Bandwidth-Limited Control and Ringdown Suppression in High-Q Resonators
arXiv:1207.1139 · doi:10.1016/j.jmr.2012.10.011
Abstract
We describe how the transient behavior of a tuned and matched resonator circuit and a ringdown suppression pulse may be integrated into an optimal control theory (OCT) pulse-design algorithm to derive control sequences with limited ringdown that perform a desired quantum operation in the presence of resonator distortions of the ideal waveform. Inclusion of ringdown suppression in numerical pulse optimizations significantly reduces spectrometer deadtime when using high quality factor (high-Q) resonators, leading to increased signal-to-noise ratio (SNR) and sensitivity of inductive measurements. To demonstrate the method, we experimentally measure the free-induction decay of an inhomogeneously broadened solid-state free radical spin system at high Q. The measurement is enabled by using a numerically optimized bandwidth-limited OCT pulse, including ringdown suppression, robust to variations in static and microwave field strengths. We also discuss the applications of pulse design in high-Q resonators to universal control of anisotropic-hyperfine coupled electron-nuclear spin systems via electron-only modulation even when the bandwidth of the resonator is significantly smaller than the hyperfine coupling strength. These results demonstrate how limitations imposed by linear response theory may be vastly exceeded when using a sufficiently accurate system model to optimize pulses of high complexity.
20 pages, 5 figures; Replaced with version accepted for publication and added journal reference
References in corpus (7)
- Quantum computing with an electron spin ensemble
- Liquid State NMR as a Test-bed for Developing Quantum Control Methods
- Universal Control of Nuclear Spins Via Anisotropic Hyperfine Interactions
- Coherence and control of quantum registers based on electronic spin in a nuclear spin bath
- Application of Optimal Control to CPMG Refocusing Pulse Design
- Switched Control of Electron Nuclear Spin Systems
- Fidelity enhancement by logical qubit encoding