Non-Supersymmetric String-String Dualities via Enriques Surfaces

We propose non-supersymmetric analogues of 6d N=2 Type II/heterotic dualities via a quotient of a K3 surface: an Enriques surface. We start from Type~II strings on a K3 surface and construct orbifold theories using an involution of K3. We extract the massless and tachyonic spectra and identify the moduli spaces locally. We further reinterpret the constructions as Type 0A/0B strings compactified on an Enriques surface, and argue that the theories are dual to recently constructed non-supersymmetric heterotic asymmetric orbifolds.