Quantum sensing of intermittent stochastic signals

Realistic quantum sensors face a trade-off between the number of sensors measured in parallel and the control and readout fidelity (F) across the ensemble. We investigate how the number of sensors and fidelity affect sensitivity to continuous and intermittent signals. For continuous signals, we find that increasing the number of sensors by 1/F2 for F<1 always recovers the sensitivity achieved when F=1. However, when the signal is intermittent, more sensors are needed to recover the sensitivity achievable with one perfect quantum sensor. We also demonstrate the importance of near-unity control fidelity and readout at the quantum projection noise limit by estimating the frequency components of a stochastic, intermittent signal with a single trapped ion sensor. Quantum sensing has historically focused on large ensembles of sensors operated far from the standard quantum limit. The results presented in this paper show that this is insufficient for quantum sensing of intermittent signals and reemphasizes the importance of the unique scaling of quantum projection noise near an eigenstate

Invited Article: Precision nanoimplantation of nitrogen vacancy centers into diamond photonic crystal cavities and waveguides

© 2016 Author(s). We demonstrate a self-aligned lithographic technique for precision generation of nitrogen vacancy (NV) centers within photonic nanostructures on bulk diamond substrates. The process relies on a lithographic mask with nanoscale implantation apertures for NV creation, together with larger features for producing waveguides and photonic nanocavities. This mask allows targeted nitrogen ion implantation, and precision dry etching of nanostructures on bulk diamond. We demonstrate high-yield generation of single NVs at pre-determined nanoscale target regions on suspended diamond waveguides. We report implantation into the mode maximum of diamond photonic crystal nanocavities with a single-NV per cavity yield of ∼26% and Purcell induced intensity enhancement of the zero-phonon line. The generation of NV centers aligned with diamond photonic structures marks an important tool for scalable production of optically coupled spin memories

Optical coherence of diamond nitrogen-vacancy centers formed by ion implantation and annealing

© 2019 American Physical Society. The advancement of quantum optical science and technology with solid-state emitters such as nitrogen-vacancy (NV) centers in diamond critically relies on the coherence of the emitters' optical transitions. A widely employed strategy to create NV centers at precisely controlled locations is nitrogen ion implantation followed by a high-temperature annealing process. We report on experimental data directly correlating the NV center optical coherence to the origin of the nitrogen atom. These studies reveal low-strain, narrow-optical-linewidth (1 GHz) and higher strain. The data show that the poor optical coherence of the NV centers formed from implanted nitrogen is not due to an intrinsic effect related to the diamond or isotope. These results have immediate implications for the positioning accuracy of current NV center creation protocols and point to the need to further investigate the influence of lattice damage on the coherence of NV centers from implanted ions

Caregivers' oral health literacy and their young children's oral health-related quality-of-life

OBJECTIVES: To investigate the association of caregivers’ oral health literacy (OHL) with their children's oral health related-quality of life (C-OHRQoL) and explore literacy as a modifier in the association between children's oral health status (COHS) and C-OHRQoL. METHODS: We relied upon data from structured interviews with 203 caregivers of children ages 3-5 from the Carolina Oral Health Literacy (COHL) Project. Data were collected for OHL using REALD-30, caregiver-reported COHS using the NHANES-item, and COHRQoL using the Early Childhood Oral Health Impact Scale (ECOHIS). We also measured oral health behaviors (OHBs) and socio-demographic characteristics and calculated overall/stratified summary estimates for OHL and C-OHRQoL. We computed Spearman's rho and 95% confidence limits (CL) as measures of correlation of OHL/COHS with C-OHRQoL. To determine whether OHL modified the association between COHS and C-OHRQoL, we compared literacy-specific summary and regression estimates. RESULTS: Reported COHS was: excellent—50%, very good—28%, good—14%, fair—6%, poor—2%. The aggregate C-OHRQoL mean score was 2.0 (95% CL:1.4, 2.6), and the mean OHL score 15.9 (95% CL:15.2, 16.7). There was an inverse relationship between COHS and C-OHRQoL: rho=-0.32 (95% CL:-0.45, -0.18). There was no important association between OHL and C-OHRQoL; however, deleterious OHBs were associated with worse C-OHRQoL. Literacy-specific linear and Poisson regression estimates of the association between COHS and C-OHRQoL departed from homogeneity (Wald X(2) P<0.2). CONCLUSION: In this community-based sample of caregiver/child dyads, we found a strong correlation between OHS and C-OHRQoL. The association's magnitude and gradient were less pronounced among caregivers with low literacy