ABSTRACT
Superposition, entanglement and non-locality constitute fundamental features of quantum physics. The fact that quantum physics does not follow the principle of local causality1-3 can be experimentally demonstrated in Bell tests4 performed on pairs of spatially separated, entangled quantum systems. Although Bell tests, which are widely regarded as a litmus test of quantum physics, have been explored using a broad range of quantum systems over the past 50 years, only relatively recently have experiments free of so-called loopholes5 succeeded. Such experiments have been performed with spins in nitrogen-vacancy centres6, optical photons7-9 and neutral atoms10. Here we demonstrate a loophole-free violation of Bell's inequality with superconducting circuits, which are a prime contender for realizing quantum computing technology11. To evaluate a Clauser-Horne-Shimony-Holt-type Bell inequality4, we deterministically entangle a pair of qubits12 and perform fast and high-fidelity measurements13 along randomly chosen bases on the qubits connected through a cryogenic link14 spanning a distance of 30 metres. Evaluating more than 1 million experimental trials, we find an average S value of 2.0747 ± 0.0033, violating Bell's inequality with a P value smaller than 10-108. Our work demonstrates that non-locality is a viable new resource in quantum information technology realized with superconducting circuits with potential applications in quantum communication, quantum computing and fundamental physics15.
ABSTRACT
OBJECTIVE: To examine whether the relationship between obesity and asthma in young girls and boys can be explained by social and physical characteristics of the home environment. STUDY DESIGN: We examined the relationship between asthma and obesity in children in the Fragile Families and Child Wellbeing Study (n=1815). Asthma was determined through maternal report of asthma diagnosis by a doctor (active in past 12 months). Weight and height of child was measured during an in-home visit. Data on home social (maternal depression, intimate partner violence) and physical environmental factors (housing quality, tobacco exposure) were collected via questionnaire. RESULTS: Ten percent of children had active asthma, 19% of children were overweight, and 17% of children were obese. In fully adjusted models, obese children had twice the odds of having asthma (OR, 2.3; 95% CI, 1.5-3.3) compared with children of normal body weight. In stratified analyses, overweight boys, but not overweight girls, had increased of odds of asthma. Obese boys and girls had increased odds of asthma compared with boys and girls of normal body weight. CONCLUSION: The relationship between asthma and obesity is present in boys and girls as young as 3 years of age; a relationship between being overweight and asthma is only present among boys. This relationship is not attributable to shared social and environmental factors of the children's home.
