Challenger Joseph D, Burioni Raffaella, Fanelli Duccio
Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, United Kingdom.
Dipartimento di Fisica e Astronomia, Università di Firenze, INFN and CSDC, Via Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Aug;92(2):022818. doi: 10.1103/PhysRevE.92.022818. Epub 2015 Aug 26.
The Turing instability is a paradigmatic route to pattern formation in reaction-diffusion systems. Following a diffusion-driven instability, homogeneous fixed points can become unstable when subject to external perturbation. As a consequence, the system evolves towards a stationary, nonhomogeneous attractor. Stable patterns can be also obtained via oscillation quenching of an initially synchronous state of diffusively coupled oscillators. In the literature this is known as the oscillation death phenomenon. Here, we show that oscillation death is nothing but a Turing instability for the first return map of the system in its synchronous periodic state. In particular, we obtain a set of approximated closed conditions for identifying the domain in the parameter space that yields the instability. This is a natural generalization of the original Turing relations, to the case where the homogeneous solution of the examined system is a periodic function of time. The obtained framework applies to systems embedded in continuum space, as well as those defined on a networklike support. The predictive ability of the theory is tested numerically, using different reaction schemes.
图灵不稳定性是反应扩散系统中模式形成的一种典型途径。在扩散驱动的不稳定性之后,均匀不动点在受到外部扰动时会变得不稳定。因此,系统会朝着一个稳定的、非均匀吸引子演化。稳定模式也可以通过对扩散耦合振荡器的初始同步状态进行振荡猝灭来获得。在文献中,这被称为振荡死亡现象。在这里,我们表明振荡死亡只不过是系统在其同步周期状态下首次返回映射的图灵不稳定性。特别是,我们得到了一组近似的封闭条件,用于确定参数空间中产生不稳定性的区域。这是原始图灵关系的自然推广,适用于所研究系统的均匀解是时间周期函数的情况。所得到的框架适用于嵌入连续空间的系统,以及定义在类似网络支撑上的系统。使用不同的反应方案对该理论的预测能力进行了数值测试。