有限系统中旋节线分解期间早期谱选择的方向记忆
Directional memory of early spectral selection during spinodal decomposition in finite systems
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中文总结 AI 辅助
本研究通过二维Cahn-Hilliard模拟发现，旋节线分解早期傅里叶谱选择的方向与后期粗化方向相关，且利用早期各向异性信息可小幅提升后期状态预测精度。
中文摘要 AI 辅助
Cahn-Hilliard相分离将小的成分涨落转变为粗化畴。在傅里叶空间中，图案形成一个环，其角向强度偏向某一轴。我们探究演化早期所偏好的轴是否与同一演化后期所偏好的轴保持关联。我们分析了具有各向同性初始涨落且无外加方向的二维模拟。我们引入$Q_2$，即傅里叶谱上的归一化角向平均，作为谱各向异性强度和方向的度量。线性增长以不同速率放大不同波数，从初始谱的角向不平衡中选出早期轴。该轴在粗化过程中与后期轴保持相关。在固定时刻，浅淬火显示出更强的早期-后期对齐。当在不同淬火于畴生长的相似阶段进行比较时，这一优势消失。将早期$Q_2$添加到基于淬火深度、平均组成和盒子尺寸的预测中，可将后期$Q_2$的平均绝对误差降低$3.53\%$。当仅保留早期$Q_2$的幅度，或将其方向替换为另一次演化中的方向时，这一降低消失。因此，早期傅里叶强度携带着关于同一演化场后期状态的信息。
英文摘要
Cahn-Hilliard phase separation turns small composition fluctuations into coarsening domains. In Fourier space, the pattern forms a ring whose angular intensity favors an axis. We ask whether the axis favored early in an evolution remains related to the axis favored later in the same evolution. We analyze two-dimensional simulations with isotropic initial fluctuations and no imposed direction. We introduce $Q_2$, a normalized angular average over the Fourier spectrum, as a measure of the strength and direction of spectral anisotropy. Linear growth amplifies different wave numbers at different rates, selecting an early axis from the angular imbalances in the initial spectrum. This axis remains correlated with the late axis during coarsening. At a fixed time, shallow quenches show stronger early-late alignment. This advantage disappears when the quenches are compared at similar stages of domain growth. Adding the early $Q_2$ to a prediction based on quench depth, mean composition, and box size reduces the mean absolute error for late $Q_2$ by $3.53\%$. This reduction disappears when only the magnitude of the early $Q_2$ is retained, or when its direction is replaced by the direction from another evolution. The early Fourier intensity therefore carries information about the later state of the same evolving field.
发表机构
- School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）
- Department of Physics, School of Science, Lanzhou University of Technology（兰州理工大学理学院物理系）
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