Universal Survival Probability for a d-Dimensional Run-and-Tumble Particle.
Physical review letters 124:9 (2020) 090603
Abstract:
We consider an active run-and-tumble particle (RTP) in d dimensions and compute exactly the probability S(t) that the x component of the position of the RTP does not change sign up to time t. When the tumblings occur at a constant rate, we show that S(t) is independent of d for any finite time t (and not just for large t), as a consequence of the celebrated Sparre Andersen theorem for discrete-time random walks in one dimension. Moreover, we show that this universal result holds for a much wider class of RTP models in which the speed v of the particle after each tumbling is random, drawn from an arbitrary probability distribution. We further demonstrate, as a consequence, the universality of the record statistics in the RTP problem.Time Between the Maximum and the Minimum of a Stochastic Process.
Physical review letters 123:20 (2019) 200201