Length Scales in Brownian yet Non-Gaussian Dynamics Miotto, José M. Pigolotti, Simone Chechkin, Aleksei V. Roldán Vargas, Sándalo We thank Walter Kob for fruitful exchanges about this work and Lorenzo Rovigatti for his assistance with the tetrahedral system simulations. We also thank the anonymous reviewers for their careful reading of our manuscript and their insightful comments and suggestions. A. V. C. acknowledges partial financial support from the Deutsche Forschungsgemeinschaft (DFG Grant No. ME 1535/7-1). S. R.-V. acknowledges support from the European Commission through the Marie Sklodowska-Curie Individual Fellowship No. 840195-ARIADNE. According to the classical theory of Brownian motion, the mean-squared displacement of diffusing particles evolves linearly with time, whereas the distribution of their displacements is Gaussian. However, recent experiments on mesoscopic particle systems have discovered Brownian yet non-Gaussian regimes where diffusion coexists with an exponential tail in the distribution of displacements. Here we show that, contrary to the present theoretical understanding, the length scale λ associated with this exponential distribution does not necessarily scale in a diffusive way. Simulations of Lennard-Jones systems reveal a behavior λ ∼ t1=3 in three dimensions and λ ∼ t1=2 in two dimensions. We propose a scaling theory based on the idea of hopping motion to explain this result. In contrast, simulations of a tetrahedral gelling system, where particles interact by a nonisotropic potential, yield a temperature-dependent scaling of λ. We interpret this behavior in terms of an intermittent hopping motion. Our findings link the Brownian yet non-Gaussian phenomenon with generic features of glassy dynamics and open new experimental perspectives on the class of molecular and supramolecular systems whose dynamics is ruled by rare events. 2021-07-26T10:11:01Z 2021-07-26T10:11:01Z 2021-07-02 info:eu-repo/semantics/article Miotto, J. M... [et al.] (2021). Length scales in Brownian yet non-Gaussian dynamics. Physical Review X, 11(3), 031002. DOI: [10.1103/PhysRevX.11.031002] http://hdl.handle.net/10481/69911 10.1103/PhysRevX.11.031002 eng info:eu-repo/grantAgreement/EC/H2020/840195 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España American Physical Society