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Breakdown of Duality in (0,2) Superstring Models

Jens Erler
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Abstract

After pointing out the role of the compactification lattice for spectrum calculations in orbifold models, I discuss modular discrete symmetry groups for $Z_N$ or\-bi\-folds. I consider the $Z_7$ orbifold as a nontrivial example of a (2,2) model and give the generators of the modular group for this case, which does not contain $[SL(2,{\bf Z})]^3$ as had been speculated. I also discuss how to treat cases where quantized Wilson lines are present. I consider in detail an example, demonstrating that quantized Wilson lines affect the modular group in a nontrivial manner. In particular, I show that it is possible for a Wilson line to break $SL(2,{\bf Z})$.}

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Jens Erler. 1993-06-16. Breakdown of Duality in (0,2) Superstring Models. https://arxiv.org/abs/hep-th/9306074

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