Year: 2026
Type: article
Abstract: This review provides an up-to-date account of energy transport in Fermi-Pasta-Ulam-Tsingou (FPUT) chains, a key testbed for nonequilibrium statistical physics. We discuss the transition from the historical puzzle of thermalization to the discovery of anomalous heat transport, where the effective thermal conductivity $$\kappa $$ κ diverges with system size L as $$\kappa \propto L^\delta $$ κ ∝ L δ . The article clarifies the distinction between two universality classes: the FPUT- $$\alpha \beta $$ α β model, characterized by $$\delta = 1/3$$ δ = 1 / 3 and linked to Kardar-Parisi-Zhang (KPZ) physics, and the symmetric FPUT- $$\beta $$ β model, where numerical and theoretical evidence support $$\delta = 2/5$$ δ = 2 / 5 . We investigate how finite-size effects—unavoidably induced by the thermostatting protocols— can disguise the asymptotic scaling. Additionally, we analyze the role of conservative noise in preserving hydrodynamic properties and examine how proximity to integrable limits leads to long-lived quasi-particles and, thereby, to diffusive regimes over intermediate spatial scales.
Source: Journal of Statistical Physics
Authors: Stefano Lepri, Roberto Livi, Antonio Politi
Language: English
Subfield: Statistical and Nonlinear Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,090
Award: G2630584159
OpenAlex ID: W7130360672
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