Free Energy of the Cauchy Directed Polymer Model at High Temperature

Abstract

We study the Cauchy directed polymer model on ${\mathbb{Z}}^{1+1}$, where the underlying random walk is in the domain of attraction to the $1$-stable law. We show that, if the random walk satisfies certain regularity assumptions and its symmetrized version is recurrent, then the free energy is strictly negative at any inverse temperature $\beta >0$. Moreover, under additional regularity assumptions on the random walk, we can identify the sharp asymptotics of the free energy in the high temperature limit, namely, \begin{equation*} \lim\limits_{β\to0}β^{2}\log(-p(β))=-c. \end{equation*}

References in corpus (2)

• Pinning on a defect line: characterization of marginal disorder relevance and sharp asymptotics for the critical point shift
• On the Long-range Directed Polymer Model