Avian Photoreceptor Patterns Represent a Disordered
Avian photoreceptor patterns represent a disordered hyperuniform solution to a multiscale packing problem Yang Jiao1,2, Timothy Lau3, Haralampos Hatzikirou4,5, Michael Meyer-Hermann4, Joseph C. Corbo3 and Salvatore Torquato1,6 1Princeton Institute of the Science and Technology of Materials, Princeton University, Princeton, NJ 2Materials Science and Engineering, Arizona State University, Tempe, AZ 3Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 4Department of Systems Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany 5Center for Advancing Electronics Dresden, TU Dresden, 01062, Dresden, Germany and 6Department of Chemistry, Department of Physics, Program in Computational and Applied Mathematics, Princeton University, Princeton, NJ (Dated: August 21, 2018) arXiv:1402.6058v1 [cond-mat.stat-mech] 25 Feb 2014 1 Abstract Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descrip- tors, we find that the disordered photoreceptor patterns are “hyperuniform” (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. A disordered hy- peruniform many-body system is an exotic state of matter that behaves like a perfect crystal or quasicrystal in the manner in which it suppresses large-scale density fluctuations and yet, like a liquid or glass, is statistically isotropic with no Bragg peaks.
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