Topological order in frustrated Josephson junction arrays

We show that electrically and magnetically frustrated Josephson junction arrays (JJAs) realize topological order with a non-trivial ground-state degeneracy on manifolds with non-trivial topology. The low-energy theory has the same gauge dynamics of the unfrustrated JJAs but for different, fractional degrees of freedom, a principle reminescent of Jain's composite electrons in the fractional quantum Hall effect. Copyright (C) EPLA, 2008.