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arXiv 1606.04844cond-mat.stat-mech
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非奇异核定义的分数阶导数捕捉反常弛豫和扩散

Fractional derivative defined by non-singular kernels to capture anomalous relaxation and diffusion

HongGuang Sun, Xiaoxiao Hao, Yong Zhang, Dumitru Baleanu

摘要:

反常弛豫和扩散过程已经被广泛地表征为分数阶导数模型,其中分数阶导数的定义由于奇异记忆核而挑战数值计算,因此仍然是历史上的争论。本研究首先探讨松弛和扩散模型的物理性质,其中分数阶导数最近使用指数核定义。分析表明,分数阶导数模型与指数核不能表征非指数动力学以及记录在反常松弛和扩散。一个合法的扩展以前的分数阶导数,然后提出用拉伸指数核取代指数核。数值试验表明,拉伸指数核分数导数模型比指数核模型能更好地描述更宽范围的反常扩散过程,这意味着新分数导数模型在量化真实世界的反常弛豫和扩散过程中具有潜在的应用价值.

英文摘要:

Anomalous relaxation and diffusion processes have been widely characterized by fractional derivative models, where the definition of the fractional-order derivative remains a historical debate due to the singular memory kernel that challenges numerical calculations. This study first explores physical properties of relaxation and diffusion models where the fractional derivative was defined recently using an exponential kernel. Analytical analysis shows that the fractional derivative model with an exponential kernel cannot characterize non-exponential dynamics well-documented in anomalous relaxation and diffusion. A legitimate extension of the previous fractional derivative is then proposed by replacing the exponential kernel with a stretched exponential kernel. Numerical tests show that the fractional derivative model with the stretched exponential kernel can describe a much wider range of anomalous diffusion than the exponential kernel, implying the potential applicability of the new fractional derivative in quantifying real-world, anomalous relaxation and diffusion processes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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