2025-10-30 カリフォルニア大学サンディエゴ校(UCSD)
実験的な蠕動運動とモデリングデータの比較。(左)円は健常な腸で記録された振動周期で、灰色の階段はモデルから得られたものです。(右)振動の3つの時間経過の構造。
<関連情報>
- https://today.ucsd.edu/story/synchronized-frequencies-helps-you-digest-food
- https://journals.aps.org/prl/abstract/10.1103/8njd-qd14
不均一振動媒体における欠陥、区画化、および再正規化された負の拡散係数 Defects, Parcellation, and Renormalized Negative Diffusivities in Nonhomogeneous Oscillatory Media
Marie Sellier-Prono, Massimo Cencini, David Kleinfeld, and Massimo Vergassola
Physical Review Letters Published: 14 October, 2025
DOI: https://doi.org/10.1103/8njd-qd14
Abstract
Spatial nonhomogeneities can synchronize clusters of spatially extended oscillators in different frequency plateaus. Motivated by physiological rhythms, we fully characterize the phase diagram of a Ginzburg-Landau (GL) model with a gradient of frequencies. For large gradients and diffusion, the rest state is stable, and the linear spectrum around it maps onto the non-Hermitian Bloch-Torrey equation. When complex pairs of eigenvalues turn unstable, precursors of plateaus grow, separated by defects where the GL amplitude vanishes. Nonlinear effects either saturate the amplitude of plateaus or lead to a phase-locked state, with saddle-node bifurcations separating the two regimes. In the region of plateaus, we trace the formation of defects to a nonlinear renormalization of the diffusivity, and determine the scaling of their number and length vs dynamical parameters.
