Topological order in the insulating Josephson junction array

Benoît Douçot (1) , M. V. Feigel'Man , L. B. Ioffe

1 LPTHE - Laboratoire de Physique Théorique et Hautes Energies

We propose a Josephson junction array which can be tuned into an unconventional insulating state by varying external magnetic field. This insulating state retains a gap to half vortices; as a consequence, such array with non-trivial global geometry exhibits a ground state degeneracy. This degeneracy is protected from the effects of external noise. We compute the gaps separating higher energy states from the degenerate ground state and we discuss experiments probing the unusual properties of this insulator.

Domaines: Autre [cond-mat.other]

Benoît Douçot, M. V. Feigel'Man, L. B. Ioffe. Topological order in the insulating Josephson junction array. Physical Review Letters, 2003, 90, pp.107003. ⟨hal-00102557⟩