Superconductor-ferromagnet junction phase qubit

TL;DR

This paper introduces a novel superconductor-ferromagnet junction phase qubit that leverages the 0 and π phase states for quantum computing, offering enhanced decoherence resistance and scalable measurement schemes.

Contribution

It presents a new qubit design based on SIFIS junctions with a superposition of phase states, and proposes methods for scalable measurement and tunable coupling.

Findings

Qubit operates via gate voltage on ferromagnet

Insensitive to common decoherence sources

Scalable measurement and tunable coupling schemes

Abstract

We propose a scheme for a phase qubit in an SIFIS junction, consisting of bulk superconductors (S), a proximity-induced ferromagnet (F), and insulating barriers (I). The qubit state is constituted by 0 and $\pi$ phase states of the junction, in which the charging energy of the junction leads to the superposition of the two states. The qubit is operated by the gate voltage applied to the ferromagnet, and insensitive to the decoherence sources existing in other superconducting qubits. We discuss a scalable scheme for qubit measurement and tunable two-qubit coupling.