Événements

séminaire de l'IQ : Joachim Cohen

Date : 21 février 2019 12:00

Type : Séminaires

Lieu : D3-2041

Joachim Cohen, QUANTIC project-team, INRIA Paris, France Titre: Fault-tolerant quantum error correction with cat qubits Résumé: In a quantum error correction (QEC) scheme, the measurement of an error syndrome should be performed in a quantum non-demolition manner. In particular, such a measurement should not introduce additional error channels which are not correctable by the QEC scheme. Here, we ensure such a robustness by designing a specific interaction between the data qubits and the readout modes that preserves the degeneracy of the measured observable. Such a coupling makes the system tolerant to possible errors occurring on the readout modes. More precisely, we propose to perform quantum non-demolition measurement of photon-number parity in a microwave cavity. This corresponds to the error syndrome in a class of error correcting codes called the cat codes, which have recently proven to be efficient and versatile for quantum information processing. In our design, we exploit the strongly nonlinear Hamiltonian of a high-impedance Josephson circuit, coupling a high-Q cavity mode to a low-Q readout one. Next, as a follow up of this result, we present a continuous and autonomous fault-tolerant QEC scheme using the cat code. This scheme provides a robust protection against dominant error channels in the presence of multi-photon driven dissipation.

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