Optical observation of single spins in silicon.

The global quantum internet will require long-lived, telecommunications-band photon-matter interfaces manufactured at scale1. Preliminary quantum networks based on photon-matter interfaces that meet a subset of these demands are encouraging efforts to identify new high-performance alternatives2. Silicon is an ideal host for commercial-scale solid-state quantum technologies. It is already an advanced platform within the global integrated photonics and microelectronics industries, as well as host to record-setting long-lived spin qubits3. Despite the overwhelming potential of the silicon quantum platform, the optical detection of individually addressable photon-spin interfaces in silicon has remained elusive. In this work, we integrate individually addressable 'T centre' photon-spin qubits in silicon photonic structures and characterize their spin-dependent telecommunications-band optical transitions. These results unlock immediate opportunities to construct silicon-integrated, telecommunications-band quantum information networks.

The Emotional Eating Scale Adapted for Children and Adolescents (EES-C): development and preliminary validation of a short-form.

The 25-item Emotional Eating Scale for children and adolescents (EES-C) is a psychometrically sound instrument that measures the extent to which youth eat in response to negative emotions. Nonetheless, questionnaire length may serve as a barrier to routine administration in clinical and school settings, and diminish the likelihood of the measure being utilized in population-wide health studies. The present study reported on the development and preliminary validation of a short-form of EES-C using data from two previously published studies. Guidelines for the development of short-form questionnaires, content and factor analyses, and other indices including standard deviations, item-total correlations, inter-item correlations, Cronbach's alpha without the item, and floor/ceiling effects were examined to develop a 10-item EES-C Short-Form. The EES-C Short-Form demonstrated acceptable psychometric properties, including good internal consistency reliability (alpha = .87) and a high degree of overlapping variance with the original EES-C Total Score and Subscale Scores (r = .71 to .96). The EES-C Short-Form also manifested a unidimensional factor structure in an Exploratory Factor Analysis, supporting construct validity. Taken together, results from the current study provide preliminary evidence of the reliability and validity of a 10-item EES-C Short-Form.

Acculturative stress and emotional eating in Latino adolescents.

PURPOSE: Despite data that suggest Latino adolescents experience acculturative stress (i.e., feeling overwhelmed by conflicting cultural practices, language problems, and ethnic self-consciousness) and endorse elevated levels of emotional eating, there has been an absence of research examining the relations between acculturative stress and emotional eating in this population. The purpose of the present study was to (1) examine the associations between acculturative stress, emotional eating, and change in BMIz scores in Latino adolescents over a 3-month period, and (2) compare Latino and non-Latino adolescents on measures of acculturative stress, emotional eating, and body mass index (BMI). METHODS: The sample comprised 168 Latino (mean age 13.69 years; SD 0.88) and 278 non-Latino (mean age 13.68 years; SD 0.79) middle and high school students. Participants completed the Emotional Eating Scale for Children and Adolescents (EES-C), the Social, Attitudinal, Familial, and Environmental Acculturative Stress Scale for Children (SAFE-C), and a demographic questionnaire. Participants had their height and weight measured after completing the questionnaires and at a second-time point, approximately 3 months after time 1 measurements. Independent samples t tests and Cohen's d effect sizes were used to investigate whether there were differences between Latino adolescents and non-Latino adolescents. Pearson correlations were computed to examine associations between acculturative stress, emotional eating, and change in BMIz scores in the Latino sample. RESULTS: Latino adolescents endorsed significantly higher acculturative stress on the SAFE-C compared to non-Latino adolescents (Latino mean 30.81; non-Latino mean 25.64; p < 0.001; Cohen's d effect size = 0.35). In the Latino sample, acculturative stress was associated with higher levels of emotional eating. Latino and non-Latino adolescents endorsed similar levels of emotional eating. CONCLUSIONS: The present findings provide preliminary evidence that acculturative stress may serve as a risk factor for emotional eating among Latino adolescents. Future obesity prevention and intervention programs developed for Latino adolescents may benefit from addressing acculturative stress, particularly among more recent Latino immigrants. LEVEL OF EVIDENCE: Level 3, case-control analytic study.

Tentacle Musculature in the Cubozoan Jellyfish Carybdea marsupialis.

The diploblastic cnidarian body plan comprising the epidermis and gastrodermis has remained largely unchanged since it evolved roughly 600 Ma. The origin of muscle from the mesoderm in triploblastic lineages is a central evolutionary question in higher animals. Triploblasts have three embryonic germ layers: the endoderm, mesoderm, and ectoderm, which develop into organs, muscle, and skin, respectively. Diploblasts lack the mesoderm, the layer thought to give rise to the skeletomuscular system. However, phyla such as Cnidaria and Ctenophora, which are typically classified as diploblasts, possess striated musculature. Within phylum Cnidaria, class Cubozoa includes carnivorous box jellyfish, which are capable of extending and contracting their tentacles for predation and defense mechanisms, thus suggesting a well-organized system of muscles. Here, the tentacle musculature of the cubomedusae Carybdea marsupialis is investigated using transmission electron microscopy in conjunction with light microscopy to further understand the arrangement of musculature in these primitive animals. Cross sections of tentacles confirmed that the gastrodermis is separated from the epidermis by a collagenous mesogleal layer containing numerous longitudinal muscle cells arranged in fascicles. Longitudinal muscles permit the tentacle to retract toward the bell during fast tentacle shortening and crumpling behavioral responses. Circular muscle cells were found in the gastrodermis and epidermis, encircling the layer of longitudinal muscle. These circular muscles likely enable the elongation process that allows the tentacles to return to a resting state after contraction. The presence of a definitive muscle cell layer within the mesoglea suggests that C. marsupialis has an advanced muscle morphology that is similar to triploblastic animals.

A photonic platform for donor spin qubits in silicon.

Donor spins in silicon are highly competitive qubits for upcoming quantum technologies, offering complementary metal-oxide semiconductor compatibility, coherence (T2) times of minutes to hours, and simultaneous initialization, manipulation, and readout fidelities near ~99.9%. This allows for many quantum error correction protocols, which will be essential for scale-up. However, a proven method of reliably coupling spatially separated donor qubits has yet to be identified. We present a scalable silicon-based platform using the unique optical properties of "deep" chalcogen donors. For the prototypical 77Se+ donor, we measure lower bounds on the transition dipole moment and excited-state lifetime, enabling access to the strong coupling limit of cavity quantum electrodynamics using known silicon photonic resonator technology and integrated silicon photonics. We also report relatively strong photon emission from this same transition. These results unlock clear pathways for silicon-based quantum computing, spin-to-photon conversion, photonic memories, integrated single-photon sources, and all-optical switches.

A dressed spin qubit in silicon.

Coherent dressing of a quantum two-level system provides access to a new quantum system with improved properties-a different and easily tunable level splitting, faster control and longer coherence times. In our work we investigate the properties of the dressed, donor-bound electron spin in silicon, and assess its potential as a quantum bit in scalable architectures. The two dressed spin-polariton levels constitute a quantum bit that can be coherently driven with an oscillating magnetic field, an oscillating electric field, frequency modulation of the driving field or a simple detuning pulse. We measure coherence times of and , one order of magnitude longer than those of the undressed spin. Furthermore, the use of the dressed states enables coherent coupling of the solid-state spins to electric fields and mechanical oscillations.

Vibration-induced electrical noise in a cryogen-free dilution refrigerator: Characterization, mitigation, and impact on qubit coherence.

Cryogen-free low-temperature setups are becoming more prominent in experimental science due to their convenience and reliability, and concern about the increasing scarcity of helium as a natural resource. Despite not having any moving parts at the cold end, pulse tube cryocoolers introduce vibrations that can be detrimental to the experiments. We characterize the coupling of these vibrations to the electrical signal observed on cables installed in a cryogen-free dilution refrigerator. The dominant electrical noise is in the 5-10 kHz range and its magnitude is found to be strongly temperature dependent. We test the performance of different cables designed to diagnose and tackle the noise, and find triboelectrics to be the dominant mechanism coupling the vibrations to the electrical signal. Flattening a semi-rigid cable or jacketing a flexible cable in order to restrict movement within the cable, successfully reduces the noise level by over an order of magnitude. Furthermore, we characterize the effect of the pulse tube vibrations on an electron spin qubit device in this setup. Coherence measurements are used to map out the spectrum of the noise experienced by the qubit, revealing spectral components matching the spectral signature of the pulse tube.

Bell's inequality violation with spins in silicon.

Bell's theorem proves the existence of entangled quantum states with no classical counterpart. An experimental violation of Bell's inequality demands simultaneously high fidelities in the preparation, manipulation and measurement of multipartite quantum entangled states, and provides a single-number benchmark for the performance of devices that use such states for quantum computing. We demonstrate a Bell/ Clauser-Horne-Shimony-Holt inequality violation with Bell signals up to 2.70(9), using the electron and the nuclear spins of a single phosphorus atom embedded in a silicon nanoelectronic device. Two-qubit state tomography reveals that our prepared states match the target maximally entangled Bell states with >96% fidelity. These experiments demonstrate complete control of the two-qubit Hilbert space of a phosphorus atom and highlight the important function of the nuclear qubit to expand the computational basis and maximize the readout fidelity.

Room-temperature quantum bit storage exceeding 39 minutes using ionized donors in silicon-28.

Quantum memories capable of storing and retrieving coherent information for extended times at room temperature would enable a host of new technologies. Electron and nuclear spin qubits using shallow neutral donors in semiconductors have been studied extensively but are limited to low temperatures (≲10 kelvin); however, the nuclear spins of ionized donors have the potential for high-temperature operation. We used optical methods and dynamical decoupling to realize this potential for an ensemble of phosphorous-31 donors in isotopically purified silicon-28 and observed a room-temperature coherence time of over 39 minutes. We further showed that a coherent spin superposition can be cycled from 4.2 kelvin to room temperature and back, and we report a cryogenic coherence time of 3 hours in the same system.

Probing the C60 triplet state coupling to nuclear spins inside and out.

The photoexcitation of functionalized fullerenes to their paramagnetic triplet electronic state can be studied by pulsed electron paramagnetic resonance (EPR) spectroscopy, whereas the interactions of this state with the surrounding nuclear spins can be observed by a related technique: electron nuclear double resonance (ENDOR). In this study, we present EPR and ENDOR studies on a functionalized exohedral fullerene system, dimethyl[9-hydro (C60-Ih)[5,6]fulleren-1(9H)-yl]phosphonate (DMHFP), where the triplet electron spin has been used to hyperpolarize, couple and measure two nuclear spins. We go on to discuss the extension of these methods to study a new class of endohedral fullerenes filled with small molecules, such as H2@C60, and we relate the results to density functional calculations.

Controlling and exploiting phases in multi-spin systems using electron spin resonance and nuclear magnetic resonance.

The phase of a superposition state is a quintessential characteristic that differentiates a quantum bit of information from a classical one. This phase can be manipulated dynamically or geometrically, and can be exploited to sensitively estimate Hamiltonian parameters, perform faithful quantum state tomography and encode quantum information into multiple modes of an ensemble. Here we discuss the methods that we have employed to manipulate and exploit the phase information of single-, two-, multi-qubit and multi-mode spin systems.

Violation of a Leggett-Garg inequality with ideal non-invasive measurements.

The quantum superposition principle states that an entity can exist in two different states simultaneously, counter to our 'classical' intuition. Is it possible to understand a given system's behaviour without such a concept? A test designed by Leggett and Garg can rule out this possibility. The test, originally intended for macroscopic objects, has been implemented in various systems. However to date no experiment has employed the 'ideal negative result' measurements that are required for the most robust test. Here we introduce a general protocol for these special measurements using an ancillary system, which acts as a local measuring device but which need not be perfectly prepared. We report an experimental realization using spin-bearing phosphorus impurities in silicon. The results demonstrate the necessity of a non-classical picture for this class of microscopic system. Our procedure can be applied to systems of any size, whether individually controlled or in a spatial ensemble.

Entanglement in a solid-state spin ensemble.

Entanglement is the quintessential quantum phenomenon. It is a necessary ingredient in most emerging quantum technologies, including quantum repeaters, quantum information processing and the strongest forms of quantum cryptography. Spin ensembles, such as those used in liquid-state nuclear magnetic resonance, have been important for the development of quantum control methods. However, these demonstrations contain no entanglement and ultimately constitute classical simulations of quantum algorithms. Here we report the on-demand generation of entanglement between an ensemble of electron and nuclear spins in isotopically engineered, phosphorus-doped silicon. We combined high-field (3.4 T), low-temperature (2.9 K) electron spin resonance with hyperpolarization of the (31)P nuclear spin to obtain an initial state of sufficient purity to create a non-classical, inseparable state. The state was verified using density matrix tomography based on geometric phase gates, and had a fidelity of 98% relative to the ideal state at this field and temperature. The entanglement operation was performed simultaneously, with high fidelity, on 10(10) spin pairs; this fulfils one of the essential requirements for a silicon-based quantum information processor.

Education and vulnerability: the role of schools in protecting young women and girls from HIV in southern Africa.

Education has a potentially important role to play in tackling the spread of HIV, but is there evidence that this potential is realized? This analysis combines the results of previous literature reviews and updates them with the findings of recent randomized controlled trials and a discussion of possible mechanisms for the effect of schooling on vulnerability to HIV infection. There is a growing body of evidence that keeping girls in school reduces their risk of contracting HIV. The relationship between educational attainment and HIV has changed over time, with educational attainment now more likely to be associated with a lower risk of HIV infection than earlier in the epidemic. Educational attainment cannot, however, be isolated from other socioeconomic factors as the cause of HIV risk reduction. The findings of this analysis suggest that the equitable expansion of primary and secondary schooling for girls in southern Africa will help reduce their vulnerability to HIV. Evidence of ineffective HIV prevention education in schools underlines the need for careful evidence-based programme design. Despite the challenges, recent provisional evidence suggests that highly targeted programmes promoting realistic options for young adults may lead to safer sexual behaviour. Targeted education programmes have also been successful in changing students' attitudes to people living with HIV and AIDS, which is associated with testing and treatment decisions. This reduction in stigma may be crucial in encouraging the uptake of voluntary counselling and testing, a central strategy in the control of the epidemic. Expansions of carefully designed and evaluated school-based HIV prevention programmes can help to reduce stigma and have the potential to promote safe sexual behaviour.

Prostaglandin E2 gel versus misoprostol for cervical ripening in patients with premature rupture of membranes after 34 weeks.

OBJECTIVE: To compare intravaginal misoprostol to prostaglandin (PG) E2 for cervical ripening in women with premature rupture of the membranes (PROM) after 34 weeks of gestation. METHODS: Women with PROM after 34 weeks of gestation and an unripe cervix were randomized to receive PGE2 (2.5 mg) or misoprostol (50 microg). Both agents were placed intravaginally immediately after randomization, and the dose was repeated 6 hours later if necessary. After another 6 hours from the second insertion, oxytocin treatment was started if labor had not begun. Forty patients in each group were required to show a 30% improvement in delivery within 12 hours in the misoprostol group. RESULTS: One hundred nine patients were randomized; 54 were assigned to misoprostol and 55 to PGE2. Important demographic and clinical characteristics were similar between the groups. The mean time from first insertion to delivery was 16.4 hours in the misoprostol group and 22.0 hours in the PGE2 group. A second dose was required less frequently in the misoprostol group (22% vs 62% in the PGE2 group), and the percentage of patients delivered within 12 hours was higher in the misoprostol group (41% vs 16%). Tachysystole occurred in 20% and 6% of women in the misoprostol and PGE2 groups, respectively. Hyperstimulation occurred in 9% and 0%, and cesarean delivery in 19% and 26% of women in the misoprostol and PGE2 groups, respectively. Neonatal outcome was similar between groups. CONCLUSION: Intravaginal misoprostol is more effective than local PGE2 application to treat PROM after 34 weeks of gestation, but tachysystole occurs more commonly with misoprostol.