On the scaling properties of (2+1) directed polymers in the high temperature limit

Abstract

In this paper in terms of the replica method we consider the high temperature limit of (2+1) directed polymers in a random potential and propose an approach which allows to compute the scaling exponent $θ$ of the free energy fluctuations as well as the left tail of its probability distribution function. It is argued that $θ= 1/2$ which is different from the zero-temperature numerical value which is close to 0.241. This result implies that unlike the $(1+1)$ system in the two-dimensional case the free energy scaling exponent is non-universal being temperature dependent.