Quantum Symmetries and Stringy Instantons

Abstract

The quantum symmetry of many \LG\ orbifolds appears to be broken by Yang-Mills instantons. However, isolated Yang-Mills instantons are not solutions of string theory: They must be accompanied by gauge anti-instantons, gravitational instantons, or topologically non-trivial configurations of the $H$ field. We check that the configurations permitted in string theory do in fact preserve the quantum symmetry, as a result of non-trivial cancellations between symmetry breaking effects due to the various types of instantons. These cancellations indicate new constraints on \LG\ orbifold spectra and require that the dilaton modulus mix with the twisted moduli in some \LG\ compactifications. We point out that one can find similar constraints at all fixed points of the modular group of the moduli space of vacua.

14pp, harvmac, PUPT--1464

References in corpus (5)

• Strong-Weak Coupling Duality in Four Dimensional String Theory
• Duality Anomaly Cancellation, Minimal String Unification and the Effective Low-Energy Lagrangian of 4-D Strings
• (0,2) Landau-Ginzburg Theory
• Computing the Complete Massless Spectrum of a Landau-Ginzburg Orbifold
• Geometry of (0,2) Landau-Ginzburg Orbifolds

Cited by in corpus (11)

• World-sheet Stability of (0,2) Linear Sigma Models
• Some Three Generation (0,2) Calabi-Yau Models
• On the Instanton Contributions to the Masses and Couplings of $E_6$ Singlets
• Sheaves on Toric Varieties for Physics
• Notes on nonabelian (0,2) theories and dualities
• Gauged Linear Sigma Models for toroidal orbifold resolutions
• Heterotic orbifold resolutions as (2,0) gauged linear sigma models
• Exploring the Moduli Space of (0,2) Strings
• Some Features of (0,2) Moduli Space
• Notes on Heterotic Compactifications
• Tracing symmetries and their breakdown through phases of heterotic (2,2) compactifications