A systematic study of hydrodynamic attractors in periodically driven systems at weak and strong couplings
Abstract
We study equilibration and hydrodynamic response in conformal systems undergoing periodic expansion and contraction along one spatial direction. Using strongly coupled holography (AdS/CFT), weakly coupled kinetic theories (relaxation-time approximation, scalar ϕ4 theory and the Yang--Mills sector of QCD effective kinetic theory) and hydrodynamics (Navier--Stokes, Müller--Israel--Stewart (MIS) and rBRSSS), we investigate the shear response to a periodic drive of varying amplitude A and frequency ω, both analytically in linear response and numerically. We find that, at the linear level, A≪ 1, periodically driven systems approach a cyclic attractor that in general differs from Navier--Stokes behaviour. This attractor is universal among kinetic theories and accurately described by MIS theory: for slow driving, ωτπ≪ 1, where τπ is the shear relaxation time, it approaches the Navier--Stokes limit, whereas for fast driving the shear stress saturates at its non-interacting (free-streaming) value. In strongly coupled holographic systems, the periodic drive excites non-hydrodynamic quasinormal modes, which produce a characteristic ringing in the approach to the cyclic attractor, in contrast to the purely exponential approach found in kinetic theories. This difference is a direct consequence of the distinct non-hydrodynamic spectra of the two classes of theories. Moreover, unlike in kinetic theory, the holographic response is sensitive to the curvature terms of second-order hydrodynamics. Over longer times, non-linear viscous heating, which is quadratic in the drive amplitude, raises the temperature and thereby lowers ωτπ, since τπ∼ 1/T. This induces a slow drift of the cyclic attractor, which eventually converges towards Navier--Stokes hydrodynamics at asymptotically late times.
Related
BibTeX
@misc{mazeliauskas2026systematic,
title = {{A systematic study of hydrodynamic attractors in periodically driven systems at weak and strong couplings}},
author = {Aleksas Mazeliauskas and Toshali Mitra and Sören Schlichting and Simon Schneider and Louis Nwakile Onwuka and Martin Vrdoljak},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40877},
eprint = {2610.40877},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40877},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A systematic study of hydrodynamic attractors in periodically driven systems at weak and strong couplings
AU - Aleksas Mazeliauskas
AU - Toshali Mitra
AU - Sören Schlichting
AU - Simon Schneider
AU - Louis Nwakile Onwuka
AU - Martin Vrdoljak
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40877
UR - https://arxiv.org/abs/2610.40877
AB - We study equilibration and hydrodynamic response in conformal systems undergoing periodic expansion and contraction along one spatial direction. Using strongly coupled holography (AdS/CFT), weakly coupled kinetic theories (relaxation-time approximation, scalar ϕ^4 theory and the Yang--Mills sector of QCD effective kinetic theory) and hydrodynamics (Navier--Stokes, Müller--Israel--Stewart (MIS) and rBRSSS), we investigate the shear response to a periodic drive of varying amplitude A and frequency ω, both analytically in linear response and numerically. We find that, at the linear level, A≪ 1, periodically driven systems approach a cyclic attractor that in general differs from Navier--Stokes behaviour. This attractor is universal among kinetic theories and accurately described by MIS theory: for slow driving, ωτ_π≪ 1, where τ_π is the shear relaxation time, it approaches the Navier--Stokes limit, whereas for fast driving the shear stress saturates at its non-interacting (free-streaming) value. In strongly coupled holographic systems, the periodic drive excites non-hydrodynamic quasinormal modes, which produce a characteristic ringing in the approach to the cyclic attractor, in contrast to the purely exponential approach found in kinetic theories. This difference is a direct consequence of the distinct non-hydrodynamic spectra of the two classes of theories. Moreover, unlike in kinetic theory, the holographic response is sensitive to the curvature terms of second-order hydrodynamics. Over longer times, non-linear viscous heating, which is quadratic in the drive amplitude, raises the temperature and thereby lowers ωτ_π, since τ_π∼ 1/T. This induces a slow drift of the cyclic attractor, which eventually converges towards Navier--Stokes hydrodynamics at asymptotically late times.
ER -