Spin Waves without Spin Waves: A Case for Soliton Propagation in Starling Flocks
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.
Authors
- Javier Cristín (ORCID: https://orcid.org/0000-0003-2091-0346)
- Antonio Ponno (ORCID: https://orcid.org/0000-0002-2869-189X)
- Tomás S. Grigera (ORCID: https://orcid.org/0000-0002-3165-4838)
- Stefania Melillo (ORCID: https://orcid.org/0000-0002-3459-7445)
- Andrea Cavagna (ORCID: https://orcid.org/0000-0003-2057-5971)
- Leonardo Parisi (ORCID: https://orcid.org/0000-0001-6425-5887)
- Mattia Scandolo (ORCID: https://orcid.org/0000-0001-6064-0382)
- Irene Giardina (ORCID: https://orcid.org/0000-0001-6900-1739)
- Zachary S. Stamler
- Guido Cimino
- Angelo Giustiniani
- Roberto A. Palombella
Institutions
- Universitat Autònoma de Barcelona (ES)
- University of Padua (IT)
- Istituto Nazionale di Fisica Nucleare (IT)
- University of Chicago (US)
- Instituto de Fisica de Liquidos y Sistemas Biologicos (AR)
- Centro Científico Tecnológico - La Plata (AR)
- Institute for Complex Systems (IT)
- Sapienza University of Rome (IT)
- Universidad Nacional de La Plata (AR)
Publication Details
- Journal
- Physical Review Letters
- Published
- 2026-08-27
- DOI
- https://doi.org/10.1103/sppm-qsnb
- Primary Topic
- Nonlinear Dynamics and Pattern Formation
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Ministero dell’Istruzione, dell’Università e della Ricerca
- European Research Council