arXiv subjects

I. Bonamassa

Publications and source records attributed to I. Bonamassa.

3 recordsLinked to original sources

arXiv2024

Hybrid spinodals for long-range cascades

Cascades are self-reinforcing processes underlying the systemic risk of many complex systems. Understanding the universal aspects of these phenomena is of fundamental interest, yet typically bound to numerical observations in ad-hoc models and limited insights. Here, we develop a unifying approach and show that cascades induced by a long-range propagation of local perturbations are characterized by two universality classes determined by the parity invariance of the underlying process. We provide hyperscaling arguments predicting hybrid critical exponents given by a combination of both mean-field spinodal exponents and $d$-dimensional corrections and we show how global symmetries influence the geometry and lifetime of avalanches. Simulations encompassing classic and novel cascade models validate our predictions, revealing fundamental principles of cascade phenomena amenable to experimental validation.

cond-mat.dis-nn↗

arXiv2024

Logarithmic kinetics and bundling in physical networks

We explore the impact of volume exclusion on the local assembly of linear physical networks, where nodes and links are hard-core rigid objects. To do so, we introduce a minimal 3D model that helps us zoom into confined regions of these networks whose distant parts are sequentially connected by links with a very large aspect ratio. We show that the kinetics of link adhesion is logarithmic, as opposed to the algebraic growth in lower dimensions, and we attribute this qualitatively different behavior to a spontaneous delay of depletion forces caused by the 3D nature of the problem. Equally important, we find that this slow kinetics is metastable, allowing us to analytically predict an algebraic growth due to the formation of local bundles. Our findings offer a benchmark to study the local assembly of physical networks, with implications for non-equilibrium nest-like packings.

cond-mat.dis-nn↗

arXiv2022

Interdependent Superconducting Networks

Cascades are self-amplifying processes triggered by feedback mechanisms that may cause a substantial part of a macroscopic system to change its phase in response of a relatively small local event. The theoretical background for these phenomena is rich and interdisciplinary with interdependent networks providing a versatile "two-interactions" framework to study their multiscale evolution. Yet, physics experiments aimed at validating this ever-growing volume of predictions have remained elusive, hitherto hindered by the problem of identifying possible physical mechanisms realizing interdependent couplings. Here we develop and study the first experimental realization of an interdependent system as a multilayer network of two disordered superconductors separated by an insulating film. We show that Joule heating effects emerging at sufficiently large driving currents act as dependency links between the superconducting layers, igniting overheating cascades via adaptive back and forth electro-thermal feedbacks. Through theory and experiments, we unveil a rich phase diagram of mutual resistive transitions and cascading processes that physically realize and generalize interdependent percolation. The present work establishes the first physics laboratory bench for the manifestation of the theory of interdependent systems, enabling experimental studies to control and to further develop the multilayer phenomena of complex interdependent materials.

cond-mat.dis-nn↗