Ian Walmsley

Experimental coherent-feedback quantum control: opportunities and challenges
(Tuesday, 26 August, 11:15-12:00)

Abstract:

Coherent control of quantum systems uses the constructive or destructive interference between pathways to manipulate the evolution of the system. The success of any coherent manipulation of the dynamics depends on maintaining the quantum phase relationships between the different parts of the system. The inevitable interaction of any real system with its environment will corrupt the unitary evolution and prevent the coherent control from reaching its objective. We present recent results on the application of closed loop control methods to mitigate the effects of the environment on coherent superposition states, and show experimentally that a coherence surrogate may be effective for identifying the states of the system least sensitive to dephasing. Further we show how a complete map for the system dynamics may be constructed with a small dataset, based on a minimal prior assumption about the system-reservoir coupling.