论文标题
反应扩散PDE如何近似随机粒子模型的大型人群限制
How reaction-diffusion PDEs approximate the large-population limit of stochastic particle models
论文作者
论文摘要
反应扩散PDE和基于粒子的随机反应扩散(PBSRD)模型是建模化学和生物系统空间动力学的常用方法。标准反应扩散PDE模型忽略了空间传输和反应的潜在随机性,并且通常在系统中有大量粒子的方案中被描述为适当的。最近的研究证明了PBSRD模型的严格大型人口限制,显示了所得的平均场模型(MFM)对应于局部 - 脑差分方程的非本地系统。在这项工作中,我们探讨了标准反应扩散PDE模型与派生的MFM之间的严格关系。我们证明,前者可以解释为对后期的渐近近似,即双分子反应核是短距离且平均的。随着反应性相互作用长度尺度接近零,我们证明MFMS以二阶收敛到标准反应 - 扩散PDE模型。在证明这一结果时,我们还可以在通用系统的时间内建立MFM模型的本地良好性,并为特定的反应系统和内核建立了全球范围的良好性。最后,我们说明了几个数值示例的MFM,SM和基础粒子模型之间的一致性和分歧。
Reaction-diffusion PDEs and particle-based stochastic reaction-diffusion (PBSRD) models are commonly-used approaches for modeling the spatial dynamics of chemical and biological systems. Standard reaction-diffusion PDE models ignore the underlying stochasticity of spatial transport and reactions, and are often described as appropriate in regimes where there are large numbers of particles in a system. Recent studies have proven the rigorous large-population limit of PBSRD models, showing the resulting mean-field models (MFM) correspond to non-local systems of partial-integro differential equations. In this work we explore the rigorous relationship between standard reaction-diffusion PDE models and the derived MFM. We prove that the former can be interpreted as an asymptotic approximation to the later in the limit that bimolecular reaction kernels are short-range and averaging. As the reactive interaction length scale approaches zero, we prove the MFMs converge at second order to standard reaction-diffusion PDE models. In proving this result we also establish local well-posedness of the MFM model in time for general systems, and global well-posedness for specific reaction systems and kernels. Finally, we illustrate the agreement and disagreement between the MFM, SM and the underlying particle model for several numerical examples.