Compact Formulas for the Completed Mock Modular Forms
Abstract
In this paper we present a new compact expression of the elliptic genus of SL(2)/U(1)-supercoset theory by making use of the `spectral flow method' of the path-integral evaluation. This new expression is written in a form like a Poincare series with a non-holomorphic Gaussian damping factor, and manifestly shows the modular and spectral flow properties of a real analytic Jacobi form. As a related problem, we present similar compact formulas for the modular completions of various mock modular forms which appear in the representation theory of N=2,4 superconformal algebras. We further discuss the generalization to the cases of arbitrary spin-structures, that is, the world-sheet fermions with twisted boundary conditions parameterized by a continuous parameter. This parameter is naturally identified with the `u-variable' in the Appell-Lerch sum.
Cite
@article{arxiv.1407.7721,
title = {Compact Formulas for the Completed Mock Modular Forms},
author = {Tohru Eguchi and Yuji Sugawara},
journal= {arXiv preprint arXiv:1407.7721},
year = {2015}
}
Comments
1+31 pages, no figure; v2 minor corrections, typos corrected, version to appear in JHEP