Fully frustrated Josephson junction ladders with Mobius boundary conditions as topologically protected qubits

TL;DR

This paper proposes a method to realize topologically protected qubits using fully frustrated Josephson junction ladders with Mobius boundary conditions, leveraging flux fractionalization and topological order for decoherence resistance.

Contribution

It introduces a novel approach to creating protected qubits by exploiting topological properties of Josephson junction ladders with Mobius boundary conditions.

Findings

Ground states exhibit topological order and flux fractionalization.

Adiabatic flux changes affect ground state stability and transformations.

Potential for robust, decoherence-resistant solid-state qubits.

Abstract

We show how to realize a ``protected'' qubit by using a fully frustrated Josephson Junction ladder (JJL) with Mobius boundary conditions. Such a system has been recently studied within a twisted conformal field theory (CFT) approach (Mod. Phys. Lett. A 15 (2000) 1679; Nucl. Phys. B 641 (2002) 547) and shown to develop the phenomenon of flux fractionalization (Eur. Phys. J. B 49 (2006) 83). The relevance of a ``closed'' geometry has been fully exploited in relating the topological properties of the ground state of the system to the presence of half flux quanta and the emergence of a topological order has been predicted (JSTAT (2005) P03006). In this letter the stability and transformation properties of the ground states under adiabatic magnetic flux change are analyzed and the deep consequences on the realization of a solid state qubit, protected from decoherence, are presented.