Continuous dynamical decoupling magnetometry

Abstract

Solid-state qubits hold the promise to achieve unmatched combination of sensitivity and spatial resolution. To achieve their potential, the qubits need however to be shielded from the deleterious effects of the environment. While dynamical decoupling techniques can improve the coherence time, they impose a compromise between sensitivity and bandwidth, since to higher decoupling power correspond higher frequencies of the field to be measured. Moreover, the performance of pulse sequences is ultimately limited by control bounds and errors. Here we analyze a versatile alternative based on continuous driving. We find that continuous dynamical decoupling schemes can be used for AC magnetometry, providing similar frequency constraints on the AC field and improved sensitivity for some noise regimes. In addition, the exibility of phase and amplitude modulation could yield superior robustness to driving errors and a better adaptability to external experimental scenarios

Isotope engineering of silicon and diamond for quantum computing and sensing applications

“…Because an NV electron is spatially confined within 1 nm, it can be placed within a few nanometers from the target. Therefore, research leading to the application of NV centers for magnetic sensing has become very active recently [117][118][119][120][121][122][123][124][125][126][127][128] and the use of such sensors in solid-state physics research is [98] Figure 7. Sensing the magnetic field that arose from the nuclear spins of a molecule using (a) a single NV center embedded in a diamond substrate and (b) a single NV center embedded in the tip of a diamond cantilever.…”

Decay of the rotary echoes for the spin of a nitrogen-vacancy center in diamond

“…Influence of the relevant dilute dipolar-coupled spin bath on the NV spin can be modelled as a random time-varying magnetic field obeying the statistics of the Ornstein-Uhlenbeck process (stationary Gaussian Markovian process). 11,47,49,50,61,62 Previous studies of the rotary echo decay of the NV spin, 48,49,58 while providing important insights, were restricted to low orders of the cumulant expansion of the evolution operator, or to the case of static bath. Our study avoids these limitation.…”

“…25,[39][40][41][42][43][44][45][46] At the same time, an alternative approach based on the continuous dynamical decoupling has been extensively investigated. 11,[47][48][49][50][51][52][53][54][55][56][57][58] Within this approach, strong resonant driving is applied to the NV center. The resulting fast Rabi oscillations of the NV spin, similarly to the flip-flops induced by the decoupling pulses, average out the interaction with the environment, and significantly extend the spin coherence time.…”

“…Robustness of the continuous decoupling with respect to these experimental imperfections can be greatly improved by periodically inverting the driving field (switching the driving field phase by 180 • ). 48,49,[58][59][60] The resulting signal demonstrates a series of so-called rotary echoes, which decay much slower than the regular Rabi oscillations, and may be utilized for precise nanoscale sensing. 48,49,58 Although the rotary echo protocol requires constant driving of the NV spin, and therefore much larger dissipated power, it has an additional advantage over the pulse-based dynamical decoupling: an experimentalist can independently control both the strength of driving and the driving reversal time.…”

Radio-Frequency Magnetometry Using a Single Electron Spin

“…Our approach relies on spin locking [10][11][12] and is illustrated in Fig. 1: In a spin-lock experiment, a resonant microwave field is applied in-phase with the coherent Larmor precession of the spin.…”