论文标题
耦合种群的灭绝和非高斯噪声下的罕见事态动态
Extinctions of coupled populations, and rare-event dynamics under non-Gaussian noise
论文作者
论文摘要
自然种群的生存可能会受到空间和时间各不相同的环境条件的极大影响。我们查看一个居住在两个位置（补丁）的人口，并随着迁移的迁移而及时波动。我们报告了两个发现。首先，我们发现与许多其他系统中的罕见事件不同，在这里导致罕见灭绝事件的历史并非由单个路径主导。我们开发了适当的框架，事实证明这是标准的鞍点方法的混合体，而Donsker-varadhan形式主义将很长一段时间以来处理非典型平均值的罕见事件。它提供了导致罕见事件的历史统计数据的详细描述。该框架适用于由非高斯噪声驱动的广泛系统中的罕见事件。其次，将此框架应用于人群 - 动力学模型，我们发现其灭绝行为的新相变。令人惊讶的是，即使通常降低了人口的规模和增长率，也可以减少灭绝的可能性，但它是一个水槽（个人死亡比出生更多的地方）。
The survival of natural populations may be greatly affected by environmental conditions that vary in space and time. We look at a population residing in two locations (patches) coupled by migration, in which the local conditions fluctuate in time. We report on two findings. First, we find that unlike rare events in many other systems, here the histories leading to a rare extinction event are not dominated by a single path. We develop the appropriate framework, which turns out to be a hybrid of the standard saddle-point method, and the Donsker-Varadhan formalism which treats rare events of atypical averages over a long time. It provides a detailed description of the statistics of histories leading to the rare event. The framework applies to rare events in a broad class of systems driven by non-Gaussian noise. Secondly, applying this framework to the population-dynamics model, we find a novel phase transition in its extinction behavior. Strikingly, a patch which is a sink (where individuals die more than are born), can nonetheless reduce the probability of extinction, even if it normally lowers the population's size and growth rate.
