Lattice Surgery Realized on Two Distance-Three Repetition Codes with Superconducting Qubits

Recent experiments have progressed towards this by demonstrating sufficiently low error rates for state preservation of a single logical qubit. However, quantum computation algorithms also require that these logical qubits can be entangled and that gate operations can be performed on them.

Lattice surgery is a technique that offers a practical approach for implementing such gates, particularly in planar quantum processor layouts. Here, we demonstrate lattice surgery between two distance-three repetition-code qubits by splitting a single distance-three surface-code qubit. Using a quantum circuit that is fault-tolerant for bit-flip errors, we achieve an improvement in the value of the decoded ZZ logical two-qubit observable compared to a similar non-encoded circuit.