Physical Review A - Atomic, Molecular, and Optical Physics
We explore the physical limits of pulsed dynamical decoupling methods for decoherence control as determined by finite timing resources. By focusing on a decohering qubit controlled by arbitrary sequences of π pulses, we establish a nonperturbative quantitative upper bound to the achievable coherence for specified maximum pulsing rate and noise spectral bandwidth. We introduce numerically optimized control “bandwidth-adapted” sequences that saturate the performance bound and show how they outperform existing sequences in a realistic excitonic-qubit system where timing constraints are significant. As a by-product, our analysis reinforces the impossibility of fault-tolerance accuracy thresholds for generic open quantum systems under purely reversible error control.
Khodjasteh, Kaveh; Erdélyi, Támas; and Viola, Lorenza, "Limits on Preserving Quantum Coherence Using Multipulse Control" (2011). Open Dartmouth: Faculty Open Access Articles. 2889.