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Résumé |
Abstract: Entangled states constitute a key resource in quantum cryptography, quantum computation and quantum sensing. It has generally been assumed that the creation of such states requires the system to avoid contact with a dissipative environment, and the suppression of all sources of dephasing. Some recent theoretical studies have shown, however, that dissipative interactions combined with an adequately chosen drive can be employed to preserve coherence. Following these ideas, we have built experimentally an autonomous feedback scheme that counteracts both dissipation and dephasing. This led to the stabilization of an entangled Bell state of a quantum register of two superconducting qubits for an arbitrary time [1]. Furthermore, fidelity of the Bell state can be increased by continuously monitoring one dissipative channel involved in the stabilization. The general approach we are following may help building a logical qubit holding quantum information in a fault-tolerant way and with minimal hardware [2].
[1] Shankar et al., Nature 504, 419 (2013)
[2] Mirrahimi et al., New J. Phys. 16, 045014 (2014) |
