Improved interspecies optical clock comparisons through differential spectroscopy

Kim, May E.; McGrew, William F.; Nardelli, Nicholas V.; Clements, Ethan; Hassan, Youssef S.; Zhang, X.; Valencia, J. L.; Leopardi, Holly; Hume, David; Fortier, Tara M.; Ludlow, Andrew D.; Leibrandt, David R.

doi:10.1038/s41567-022-01794-7

Cited by 14 publications

(10 citation statements)

References 32 publications

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“…An attractive feature of this protocol is that it does not necessitate interactions (two-qubit gates) or individual spectator qubit control, which reduces hardware complexity. The use of spectator qubits for noise measurements may provide opportunities in quantum sensing and metrology ( 22 , 35 , 36 ) and for improving clock coherence within a single device through differential spectroscopy between the data and spectator qubits ( 37 ). Whereas in this work we focused on global noise, arrays of spectator qubits may also enable the detection of spatially varying noise fields that can be suppressed by local qubit addressing ( 24 ).…”

Section: Discussion and Outlookmentioning

confidence: 99%

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Singh

Bradley

Anand

et al. 2023

Science

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Scaling up invariably error-prone quantum processors is a formidable challenge. Although quantum error correction ultimately promises fault-tolerant operation, the required qubit overhead and error thresholds are daunting. In a complementary proposal, co-located, auxiliary ‘spectator’ qubits act as in-situ probes of noise, and enable real-time, coherent corrections of data qubit errors. We use an array of cesium spectator qubits to correct correlated phase errors on an array of rubidium data qubits. By combining in-sequence readout, data processing, and feed-forward operations, these correlated errors are suppressed within the execution of the quantum circuit. The protocol is broadly applicable to quantum information platforms, and establishes key tools for scaling neutral-atom quantum processors: mid-circuit readout of atom arrays, real-time processing and feed-forward, and coherent mid-circuit reloading of atomic qubits.

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Section: Discussion and Outlookmentioning

confidence: 99%

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Singh

Bradley

Anand

et al. 2023

Science

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“…Also shown for comparison in Figure 9 is the current best stability achieved for an inter-species optical clock comparison, [70] which yielded a 1-s stability near 2 × 10 −16 . As seen from the figure, the current level of the Doppler stabilized fibre links and optical synthesis with the OFC is sufficient to support the current best atomic clock comparisons.…”

Section: Stability and Accuracy In Optical Frequency Synthesismentioning

confidence: 98%

“…Currently, the 1-s instability of most inter-species clock comparisons is limited by the clock local oscillator. The development of cryogenic optical reference cavities [48,71] and differential spectroscopy of atomic clocks [70] offer a path toward lower clock and measurement instability, respectively. As a result, optical synthesis with the OFC, as well as the dissemination of clock signals via optical fibre, will also need to improve to achieve better short term instability.…”

Section: Stability and Accuracy In Optical Frequency Synthesismentioning

confidence: 99%

“…Optical beat note between two 100 m long 1070 nm fibre links (blue trace). The current best inter‐species optical clock comparison [ 70 ] between the 27 Al+ ion clock and 171 Yb optical lattice clock using differential spectroscopy (red points) fit to a white frequency noise trend line (

1.97\ensuremath{\times{}}{10}^{-16}{\tau}^{-1/2}

), shown with red dashed line. The purple squares represent a high‐stability, cryogenic Si optical reference cavity.…”

Section: Stability and Accuracy In Optical Frequency Synthesismentioning

confidence: 99%

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Optical and Microwave Metrology at the 10⁻¹⁸ Level with an Er/Yb:glass Frequency Comb

Nardelli

Leopardi

Schibli

et al. 2023

Laser & Photonics Reviews

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Optical frequency combs are essential tools for precision metrology experiments ranging in application from remote spectroscopic sensing of trace gases to the characterization and comparison of optical atomic clocks for precision time‐keeping and searches for physics beyond the standard model. Presented here is a description of the architecture and a full characterization of a telecom‐band, self‐modelocking frequency comb based on a free‐space laser with an Er/Yb co‐doped glass gain medium. The laser provides a robust and cost‐effective alternative to Er:fibre laser based frequency combs, while offering stability and noise performance similar to Ti:sapphire laser systems. Finally, the utility of the Er/Yb:glass frequency comb is demonstrated in high‐stability frequency synthesis using two ultra‐stable optical references at 1157 nm and 1070 nm and in low‐noise photonic microwave generation by dividing these references to the microwave domain.

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“…Currently, the highest precision of optical clocks is below 10 −18 [6][7][8][9]. To evaluate the performance of optical clocks in experiments, a common approach is to compare two independent clocks to assess their stability, repeatability, and system uncertainty [9][10][11][12][13][14][15]. Such comparisons were made with the same or different types of atoms or ions.…”

Section: Introductionmentioning

confidence: 99%

Epidemiology of Diabetes in adults in GanSu province of northwest China

Zhang

Liu

Guo

2020

Preprint

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Objective:The purpose of this study was to study the characteristics and distribution of adult diabetes and prediabetes in Gansu province, northwest China.Methods : Using a stratified, cluster and random sampling design, we conducted a population-based, cross-sectional survey in GanSu province of northwest China. A representative sample of 31417 adults, aged 20-74 years, from 14 regions participated in the study. After an overnight fast, a 2-hour oral glucose tolerance test (OGTT) 75 g glucose load was conducted among participants without a self-reported history of diagnosed diabetes. Questionnaire survey, physical examination and serum lipid level were also conducted in the study. The Epidata version 3.1 and SPSS version 21.0 were used for data inputting and statistics analyzing. Results: The rough prevalence of diabetes in adults in Gansu province of northwest China was 10.6% (12.3% among men and 9.2% among women) and the age-standardized prevalence of diabetes is 9.0%. The prevalence of diagnosed and emerging diabetes was 5.2% and 5.4%, respectively. The prevalence of diabetes among Han, Hui, Tibetan, Yugur, Dongxiang nationality and the Baoan nationality were 10.7%, 11.3%, 5.5%, 7.7%, 8.9% and 7.9% respectively. In addition, the prevalence of prediabetes was estimated to be 15.2% (15.7% among men and 14.7% among women). The prevalence of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were 3.5% and 11.6% respectively. The prevalence of diabetes and prediabetes increased with increasing age and body mass index (BMI). The prevalence of diabetes among urban residents was higher than that among rural residents (11.5% vs. 9.5%) which is different from prediabetes (14.2% vs. 16.3%). Binary logistic regression analysis showed that age, male sex, urban residents, smoking, family history of diabetes, abdominal obesity, overweight, generalized obesity, hypertension, dyslipidemia, low levels of education, and high level of economic development were significantly associated with diabetes. Simultaneously, age, male sex, rural residents, drinking, abdominal obesity, overweight, general obesity, hypertension and low levels of education were significantly associated with prediabetes. Conclusions: The epidemic situation of diabetes in northwest China's Gansu province is serious. The distribution of diabetes between different sex, age groups and different ethnic groups were significantly different. More than half of the diabetes patients are undiagnosed, which showed the low hospitalizing rate and the lack of public awareness of diabetes.

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Improved interspecies optical clock comparisons through differential spectroscopy

Cited by 14 publications

References 32 publications

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Optical and Microwave Metrology at the 10⁻¹⁸ Level with an Er/Yb:glass Frequency Comb

Epidemiology of Diabetes in adults in GanSu province of northwest China

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Improved interspecies optical clock comparisons through differential spectroscopy

Cited by 14 publications

References 32 publications

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Mid-circuit correction of correlated phase errors using an array of spectator qubits

Optical and Microwave Metrology at the 10−18 Level with an Er/Yb:glass Frequency Comb

Epidemiology of Diabetes in adults in GanSu province of northwest China

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Optical and Microwave Metrology at the 10⁻¹⁸ Level with an Er/Yb:glass Frequency Comb