Kodaira-Spencer Theory of Gravity and Exact Results for Quantum String Amplitudes

TL;DR

This paper develops techniques to compute higher loop string amplitudes in twisted N=2 theories, revealing an anomaly at each genus and connecting topological string theory with Calabi-Yau geometry and superpotential corrections.

Contribution

It introduces a master anomaly equation for higher genus amplitudes and links Kodaira-Spencer theory to topological string computations in Calabi-Yau compactifications.

Findings

Derived all-genus anomaly equations for N=2 string theories

Connected topological amplitudes to holomorphic curve counting in Calabi-Yau manifolds

Reinterpreted topological amplitudes as superpotential corrections in 4D effective theories

Abstract

We develop techniques to compute higher loop string amplitudes for twisted $N=2$ theories with $\hat c=3$ (i.e. the critical case). An important ingredient is the discovery of an anomaly at every genus in decoupling of BRST trivial states, captured to all orders by a master anomaly equation. In a particular realization of the $N=2$ theories, the resulting string field theory is equivalent to a topological theory in six dimensions, the Kodaira--Spencer theory, which may be viewed as the closed string analog of the Chern--Simon theory. Using the mirror map this leads to computation of the `number' of holomorphic curves of higher genus curves in Calabi--Yau manifolds. It is shown that topological amplitudes can also be reinterpreted as computing corrections to superpotential terms appearing in the effective 4d theory resulting from compactification of standard 10d superstrings on the corresponding $N=2$ theory. Relations with $c=1$ strings are also pointed out.