Archive ouverte HAL – A first-order dynamical transition in the displacement distribution of a driven run-and-tumble particle

Giacomo Gradenigo 1 Satya N. Majumdar 2 Satya Majumdar 2

Giacomo Gradenigo, Satya N. Majumdar, Satya Majumdar. A first-order dynamical transition in the displacement distribution of a driven run-and-tumble particle. Journal of Statistical Mechanics: Theory and Experiment, IOP Publishing, 2019, 2019 (5), pp.053206. ⟨10.1088/1742-5468/ab11be⟩. ⟨hal-02291859⟩

We study the probability distribution $P(X_N=X,N)$ of the total displacement $X_N$ of an $N$-step run and tumble particle on a line, in presence of a constant nonzero drive $E$. While the central limit theorem predicts a standard Gaussian form for $P(X,N)$ near its peak, we show that for large positive and negative $X$, the distribution exhibits anomalous large deviation forms. For large positive $X$, the associated rate function is nonanalytic at a critical value of the scaled distance from the peak where its first derivative is discontinuous. This signals a first-order dynamical phase transition from a homogeneous `fluid' phase to a `condensed' phase that is dominated by a single large run. A similar first-order transition occurs for negative large fluctuations as well. Numerical simulations are in excellent agreement with our analytical predictions.

  • 1. LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]
  • 2. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques