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  1. Abstract

    We improve the previously best known upper bounds on the sizes of$$\theta $$θ-spherical codes for every$$\theta <\theta ^*\approx 62.997^{\circ }$$θ<θ62.997at least by a factor of 0.4325, in sufficiently high dimensions. Furthermore, for sphere packing densities in dimensions$$n\ge 2000$$n2000we have an improvement at least by a factor of$$0.4325+\frac{51}{n}$$0.4325+51n. Our method also breaks many non-numerical sphere packing density bounds in smaller dimensions. This is the first such improvement for each dimension since the work of Kabatyanskii and Levenshtein (Problemy Peredači Informacii 14(1):3–25, 1978) and its later improvement by Levenshtein (Dokl Akad Nauk SSSR 245(6):1299–1303, 1979) . Novelties of this paper include the analysis of triple correlations, usage of the concentration of mass in high dimensions, and the study of the spacings between the roots of Jacobi polynomials.

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