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Bibliographic Details
Main Authors: Neill, Duff, Liu, Hanqing
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.08925
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author Neill, Duff
Liu, Hanqing
author_facet Neill, Duff
Liu, Hanqing
contents Spin-models, where the $N$ spins interact pairwise with a $SU(n_f)$ symmetry preserving hamiltonian, famously simplify in the large $n_f$, $N$ limits, as derived by Sachdev and Ye when exploring mean-field behavior of spin-glasses. We present numerical evidence that for a large class of models, the large $n_f$ limit is not necessary: the same dynamical equations can describe the relaxation processes at high temperatures for a set of classical models inspired from mean-field treatments of interacting dense neutrino gases, up to times set by the radius of convergence of the perturbation series for the correlation function. After a simple rescaling of time, the dynamics display a surprising universality, being identical for any value of $n_f$ as long as the rank of the coupling matrix is small. As a corollary of our results, we find that the direct interaction approximation originating from the study of stochastic flows in fluid turbulence should be thought of as only a short-time approximation for generic random coupling systems.
format Preprint
id arxiv_https___arxiv_org_abs_2504_08925
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Universality of $SU(\infty)$ relaxation dynamics for $SU(n_f)$-symmetric spin-models
Neill, Duff
Liu, Hanqing
High Energy Physics - Theory
Disordered Systems and Neural Networks
Nuclear Theory
Fluid Dynamics
Spin-models, where the $N$ spins interact pairwise with a $SU(n_f)$ symmetry preserving hamiltonian, famously simplify in the large $n_f$, $N$ limits, as derived by Sachdev and Ye when exploring mean-field behavior of spin-glasses. We present numerical evidence that for a large class of models, the large $n_f$ limit is not necessary: the same dynamical equations can describe the relaxation processes at high temperatures for a set of classical models inspired from mean-field treatments of interacting dense neutrino gases, up to times set by the radius of convergence of the perturbation series for the correlation function. After a simple rescaling of time, the dynamics display a surprising universality, being identical for any value of $n_f$ as long as the rank of the coupling matrix is small. As a corollary of our results, we find that the direct interaction approximation originating from the study of stochastic flows in fluid turbulence should be thought of as only a short-time approximation for generic random coupling systems.
title Universality of $SU(\infty)$ relaxation dynamics for $SU(n_f)$-symmetric spin-models
topic High Energy Physics - Theory
Disordered Systems and Neural Networks
Nuclear Theory
Fluid Dynamics
url https://arxiv.org/abs/2504.08925