Orientation Asymmetric Surface Model for Membranes: Finsler Geometry Modeling

Abstract

We study triangulated surface models with nontrivial surface metrices for membranes. The surface model is defined by a mapping $\mathbf{r}$ from a two-dimensional parameter space M to the three-dimensional Euclidean space ${\mathbf{R}}^3$ . The metric variable $g_{ab}$ , which is always fixed to the Euclidean metric ${\delta }_{ab}$ , can be extended to a more general non-Euclidean metric on M in the continuous model. The problem we focus on in this paper is whether such an extension is well defined or not in the discrete model. We find that a discrete surface model with a nontrivial metric becomes well defined if it is treated in the context of Finsler geometry (FG) modeling, where triangle edge length in M depends on the direction. It is also shown that the discrete FG model is orientation asymmetric on invertible surfaces in general, and for this reason, the FG model has a potential advantage for describing real physical membranes, which are expected to have some asymmetries for orientation-changing transformations.