Meromorphic modular forms and the three-loop equal-mass banana integral

Modular Forms and Three Loop Superstring Amplitudes

We study a proposal of D’Hoker and Phong for the chiral superstring measure for genus three. A minor modification of the constraints they impose on certain Siegel modular forms leads to a unique solution. We reduce the problem of finding these modular forms, which depend on an even spin structure, to finding a modular form of weight 8 on a certain subgroup of the modular group. An explicit form...

The Mordell Integral, Quantum Modular Forms, and Mock Jacobi Forms

It is explained how the Mordell integral ∫ R e −2πzx cosh(πx) dx unifies the mock theta functions, partial (or false) theta functions, and some of Zagier’s quantum modular forms. As an application, we exploit the connections between q-hypergeometric series and mock and partial theta functions to obtain finite evaluations of the Mordell integral for rational choices of τ and z. 1. The Mordell In...

MAT1200: Modular Forms of Half Integral Weight

On “good” Half-integral Weight Modular Forms

If k is a positive integer, let Sk(N) denote the space of cusp forms of weight k on Γ1(N), and let S k (N) denote the subspace of Sk(N) spanned by those forms having complex multiplication (see [Ri]). For a non-negative integer k and any positive integer N ≡ 0 (mod 4), let Mk+ 2 (N) (resp. Sk+ 2 (N)) denote the space of modular forms (resp. cusp forms) of half-integral weight k + 12 on Γ1(N). S...

Coefficients of Half-integral Weight Modular Forms

In this paper we study the distribution of the coefficients a(n) of half integral weight modular forms modulo odd integers M . As a consequence we obtain improvements of indivisibility results for the central critical values of quadratic twists of L-functions associated with integral weight newforms established in [O-S]. Moreover, we find a simple criterion for proving cases of Newman’s conject...