English

Dense ball packings by tube manifolds as new models for hyperbolic crystallography

Metric Geometry 2023-10-03 v2 Geometric Topology

Abstract

We intend to continue our previous papers (\cite{MSz17} and \cite{MSz18}, as indicated there) on dense ball packing hyperbolic space \HYP\HYP by equal balls, but here with centres belonging to different orbits of the fundamental group Cw(2z,3z\bNCw(2z, 3 \le z \in \bN, odd number), of our new series of {\it tube or cobweb manifolds} Cw=\HYP/\BCwCw = \HYP/\BCw with zz-rotational symmetry. As we know, \BCw\BCw is a fixed-point-free isometry group, acting on \HYP\HYP discontinuously with appropriate tricky fundamental domain CwCw, so that every point has a ball-like neighbourhood in the usual factor-topology. Our every Cw(2z)Cw(2z) is minimal, i.e. does not cover regularly a smaller manifold. It can be derived by its general symmetry group \BW(u,v,w=u)\BW(u, v, w = u) that is a complete Coxeter orthoscheme reflection group, extended by the half-turn \Bh\Bh (03,12)(0 \leftrightarrow 3, 1 \leftrightarrow 2) of the complete orthoscheme A0A1A2A3b0b1b2b3A_0A_1A_2A_3 \sim b_0b_1b_2b_3 (Fig.~1). The vertices A0A_0 and A3A_3 are outer points of the \HYP\HYP, as 1/u+1/v1/21/u + 1/v \le 1/2 is required, 3u=w,v3 \le u = w, v for the above orthoscheme parameters. The situation is described first in Figure 1 of the half trunc-orthoscheme WW and its usual extended Coxeter diagram, moreover, by the scalar product matrix (bij)=(\Bbi,\Bbj)(b^{ij}) = (\langle \Bb^i, \Bb^j \rangle) in formula (1.1) and its inverse (Ajk)=(\BAj,\BAk)(A_{jk}) = (\langle \BA_j, \BA_k \rangle) in (1.3). These will describe the hyperbolic angle and distance metric of the half trunc-orthoscheme WW, then its ball packings, densities, then those of the manifolds Cw(2z)Cw(2z). As first results we concentrate only on particular constructions by computer for probable material model realizations, atoms or molekules by equal balls, for general W(u;v;w=u)W(u;v;w=u) as well, summarized at the end of our paper.

Keywords

Cite

@article{arxiv.2309.15168,
  title  = {Dense ball packings by tube manifolds as new models for hyperbolic crystallography},
  author = {Emil Molnár and Jenő Szirmai},
  journal= {arXiv preprint arXiv:2309.15168},
  year   = {2023}
}

Comments

24 pages, 7 figures