Kavli Affiliate: Birgitta Whaley
| First 5 Authors: Sacha Greenfield, Leigh Martin, Felix Motzoi, K. Birgitta Whaley, Justin Dressel
| Summary:
We propose and analyze a protocol for stabilizing a maximally entangled state
of two noninteracting qubits using active state-dependent feedback from a
continuous two-qubit half-parity measurement in coordination with a concurrent,
non-commuting dynamical decoupling drive. We demonstrate the surprising result
that such a drive be simultaneous with the measurement and feedback, and can
also be part of the feedback protocol itself. We show that robust stabilization
with near-unit fidelity can be achieved even in the presence of realistic
nonidealities, such as time delay in the feedback loop, imperfect
state-tracking, inefficient measurements, and dephasing from 1/f-distributed
qubit-frequency noise. We mitigate feedback-delay error by introducing a
forward-state-estimation strategy in the feedback controller that tracks the
effects of control signals already in transit.
| Search Query: ArXiv Query: search_query=au:”Birgitta Whaley”&id_list=&start=0&max_results=3