in the dynamics of the species abundances, which turn out to be beneficial to model intra-specific mutualistic effects.

References :

A. Altieri, F. Roy, C. Cammarota, G. Biroli, Phys. Rev. Lett. 126, 258301 (2021) ;

A. Altieri, G. Biroli, arXiv:2105.04519 (2021), to appear in SciPost Physics.


Contact : Équipe séminaires / Seminar team - Published on / Publié le 30 août


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