Random Initial Data and Average Shock Time in the Fermi-Pasta-Ulam-Tsingou Chain
Abstract
We investigate the dynamics of the Fermi-Pasta-Ulam-Tsingou chain with long-wavelength random initial data. When the energy per particle is small, thermal equilibrium is not reached on a fast timescale, and the system enters prethermalization. The formation of the prethermal state is characterized by the development of a Burgers-type shock and the onset of a turbulentlike spectrum with a time dependent exponent ζ(t) in the inertial range. We perform a significant step forward by demonstrating that these features are robust under generic long-wavelength random initial conditions. By employing advanced probabilistic techniques inspired by the works of Dudley and Talagrand, we derive a sharp asymptotic expression for the average shock time in the thermodynamic limit. For large p, this time scales as (psqrt[logp])^{-1}, where p is the number of excited modes, proving that it is an intensive quantity up to a logarithmic correction in the size of the system.
Related
- Recent progress on thermal transport in one-dimensional long-range interacting Fermi-Pasta-Ulam-Tsingou lattice systems
- Heat transport in weakly anharmonic Fermi-Pasta-Ulam-Tsingou chains
- Heat Transport of the β-Fermi--Pasta--Ulam--Tsingou chain in the long-wave limit
- Continuum Dirac Theory and Nonlinear Extensions of a Chain of Alternating non-linear springs: an SSH version of the Fermi-Pasta-Ulam-Tsingou model
- Gap-controlled thermalization in a chain of alternating nonlinear springs: an SSH model version of the Fermi-Pasta-Ulam-Tsingou problem
BibTeX
@article{gallone2026random,
title = {{Random Initial Data and Average Shock Time in the Fermi-Pasta-Ulam-Tsingou Chain}},
author = {Matteo Gallone and Ricardo Grande and Antonio Ponno and Stefano Ruffo and Erwan Druais},
journal = {Physical Review Letters},
year = {2026},
month = may,
doi = {10.1103/qxzs-1t1l},
eprint = {2511.07664},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05773710v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Random Initial Data and Average Shock Time in the Fermi-Pasta-Ulam-Tsingou Chain
AU - Matteo Gallone
AU - Ricardo Grande
AU - Antonio Ponno
AU - Stefano Ruffo
AU - Erwan Druais
PY - 2026
DA - 2026/05/27
JO - Physical Review Letters
DO - 10.1103/qxzs-1t1l
UR - https://hal.science/hal-05773710v1
AB - We investigate the dynamics of the Fermi-Pasta-Ulam-Tsingou chain with long-wavelength random initial data. When the energy per particle is small, thermal equilibrium is not reached on a fast timescale, and the system enters prethermalization. The formation of the prethermal state is characterized by the development of a Burgers-type shock and the onset of a turbulentlike spectrum with a time dependent exponent ζ(t) in the inertial range. We perform a significant step forward by demonstrating that these features are robust under generic long-wavelength random initial conditions. By employing advanced probabilistic techniques inspired by the works of Dudley and Talagrand, we derive a sharp asymptotic expression for the average shock time in the thermodynamic limit. For large p, this time scales as (psqrt[logp])^{-1}, where p is the number of excited modes, proving that it is an intensive quantity up to a logarithmic correction in the size of the system.
SN - 0031-9007
SN - 1079-7114
ER -