Picard-Fuchs operators for octic arrangements I (The case of orphans)

Computing period integrals of rigid double octic Calabi-Yau threefolds with Picard-Fuchs operator

We present a method for numerical computation of period integrals of a rigid Calabi-Yau threefold using Picard-Fuchs operator of a one-parameter smoothing. Our method gives a possibility of computing the lattice of period integrals of a rigid double octic without any explicit knowledge of its geometric properties, employing only simple facts from the theory of Fuchsian equations and computations in MAPLE with a library for differential equations. As a surprising consequence we also get approximations of additional integrals related to a singular (nodal) model of considered Calabi-Yau threefold…

具有算术单值群的孤立Calabi-Yau三流形

Orphan Calabi-Yau threefold with arithmetic monodromy group

本文研究了孤立Calabi-Yau三流形单参数族Picard-Fuchs算子的单值群，为4阶双重八次孤立算子构造有理辛基，证明其单值群在Sp(4,Z)中稠密，并证明其中一个算子的单值群是算术的。

Coefficients of the monodromy matrices of one-parameter families of double octic Calabi-Yau threefolds at a half-conifold point

Doran and Morgan have introduced certain rational basis for the monodromy group of the Picard-Fuchs operator of a hypergeometric family of Calabi-Yau threefolds. In this paper we compute numerically the transition matrix between a generalization of the Doran-Morgan basis and the Frobenius basis at a half-conifold point of a one-parameter family of double octic Calabi-Yau threefolds. We identify the entries of this matrix as rational functions in the special values $L(f,1)$ and $L(f,2)$ of the corresponding modular form $f$ and one constant. We also present related results concerning the rank o…