Paper detail

Dense packings via lifts of codes to division rings

We obtain algorithmically effective versions of the dense lattice sphere packings constructed from orders in $\mathbb{Q}$-division rings by the first author. The lattices in question are lifts of suitable codes from prime characteristic to orders $\mathcal{O}$ in $\mathbb{Q}$-division rings and we prove a Minkowski--Hlawka type result for such lifts. Exploiting the additional symmetries under finite subgroups of units in $\mathcal{O}$, we show this leads to effective constructions of lattices approaching the best known lower bounds on the packing density $Δ_n$ in a variety of new dimensions $n$. This unifies and extends a number of previous constructions.