Progress towards autonomous single photon loss error correction in a pair cat state (2/2)

The stabilization of Bosonic qubits in microwave cavities is a promising step towards implementing quantum error correction codes. The pair cat code, which utilizes a two mode entangled state, assures significant advantages over the previously implemented one-mode cat code for autonomous quantum error correction schemes [1]. A pair coherent state (PCS) forms the basis of this pair cat code where the error syndrome can be measured from the photon number difference (PND) between the two modes and then corrected [2]. We utilized a fluxonium qubit coupled to two 2D storage resonator modes in a 3D package to run this error correction process. To perform an error correction cycle, we use a two stage process to map single photon loss events, via PND, back to the original code state. This mapping is done with an ancilla that has negative dispersive shift matching with the two storage modes, thus giving first order fault tolerance to ancilla errors.