title: Crossing probability for directed polymers in random media. II. Exact tail of the distribution.
abstract: We study the probability p ≡ p(η)(t) that two directed polymers in a given random potential η and with fixed and nearby endpoints do not cross until time t. This probability is itself a random variable (over samples η), which, as we show, acquires a very broad probability distribution at large time. In particular, the moments of p are found to be dominated by atypical samples where p is of order unity. Building on a formula established by us in a previous work using nested Bethe ansatz and Macdonald process methods, we obtain analytically the leading large time behavior of all moments p(m) ≃ γ(m)/t. From this, we extract the exact tail ∼ρ(p)/t of the probability distribution of the noncrossing probability at large time. The exact formula is compared to numerical simulations, with excellent agreement.
authors.affiliation: LPTMS, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.
authors.forename: Andrea
authors.initials: A
authors.lastname: De Luca
authors.affiliation: Laboratoire de Physique Théorique de l'ENS, CNRS and Ecole Normale Supérieure de Paris, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Le Doussal