Pair correlation of $αn^θ$ for random $θ$

Abstract

For fixed $α>0$, we show that the sequence $\{αn^θ\}$ has Poissonian pair correlation for Lebesgue-almost all $θ\in (0,\frac{3}{5})\cup(3,\infty)$. This improves a result of Technau and Yesha, who proved the same for almost all $θ>7$. The approach of Technau and Yesha was based on a repulsion principle, which roughly allows one to estimate the variance of the pair correlation function using the fourth derivative of the phase. In our approach, we split the $θ$-integration in the variance into many short intervals and show that most of the integrals can be estimated using the first derivative. The problem is then reduced to several counting estimates, which we prove using moments of the Riemann zeta function and exponent pairs.