Time-resolved magnetic sensing with electronic spins in diamond

Quantum probes can measure time-varying fields with high sensitivity and spatial resolution, enabling the study of biological, material, and physical phenomena at the nanometer scale. In particular, nitrogen-vacancy centers in diamond have recently emerged as promising sensors of magnetic and electric fields. Although coherent control techniques have measured the amplitude of constant or oscillating fields, these techniques are not suitable for measuring time-varying fields with unknown dynamics. Here we introduce a coherent acquisition method to accurately reconstruct the temporal profile of time-varying fields using Walsh sequences. These decoupling sequences act as digital filters that efficiently extract spectral coefficients while suppressing decoherence, thus providing improved sensitivity over existing strategies. We experimentally reconstruct the magnetic field radiated by a physical model of a neuron using a single electronic spin in diamond and discuss practical applications. These results will be useful to implement time-resolved magnetic sensing with quantum probes at the nanometer scale.Comment: 8+12 page

2000-times repeated imaging of strontium atoms in clock-magic tweezer arrays

We demonstrate single-atom resolved imaging with a survival probability of $0.99932(8)$ and a fidelity of $0.99991(1)$, enabling us to perform repeated high-fidelity imaging of single atoms in tweezers for thousands of times. We further observe lifetimes under laser cooling of more than seven minutes, an order of magnitude longer than in previous tweezer studies. Experiments are performed with strontium atoms in $813.4~\text{nm}$ tweezer arrays, which is at a magic wavelength for the clock transition. Tuning to this wavelength is enabled by off-magic Sisyphus cooling on the intercombination line, which lets us choose the tweezer wavelength almost arbitrarily. We find that a single not retro-reflected cooling beam in the radial direction is sufficient for mitigating recoil heating during imaging. Moreover, this cooling technique yields temperatures below $5~\mu$K, as measured by release and recapture. Finally, we demonstrate clock-state resolved detection with average survival probability of $0.996(1)$ and average state detection fidelity of $0.981(1)$. Our work paves the way for atom-by-atom assembly of large defect-free arrays of alkaline-earth atoms, in which repeated interrogation of the clock transition is an imminent possibility.Comment: 6 pages, 5 figures, 1 vide

Product longevity and shared ownership: Sustainable routes to satisfying the world’s growing demand for goods 

It has been estimated that by 2030 the number of people who are wealthy enough to be significant consumers will have tripled. This will have a dramatic impact on the demands for primary materials and energy. It has been estimated that with improvements in design and manufacturing it is possible to maintain the current level of production using 70% of the current primary material consumed. Even with these improvements on the production side, there will still be a doubling of primary material requirements by the end of the century, with accompanying rises in industrial energy demand, if the rise in demand for goods and services is to be met. It is therefore clear that the consumption of products must also be explored. Product longevity and using goods more intensively are two strategies which could reduce the demand for new goods. If products last longer, then manufacturing output can concentrate on emerging markets rather than the market for replacement goods. There are many goods which are infrequently used, these seldom wear out. The total demand for such could be drastically reduced if they we re shared with other people. Sharing of goods has traditionally been conducted between friends or by hiring equipment, but modern communication systems and social media could increase the opportunities to share goods. Sharing goods also increases access to a range of goods for those on low incomes. From a series of workshops it has been found that the principal challenges are sociological rather than technological. This paper contains a discussion of these challenges and explores possible futures where these two strategies have been adopted. In addition, the barriers and opportunities that these strategies offer for 548 AIMS Energy Volume 3, Issue 4, 547-561. consumers and businesses are identified, and areas where government policy could be instigated to bring about change are highlighted

Identification and Control of Electron-Nuclear Spin Defects in Diamond

We experimentally demonstrate an approach to scale up quantum devices by harnessing spin defects in the environment of a quantum probe. We follow this approach to identify, locate, and control two electron-nuclear spin defects in the environment of a single nitrogen-vacancy center in diamond. By performing spectroscopy at various orientations of the magnetic field, we extract the unknown parameters of the hyperfine and dipolar interaction tensors, which we use to locate the two spin defects and design control sequences to initialize, manipulate, and readout their quantum state. Finally, we create quantum coherence among the three electron spins, paving the way for the creation of genuine tripartite entanglement. This approach will be useful in assembling multispin quantum registers for applications in quantum sensing and quantum information processing

Alkaline earth atoms in optical tweezers

We demonstrate single-shot imaging and narrow-line cooling of individual alkaline earth atoms in optical tweezers; specifically, strontium-88 atoms trapped in $515.2~\text{nm}$ light. We achieve high-fidelity single-atom-resolved imaging by detecting photons from the broad singlet transition while cooling on the narrow intercombination line, and extend this technique to highly uniform two-dimensional arrays of $121$ tweezers. Cooling during imaging is based on a previously unobserved narrow-line Sisyphus mechanism, which we predict to be applicable in a wide variety of experimental situations. Further, we demonstrate optically resolved sideband cooling of a single atom close to the motional ground state of a tweezer. Precise determination of losses during imaging indicate that the branching ratio from $^1$P$_1$ to $^1$D$_2$ is more than a factor of two larger than commonly quoted, a discrepancy also predicted by our ab initio calculations. We also measure the differential polarizability of the intercombination line in a $515.2~\text{nm}$ tweezer and achieve a magic-trapping configuration by tuning the tweezer polarization from linear to elliptical. We present calculations, in agreement with our results, which predict a magic crossing for linear polarization at $520(2)~\text{nm}$ and a crossing independent of polarization at 500.65(50)nm. Our results pave the way for a wide range of novel experimental avenues based on individually controlled alkaline earth atoms in tweezers -- from fundamental experiments in atomic physics to quantum computing, simulation, and metrology implementations

Caries is Associated with Asthma and Epilepsy

OBJECTIVES: There is evidence of association between systemic diseases and oral conditions, although it is not clear if these are direct or mediated by underlying factors such as health behaviors. The aim of this work was to evaluate whether self-reported systemic diseases were associated with caries experience. METHODS: Medical history data and caries experience (DMFT and DMFS; Decayed, Missing due to caries, Filled Teeth/Surface) were obtained from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository. Information on 318 subjects (175 females and 143 males) was evaluated. Regression analysis was used to test for association between caries experience and disease status. RESULTS: The stronger associations were found between caries experience and asthma and epilepsy. With respect to asthma, DMFT above 15 (R(2) = 0.04) and DMFS above 50 (R(2) = 0.02) were associated. After controlling for gender differences in asthma, the associations remained strong (R(2) = 0.05 for both DMFT and DMFS). For epilepsy, DMFT above 15 (R(2) = 0.18) and DMFS above 50 (R(2) = 0.14) were associated. CONCLUSIONS: Asthma and epilepsy are associated with higher caries experience

High-Fidelity Control, Detection, and Entanglement of Alkaline-Earth Rydberg Atoms

Trapped neutral atoms have become a prominent platform for quantum science, where entanglement fidelity records have been set using highly excited Rydberg states. However, controlled two-qubit entanglement generation has so far been limited to alkali species, leaving the exploitation of more complex electronic structures as an open frontier that could lead to improved fidelities and fundamentally different applications such as quantum-enhanced optical clocks. Here, we demonstrate a novel approach utilizing the two-valence electron structure of individual alkaline-earth Rydberg atoms. We find fidelities for Rydberg state detection, single-atom Rabi operations and two-atom entanglement that surpass previously published values. Our results pave the way for novel applications, including programmable quantum metrology and hybrid atom–ion systems, and set the stage for alkaline-earth based quantum computing architectures

Identification and control of an environmental spin defect beyond the coherence limit of a central spin

Electronic spin defects in the environment of an optically-active spin can be used to increase the size and hence the performance of solid-state quantum registers, especially for applications in quantum metrology and quantum communication. Although multi-qubit electronic-spin registers have been realized using dark spins in the environment of a Nitrogen-Vacancy (NV) center in diamond, these registers have only included spins directly coupled to the NV, significantly restricting their maximum attainable size. To address this problem, we present a scalable approach to increase the size of electronic-spin registers. Our approach exploits a weakly-coupled probe spin together with double-resonance control sequences to mediate the transfer of spin polarization between the central NV spin and an environmental spin that is not directly coupled to it. We experimentally realize this approach to demonstrate the detection and coherent control of an unknown electronic spin outside the coherence limit of a central NV. Our work paves the way for engineering larger quantum spin registers, which have the potential to advance nanoscale sensing, enable correlated noise spectroscopy for error correction, and facilitate the realization of spin-chain quantum wires for quantum communication