论文标题
动荡环境和随机噪声对自组织的临界行为的影响:普遍性与非大学性
Effects of Turbulent Environment and Random Noise on Self-Organized Critical Behavior: Universality vs Nonuniversality
论文作者
论文摘要
在“跑步sandpile”的HWA-KARDAR模型中进行自组织的临界性[Phys。 Rev. A 45,7002(1992)]通过使用现场理论重新归一化组(RG)来研究环境的湍流运动。动荡的流程是由Avellaneda和Majda [Commun引入的合成$ D $二维各向异性速度合奏建模的。数学。 Phys.131:381(1990)]有有限的相关时间。具有时间独立的(空间淬灭)随机噪声的HWA-KARDAR模型与原始模型一起使用白噪声。本文的目的是探索RG方程的固定点,这些方程确定了通用类别的可能类型(系统的关键行为制度)和可测量数量的关键维度。我们的计算表明,随机噪声类型的影响非常大:与系统具有三个固定点的白噪声相比,空间淬火噪声的情况涉及四个固定点具有重叠的稳定性区域。这意味着,在后一种情况下,系统的关键行为不仅取决于系统的全局参数,这是通常的情况,而且还取决于系统的电荷(耦合常数)的初始值。这些初始条件决定了RG流将达到的特定固定点。由于现在,系统的关键属性并未严格由其参数来定义,因此情况可能被解释为违反普遍性。这样的系统并非禁止,但它们非常罕见。特别有趣的是,没有环境动荡动作的同一模型不能预测这种非杂物行为,并证明了具有规定的普遍性类别的“常见” [J.〜STAT。物理。 178,392(2020)]。
Self-organized criticality in the Hwa-Kardar model of "running sandpile" [Phys. Rev. A 45, 7002 (1992)] with a turbulent motion of the environment taken into account is studied with the field theoretic renormalization group (RG). The turbulent flow is modelled by the synthetic $d$-dimensional anisotropic velocity ensemble introduced by Avellaneda and Majda [Commun. Math. Phys.131: 381 (1990)] with finite correlation time. The Hwa-Kardar model with time-independent (spatially quenched) random noise is considered alongside the original model with the white noise. The aim of the present paper is to explore fixed points of RG equations which determine the possible types of universality classes (regimes of critical behavior of the system) and critical dimensions of the measurable quantities. Our calculations demonstrate that influence of the type of the random noise is extremely large: in contrast to the case of the white noise where the system possess three fixed points, the case of the spatially quenched noise involves four fixed points with overlapping stability regions. This means that in the latter case the critical behavior of the system depends not only on the global parameters of the system which is the usual case, but also on the initial values of the charges (coupling constants) of the system. These initial conditions determine the specific fixed point which will be reached by RG flow. Since now the critical properties of the system are not defined strictly by its parameters the situation may be interpreted as universality violation. Such systems are not forbidden but they are very rare. It is especially interesting that the same model without turbulent motion of the environment does not predict this nonuniversal behavior and demonstrates the "usual" one with prescribed universality classes instead [J.~Stat. Phys. 178, 392 (2020)].