arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2409.01337cond-mat.stat-mechmath-phmath.MPmath.PR
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边界驱动零范围过程在图上的电流波动:微观与宏观方法及非可逆电阻网络理论

Current fluctuations for the boundary-driven zero-range process on graphs: microscopic versus macroscopic approach and a theory of non-reversible resistor-like networks

Davide Gabrielli, Rosemary J. Harris

AI总结:

本文通过变分方法推导了图上电流的率泛函,揭示了微观与宏观视角的联系,并提出了一种非可逆电阻网络的简化方法。

摘要:

我们计算了在有限图上,一个由边界驱动的随机粒子系统在零范围动力学下,随时间趋于无穷大时,通过边的电流的联合大偏离率泛函。这一结果扩展了一维之前通过不同方法获得的结果;我们的替代技术揭示了各种联系和互补视角。特别是,我们在这里采用变分方法,通过从二级大偏离率泛函收缩来推导率泛函。我们进行了精确的最小化,并最终得到一个涉及每条边成本函数叠加的变分问题。不同边的贡献并不独立,因为它们通过图上节点的势函数值相关联。图上的率泛函是连续率泛函的微观版本,该连续率泛函由宏观波动理论预测,我们确实展示了在标度极限下的收敛。如果我们通过割集将图分成两个连通区域,并只关心通过割集的电流,我们发现结果与仅由一个有效边组成的有效系统相同(在宏观层面如此,并预期对其他模型也是如此)。这种有效边的特性与图的“容量”相关,可以通过使用类似电气网络的简化方法获得;具体来说,我们处理并联、串联以及N星配置(简化为有效完全N图)。我们的简化过程直接与简化到迹过程相关,并且由于动力学通常不可逆,它也与非可逆电气网络理论密切相关。

英文摘要:

We compute the joint large deviation rate functional in the limit of large time for the current flowing through the edges of a finite graph on which a boundary-driven system of stochastic particles evolves with zero-range dynamics.This generalizes one-dimensional results previously obtained with different approaches; our alternative techniques illuminate various connections and complementary perspectives. In particular, we here use a variational approach to derive the rate functional by contraction from a level 2.5 large deviation rate functional. We perform an exact minimization and finally obtain the rate functional as a variational problem involving a superposition of cost functions for each edge. The contributions from different edges are not independent since they are related by the values of a potential function on the nodes of the graph. The rate functional on the graph is a microscopic version of the continuous rate functional predicted by the macroscopic fluctuation theory, and we indeed show a convergence in the scaling limit. If we split the graph into two connected regions by a cutset and are interested just in the current flowing through the cutset, we find that the result is the same as that of an effective system composed of only one effective edge (as happens at macroscopic level and is expected also for other models). The characteristics of this effective edge are related to the ``capacities'' of the graph and can be obtained by a reduction using elementary transformations as in electrical networks; specifically, we treat components in parallel, in series, and in $N$-star configurations (reduced to effective complete $N$-graphs). Our reduction procedure is directly related to the reduction to the trace process and, since the dynamics is in general not reversible, it is also closely connected to the theory of non-reversible electrical networks.

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