Spin Waves without Spin Waves: A Case for Soliton Propagation in Starling Flocks

Physical Review Letters 2026 Open access

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Authors: Andrea Cavagna, Guido Cimino, Javier Cristín, Matteo Fiorini, Irene Giardina, Angelo Giustiniani, Tomás S. Grigera, Stefania Melillo, Roberto A. Palombella, Leonardo Parisi, Antonio Ponno, Mattia Scandolo
+1 more Zachary S. Stamler
DOI: 10.1103/sppm-qsnb
Cited by: 1
References: 46

Abstract

Collective turns in starling flocks propagate linearly with negligible attenuation, indicating the existence of an underdamped sector in the dispersion relation. According to linear response theory, beside granting linear propagation of the phase perturbations, the real part of the frequency should also yield a spin-wave form of the unperturbed correlation function. However, new high-resolution experiments on real flocks show that underdamped traveling waves coexist with an overdamped Lorentzian correlation. Theory and experiments are reconciled once we add to the dynamics a Fermi-Pasta-Ulam-Tsingou term.

Fields of Study & Subjects

Nonlinear Dynamics and Pattern Formation Nonlinear Photonic Systems Spectroscopy and Quantum Chemical Studies

Publication details

Journal / source
Physical Review Letters
Publisher
American Physical Society (APS)
Volume
137
Issue
9
Pages
098301–098301
Publication date
27 August 2026
Language
EN