Abstract

Zoom link: https://maths-cam-ac-uk.zoom.us/j/94018037756

Active Brownian motion with intermittent direction reversals are common in a class of bacteria like Myxococcus Xanthus and Pseudomonas putida. We show that, for such a motion in two dimensions, the presence of the two time scales set by the rotational diffusion constant D_R and the reversal rate gamma give rise to four distinct dynamical regimes showing distinct behaviors. We analytically compute the position distribution which shows a crossover from a strongly non-diffusive and anisotropic behavior at short-times to a diffusive isotropic behavior via an intermediate regime. We find that the marginal distribution in the intermediate regime shows an exponential or Gaussian behavior depending on whether gamma is larger or smaller than D_R. We also find the persistence exponents in the four regimes. In particular, we show that a novel persistence exponent α = 1 emerges due to the direction reversal.