Starts 27 Apr 2023 14:30
Ends 27 Apr 2023 15:30
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CMSP Seminar (Joint ICTP/SISSA Statistical Physics): Complexity of large ecological communities through the lens of statistical physics
Hybrid Seminar
Room 128 (SISSA, via Bonomea) + Zoom
Ada Altieri
(Paris)
(Paris)
Abstract:
Many complex systems in Nature, from metabolic networks to ecosystems, appear to be poised at the edge of stability, hence displaying enormous responses to external perturbations. This marginal stability condition is often the consequence of the complex underlying interaction network, which can induce large-scale collective dynamics, and therefore critical behaviors.
In this talk, I will address some of the still open questions -- from the configurational landscape analysis to stability criteria up to the emergence of spatial disordered patterns -- by discussing the Generalized Lotka-Volterra model in the limit of many randomly interacting species and finite demographic noise. Leveraging on techniques rooted in the spin-glass and random matrix theory, I will unveil a very rich structure in the organization of the equilibria [1] and relate the slowing down of correlation functions to glassy-like features [1-2].
Finally, I will discuss possible generalizations to non-logistic growth behavior [3-4]. On the one hand, this will lead to astonishing stabilization mechanisms to be framed within the long-standing diversity-stability debate initiated by May. On the other hand, these developments will allow us to describe positive feedback mechanisms and eventually pinpoint new phase transitions as a smoking-gun signature of criticality.
References:
[1] A. Altieri, F. Roy, C. Cammarota, G. Biroli, Phys. Rev. Lett. 126, 258301 (2021);
[2] G. Garcia Lorenzana, A. Altieri, Phys. Rev. E 105 (2022);
[3] A. Altieri, G. Biroli, SciPost Physics 12, 013 (2022);
[4] I. Hatton, O. Mazzarisi, A. Altieri and M. Smerlak, submitted to Science (2023).
In this talk, I will address some of the still open questions -- from the configurational landscape analysis to stability criteria up to the emergence of spatial disordered patterns -- by discussing the Generalized Lotka-Volterra model in the limit of many randomly interacting species and finite demographic noise. Leveraging on techniques rooted in the spin-glass and random matrix theory, I will unveil a very rich structure in the organization of the equilibria [1] and relate the slowing down of correlation functions to glassy-like features [1-2].
Finally, I will discuss possible generalizations to non-logistic growth behavior [3-4]. On the one hand, this will lead to astonishing stabilization mechanisms to be framed within the long-standing diversity-stability debate initiated by May. On the other hand, these developments will allow us to describe positive feedback mechanisms and eventually pinpoint new phase transitions as a smoking-gun signature of criticality.
References:
[1] A. Altieri, F. Roy, C. Cammarota, G. Biroli, Phys. Rev. Lett. 126, 258301 (2021);
[2] G. Garcia Lorenzana, A. Altieri, Phys. Rev. E 105 (2022);
[3] A. Altieri, G. Biroli, SciPost Physics 12, 013 (2022);
[4] I. Hatton, O. Mazzarisi, A. Altieri and M. Smerlak, submitted to Science (2023).