Radice Mattia, Cristadoro Giampaolo
<a href="https://ror.org/01bf9rw71">Max Planck Institute for the Physics of Complex Systems</a>, 01187 Dresden, Germany.
Dipartimento di Matematica e Applicazioni, <a href="https://ror.org/01ynf4891">Università degli Studi Milano-Bicocca</a>, 20126 Milan, Italy.
Phys Rev E. 2024 Aug;110(2):L022103. doi: 10.1103/PhysRevE.110.L022103.
We consider a one-dimensional search process under stochastic resetting conditions. A target is located at b≥0 and a searcher, starting from the origin, performs a discrete-time random walk with independent jumps drawn from a heavy-tailed distribution. Before each jump, there is a given probability r of restarting the walk from the initial position. The efficiency of a "myopic search"-in which the search stops upon crossing the target for the first time-is usually characterized in terms of the first-passage time τ. On the other hand, great relevance is encapsulated by the leapover length l=x_{τ}-b, which measures how far from the target the search ends. For symmetric heavy-tailed jump distributions, in the absence of resetting the average leapover is always infinite. Here we show instead that resetting induces a finite average leapover ℓ_{b}(r) if the mean jump length is finite. We compute exactly ℓ_{b}(r) and determine the condition under which resetting allows for nontrivial optimization, i.e., for the existence of r^{} such that ℓ_{b}(r^{}) is minimal and smaller than the average leapover of the single jump.
我们考虑在随机重置条件下的一维搜索过程。目标位于(b\geq0)处,搜索者从原点出发,进行离散时间随机游走,其独立跳跃服从重尾分布。在每次跳跃之前,有给定的概率(r)从初始位置重新开始游走。“近视搜索”(即首次越过目标时搜索停止)的效率通常用首次通过时间(\tau)来表征。另一方面,跨越长度(l = x_{\tau}-b)具有重要意义,它衡量搜索结束时距离目标有多远。对于对称重尾跳跃分布,在没有重置的情况下,平均跨越总是无穷大。相反,我们在此表明,如果平均跳跃长度有限,重置会导致有限的平均跨越(\ell_{b}(r))。我们精确计算(\ell_{b}(r)),并确定重置允许进行非平凡优化的条件,即存在(r^{})使得(\ell_{b}(r^{}))最小且小于单次跳跃的平均跨越。