title: Counterintuitive ground states in soft-core models.
abstract: It is well known that statistical mechanics systems exhibit subtle behavior in high dimensions. In this paper, we show that certain natural soft-core models, such as the Gaussian core model, have unexpectedly complex ground states even in relatively low dimensions. Specifically, we disprove a conjecture of Torquato and Stillinger, who predicted that dilute ground states of the Gaussian core model in dimensions 2 through 8 would be Bravais lattices. We show that in dimensions 5 and 7, there are in fact lower-energy non-Bravais lattices. (The nearest three-dimensional analog is the hexagonal close-packing, but it has higher energy than the face-centered cubic lattice.) We believe these phenomena are in fact quite widespread, and we relate them to decorrelation in high dimensions.
authors.affiliation: Microsoft Research New England, One Memorial Drive, Cambridge, Massachusetts 02142, USA. cohn@microsoft.com
authors.forename: Henry
authors.initials: H
authors.lastname: Cohn
authors.forename: Abhinav
authors.initials: A
authors.lastname: Kumar