A cyclotomic gluing construction for lattice sphere packings

Abstract

For a positive integer $d$, let $Δ_d^L$ denote the supremum of the densities of lattice sphere packings in $\mathbb R^d$. We prove that, for every sufficiently large $d$, $Δ_d^L \gg d^2\log\log d\,2^{-d}$. Abuya-Gargava-Zhao obtained the same bound along a sparse sequence of dimensions by combining Venkatesh's cyclotomic symmetries with Klartag's stochastic ellipsoid method. We introduce a multi-cyclotomic gluing construction that allows this argument to work in every sufficiently large dimension.