Quantum control and error correction with two bosonic modes (2/2)

Encoding quantum information in bosonic modes is a promising way to realize error-corrected logical qubits for fault tolerant quantum computing. In recent years there has been a lot of progress with qubits encoded in states of single bosonic modes. However, logical qubits encoded in the joint Hilbert space of two bosonic modes offer simpler error syndromes in comparison. Advantageously, the error syndromes for these codes can be engineered in such a way that they are transparent to ancilla errors. In our experiment, we explore these two-mode bosonic encodings for quantum error correction in 3D superconducting microwave architecture. We use a cross-Kerr tuning parametric process, which was recently demonstrated in a single mode system, to dynamically modify the interaction Hamiltonian between the bosonic modes and an ancilla transmon. We use this method to also perform joint-Wigner tomography on the two-mode states.

Part-two of this two-part presentation will address encoding and controlling logical qubits in the joint Hilbert space of the modes.