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  • Open Access

Unifying renormalized and bare viscosity in two-dimensional molecular dynamics simulations

Kazuma Yokota*, Masato Itami, and Shin-ichi Sasa

  • *Contact author: yokota.kazuma.i26@kyoto-u.jp
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Phys. Rev. Research 8, 013234 – Published 3 March, 2026

DOI: https://doi.org/10.1103/58g1-c78g

Abstract

Fluctuating hydrodynamics provides a framework connecting mesoscopic fluctuations with macroscopic transport behavior. To bridge mesoscopic and macroscopic transport from microscopic dynamics, we introduce a wave-number-dependent viscosity, defined via the equilibrium correlation of time-averaged Fourier components of the fine-grained shear stress field. Two-dimensional molecular dynamics simulations reveal its small-wave-number divergence characteristic of the renormalized viscosity, while its large-wave-number behavior determines the bare viscosity, thereby establishing a link between mesoscopic and macroscopic transport based on microscopic dynamics.

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Phys. Rev. Research 8, 013234– Published 3 March, 2026
  • Received 19 June 2025
  • Accepted 30 January 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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