arXiv subjects

Thomas Robiglio

Publications and source records attributed to Thomas Robiglio.

4 recordsLinked to original sources

arXiv2025

Multiscale patterns of migration flows in Austria: regionalization, administrative barriers, and urban-rural divides

Migration is central in various societal problems related to socioeconomic development. While much of the existing research has focused on international migration, migration patterns within a single country remain relatively unexplored. In this work we study internal migration patterns in Austria for a period of over 20 years, obtained from open and high-granularity administrative records. We employ inferential network methods to characterize the flows between municipalities and extract their clustering according to similar target and destination rates. Our methodology reveals significant deviations from commonly assumed relocation patterns modeled by the gravity law. At the same time, we observe unexpected biases of internal migrations that leads to less frequent movements across boundaries at both district and state levels than predictions suggest. This leads to significant regionalization of migration at multiple geographical scales and augmented division between urban and rural areas. These patterns appear to be remarkably persistent across decades of migration data, demonstrating systematic limitations of conventionally used gravity models in migration studies. Our approach presents a robust methodology that can be used to improve such evaluations, and can reveal new phenomena in migration networks.

physics.soc-ph↗

arXiv2024

Higher-order Ising model on hypergraphs

Non-dyadic higher-order interactions affect collective behavior in various networked dynamical systems. Here we discuss the properties of a novel Ising model with higher-order interactions and characterize its phase transitions between the ordered and the disordered phase. By a mean-field treatment, we show that the transition is continuous when only three-body interactions are considered but becomes abrupt when interactions of higher orders are introduced. Using a Georges-Yedidia expansion to go beyond a na\"ive mean-field approximation, we reveal a quantitative shift in the critical point of the phase transition, which does not affect the universality class of the model. Finally, we compare our results with traditional $p$-spin models with many-body interactions. Our work unveils new collective phenomena on complex interacting systems, revealing the importance of investigating higher-order systems beyond three-body interactions.

cond-mat.stat-mech↗

arXiv2024

Synergistic signatures of group mechanisms in higher-order systems

The interplay between causal mechanisms and emerging collective behaviors is a central aspect of understanding, controlling, and predicting complex networked systems. In our work, we investigate the relationship between higher-order mechanisms and higher-order behavioral observables in two representative models with group interactions: a simplicial Ising model and a social contagion model. In both systems, we find that group (higher-order) interactions show emergent synergistic (higher-order) behavior. The emergent synergy appears only at the group level and depends in a complex, non-linear way on the trade-off between the strengths of the low- and higher-order mechanisms and is invisible to low-order behavioral observables. Our work sets the basis for systematically investigating the relation between causal mechanisms and behavioral patterns in complex networked systems with group interactions, offering a robust methodological framework to tackle this challenging task.

physics.soc-ph↗

arXiv2022

Simplicially driven simple contagion

Single contagion processes are known to display a continuous transition from an epidemic-free phase at low contagion rates to the epidemic state for rates above a critical threshold. This transition can become discontinuous when two simple contagion processes are coupled in a bi-directional symmetric way. However, in many cases, the coupling is not symmetric and the processes can be of a different nature. For example, risky social behaviors -- such as not wearing masks or engaging in large gatherings -- can affect the spread of a disease, and their adoption dynamics via social reinforcement mechanisms are better described by complex contagion models, rather than by the simple contagion paradigm, which is more appropriate for disease spreading phenomena. Motivated by this example, we consider a simplicial contagion (describing the adoption of a behavior) that uni-directionally drives a simple contagion (describing a disease propagation). We show that, above a critical driving strength, such driven simple contagion can exhibit both discontinuous transitions and bi-stability, which are instead absent in standard simple contagions. We provide a mean-field analytical description of the phase diagram of the system, and complement the results with Markov-chain simulations. Our results provide a novel route for a simple contagion process to display the phenomenology of a higher-order contagion, through a driving mechanism that may be hidden or unobservable in many practical instances.

physics.soc-ph↗