Encoding qubits in Bloch states of superconducting devices*

We describe two related superconducting circuits, the transmon [1] and the dualmon [2] in terms of Bloch states that reflect periodic symmetries in their Hamiltonians. We use these two systems to illustrate a new scheme for encoding a qubit into superconducting qubits, using states in the lowest Bloch band. We discuss how these states are likely to be extremely robust against relaxation and noise, and suggest possible gates for controlling the state of such systems.

[1] "Building a bigger Hilbert space for superconducting devices, one Bloch state at a time", Dat Thanh Le, Jared H. Cole, T. M. Stace, http://arxiv.org/abs/1910.10919
[2] "A Doubly non-Linear Superconducting Qubit", Dat Thanh Le, Arne Grimsmo, Clemens Mueller, and T. M. Stace, http://arxiv.org/abs/1904.01843