Asymmetric orbifold models of non-supersymmetric heterotic strings

We investigate asymmetric orbifold models constructed from non-supersymmetric heterotic strings. We systematically classify the asymmetric orbifold models with standard embeddings and present a list of asymmetric orbifolds which are geometrically interpreted as toroidal compactifications of non-supersymmetric heterotic strings. By studying non-standard embedding models, we also construct examples of the supersymmetric asymmetric orbifold models based on non-supersymmetric heterotic strings.