String loop corrected hypermultiplet moduli spaces
Daniel Robles-Llana, Frank Saueressig, Stefan Vandoren
TL;DR
The authors determine the perturbative string loop corrections to the hypermultiplet moduli space of type II strings on a generic CY$_3$, showing the HM geometry is quaternion‑Kähler and globally encoded by a single function $H(oldsymbol{ exteta})$. By employing the off‑shell superconformal tensor multiplet formalism and the c‑map, they derive a one‑loop deformation $H^{ m qc}(oldsymbol{ exteta}) = rac{F(oldsymbol{ exteta}^oldsymbol{ta})}{oldsymbol{ exteta}^0} - 4 c D(oldsymbol{ exteta}^oldsymbol{ta}) oldsymbol{ exteta}^0 oldsymbol{ta}^0 oldsymbol{}oldsymbol{ exteta}^0$ that simultaneously encodes TM and HM loop corrections, with the constants fixed by matching to known string amplitudes and parity, yielding a universal one‑loop correction proportional to the CY Euler characteristic. They further argue for a non‑renormalization theorem that higher loop corrections are absent in this perturbative sector, at least under a contour choice that encircles the origin in the auxiliary complex plane. The results generalize the universal hypermultiplet corrections and provide a controlled, symmetry‑driven framework to study perturbative corrections to HM moduli spaces, with potential implications for orientifolds, flux compactifications, and dual heterotic descriptions.
Abstract
Using constraints from supersymmetry and string perturbation theory, we determine the string loop corrections to the hypermultiplet moduli space of type II strings compactified on a generic Calabi-Yau threefold. The corresponding quaternion-Kahler manifolds are completely encoded in terms of a single function. The latter receives a one-loop correction and, using superspace techniques, we argue for the existence of a non-renormalization theorem excluding higher loop contributions.
