NMon: enhanced transmon qubit based on parallel arrays of Josephson junctions

We introduce a novel superconducting qubit architecture utilizing parallel arrays of Josephson junctions. This design offers a substantialy improved relative anharmonicity, typically within the range of |αᵣ| ≈ 0.1 - 0.3, while maintaining transition matrix elements in both the charge and flux channels that are on par with those of transmon qubits. Our proposed device also features exceptional tunability and includes a parameter regime akin to an enhanced version of the fluxonium qubit. Notably, it enables an additional order of magnitude reduction in matrix elements influenced by flux noise, thus further enhancing its suitability for quantum information processing applications.