Open-loop and closed-loop control of flying qubits

M Lucamarini (1, 2) , G Di Giuseppe (1, 2) , D Vitali (1) , P Tombesi (1, 2)

1 Physics Division
2 CriptoCam S.r.l

We describe two recent techniques, along with related experiments, to control and reduce the noise affecting a photon polarization qubit. The first is based on the open-loop " bang-bang " method, where suitably tailored pulses are implemented on the system to adverse polarization decoherence. This requires only passive elements when the physical system is a photon and the operation are performed in space rather than in time. The second technique is based on a closed-loop " asymmetric feedback ", where some quantities are measured and used for a real-time correction of the system dynamics. This technique necessarily requires an active electronics to work.

Mots clés: Physical Sciences

M Lucamarini, G Di Giuseppe, D Vitali, P Tombesi. Open-loop and closed-loop control of flying qubits. Journal of Physics B: Atomic, Molecular and Optical Physics, 2011, 44 (15), pp.154005. ⟨10.1088/0953-4075/44/15/154005⟩. ⟨hal-00642378⟩