Asymptotics of the partition function for beta-ensembles at high temperature

Abstract: We consider a model for a gas of $N$ confined particles interacting via a two-body logarithmic interaction, namely the real $\beta$-ensembles. We are interested in the regime where the inverse temperature scales as $N\beta=2P$ with $P$ a fixed positive parameter; this is called the high-temperature regime. The confining potential is of the form $x^2+\phi$ with bounded smooth function $\phi$. We establish for this model, the existence of a large-$N$ asymptotic expansion for the associated partition function. We also prove the existence of a large-$N$ asymptotic expansion of linear statistics for general confining potentials. Our method is based on the analysis of the loop equations. Finally, we establish a continuity result for the equilibrium density with respect to the potential dependence.