2008/04/02 by Jonathan McDonald, Jonathan R. McDonald, McDonald, Jonathan R. +2
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Noncommutative and Quantum Gravity Theories #Relativity and Gravitational Theory #gr-qc
paper · pdf · doi:10.48550/arxiv.0804.0279
25 pages, 12 figures, submitted to "Tessellations in the Science: Virtues, Techniques and Applications of Geometric Tilings," ed. R. van de Weijgaert, G. Vegter, J. Ritzerveld and V. Icke
arxiv created 2008/04/02 · openalex publication_date 2008/04/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In 1961 Tullio Regge provided us with a beautiful lattice representation of Einstein's geometric theory of gravity. This Regge Calculus (RC) is strikingly different from the more usual finite difference and finite element discretizations of gravity. In RC the fundamental principles of General Relativity are applied directly to a tessellated spacetime geometry. In this manuscript, and in the spirit of this conference, we reexamine the foundations of RC and emphasize the central role that the Voronoi and Delaunay lattices play in this discrete theory. In particular we describe, for the first time, a geometric construction of the scalar curvature invariant at a vertex. This derivation makes use of a new fundamental lattice cell built from elements inherited from both the simplicial (Delaunay) spacetime and its circumcentric dual (Voronoi) lattice. The orthogonality properties between these two lattices yield an expression for the vertex-based scalar curvature which is strikingly similar to the corresponding and more familiar hinge-based expression in RC (deficit angle per unit Voronoi dual area). In particular, we show that the scalar curvature is simply a vertex-based weighted average of deficits per weighted average of dual areas. What is most striking to us is how naturally spacetime is represented by Voronoi and Delaunay structures and that the laws of gravity appear to be encoded locally on the lattice spacetime with less complexity than in the continuum, yet the continuum is recovered by convergence in mean. Perhaps these prominent features may enable us to transcend the details of any particular discrete model gravitation and yield clues to help us discover how we may begin to quantize this fundamental interaction.