带源与汇的粒子系统
Particle systems with sources and sinks
AI总结:
本文通过带原点源的对称排斥过程与独立随机游走模型,揭示保守粒子系统中局部扰动的非局部效应,并依据底层随机游走的常返或瞬态刻画极限分布与爆炸行为。
摘要:
在保守粒子系统中,局部扰动可能对平稳测度产生非局部影响。为捕捉这一现象,本文分析了两个玩具模型。我们研究可数位置集合 V 上的对称排斥过程,在给定点(称为原点)设置一个源,并从密度为 $ρ$ 的 Bernoulli 乘积测度开始。我们证明,当 V 上的底层随机游走具有常返性时,系统会演化至完全占据状态;而在瞬态情形下,我们得到一个极限分布,它不是乘积分布,并具有长程相关性。对于 V 上的独立随机游走者,我们从 Poisson 测度出发分析同一问题。通过与一个常微分方程组(ODE)交织,我们证明在之后所有时刻 t > 0,分布均为 Poisson 分布;并且当且仅当底层随机游走常返时,系统在 t → ∞ 的极限中“爆炸”。在瞬态情形下,极限密度是该随机游走 Green 函数的一个简单函数。
英文摘要:
Local perturbations in conservative particle systems can have a non-local influence on the stationary measure. To capture this phenomenon, we analyze in this paper two toy models. We study the symmetric exclusion process on a countable set of sites V with a source at a given point (called the origin), starting from a Bernoulli product measure with density $ρ$. We prove that when the underlying random walk on V is recurrent, then the system evolves towards full occupation, whereas in the transient case we obtain a limiting distribution which is not product and has long-range correlations. For independent random walkers on V , we analyze the same problem, starting from a Poissonian measure. Via intertwining with a system of ODE's, we prove that the distribution is Poissonian at all later times t \> 0, and that the system ''explodes'' in the limit t $\rightarrow$ $\infty$ if and only if the underlying random walk is recurrent. In the transient case, the limiting density is a simple function of the Green's function of the random walk.
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