Laminating lattices with symmetrical glue

Abstract

We use the automorphism group Aut(H), of holes in the lattice L8=A2⊕A2⊕D4, as the starting point in the construction of sphere packings in 10 and 12 dimensions. A second lattice, L4=A2⊕A2, enters the construction because a subgroup of Aut(L4) is isomorphic to Aut(H). The lattices L8 and L4, when glued together through this relationship, provide an alternative construction of the laminated lattice in twelve dimensions with kissing number 648. More interestingly, the action of Aut(H) on L4 defines a pair of invariant planes through which dense, non-lattice packings in 10 dimensions can be constructed. The most symmetric of these is aperiodic with center density 1/32. These constructions were prompted by an unexpected arrangement of 378 kissing spheres discovered by a search algorithm. © 2008 Springer Science+Business Media, LLC.