Towards Scalable Bosonic Quantum Error Correction

Abstract

We review some of the recent efforts in devising and engineering bosonic qubits for superconducting devices, with emphasis on the Gottesman-Kitaev-Preskill (GKP) qubit. We present some new results on decoding repeated GKP error correction using finitely-squeezed GKP ancilla qubits, exhibiting differences with previously studied stochastic error models. We discuss circuit-QED ways to realize CZ gates between GKP qubits and we discuss different scenario's for using GKP and regular qubits as building blocks in a scalable superconducting surface code architecture.

54 pages; 18 Figs; 3 Appendices; invited topical review for Quantum Science & Technology. v2 has a few corrections and some additional references. v3 has a few additional corrections and references