Weak and strong turbulence in self-focusing and defocusing media

Fuente: arXiv
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Main Authors: Rosenhaus, Vladimir, Falkovich, Gregory
Format: Preprint
Published: 2025
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author Rosenhaus, Vladimir
Falkovich, Gregory
author_facet Rosenhaus, Vladimir
Falkovich, Gregory
contents While the focusing and defocusing Nonlinear Schrodinger Equations have similar behavior in the weak turbulence regime, they must differ dramatically in the strong turbulence regime. Here, we show that this difference is already present at next-to-leading order in the nonlinearity in the weak turbulence regime: The one-loop correction to the interaction vertex suppresses repulsion (like screening in electrodynamics), leading to a steeper spectrum in the defocusing case. In contrast, attraction enhancement (like antiscreening in chromodynamics) makes the spectrum less steep in the focusing case. To describe strong turbulence, we consider a vector model in the limit of a large number of components. A large-N kinetic equation, valid at all scales, can be derived analytically. It has an inverse-cascade solution whose two asymptotics, at high and low wavenumbers, describe weak and strong turbulence, respectively. We find two forms of universality in the strong turbulence spectrum: in focusing media it is independent of the flux magnitude, while in defocusing media it is independent of the bare coupling constant, with the largest scale appearing instead.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12451
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Weak and strong turbulence in self-focusing and defocusing media
Rosenhaus, Vladimir
Falkovich, Gregory
Fluid Dynamics
Quantum Gases
High Energy Physics - Theory
Chaotic Dynamics
While the focusing and defocusing Nonlinear Schrodinger Equations have similar behavior in the weak turbulence regime, they must differ dramatically in the strong turbulence regime. Here, we show that this difference is already present at next-to-leading order in the nonlinearity in the weak turbulence regime: The one-loop correction to the interaction vertex suppresses repulsion (like screening in electrodynamics), leading to a steeper spectrum in the defocusing case. In contrast, attraction enhancement (like antiscreening in chromodynamics) makes the spectrum less steep in the focusing case. To describe strong turbulence, we consider a vector model in the limit of a large number of components. A large-N kinetic equation, valid at all scales, can be derived analytically. It has an inverse-cascade solution whose two asymptotics, at high and low wavenumbers, describe weak and strong turbulence, respectively. We find two forms of universality in the strong turbulence spectrum: in focusing media it is independent of the flux magnitude, while in defocusing media it is independent of the bare coupling constant, with the largest scale appearing instead.
title Weak and strong turbulence in self-focusing and defocusing media
topic Fluid Dynamics
Quantum Gases
High Energy Physics - Theory
Chaotic Dynamics
url https://arxiv.org/abs/2501.12451