Observation of superabsorption by correlated atoms

Emission and absorption of light lie at the heart of light-matter interaction. Although the emission and absorption rates are regarded as intrinsic properties of atoms and molecules, various ways to modify these rates have been sought in critical applications such as quantum information processing, metrology and light-energy harvesting. One of the promising approaches is to utilize collective behavior of emitters as in superradiance. Although superradiance has been observed in diverse systems, its conceptual counterpart in absorption has never been realized. Here, we demonstrate superabsorption, enhanced cooperative absorption, by correlated atoms of phase-matched superposition state. By implementing an opposite-phase-interference idea on a superradiant state or equivalently a time-reversal process of superradiance, we realized the superabsorption with its absorption rate much faster than that of the ordinary ground-state absorption. The number of photons completely absorbed for a given time interval was measured to be proportional to the square of the number of atoms. Our approach, breaking the limitation of the conventional absorption, can help weak-signal sensing and advance efficient light-energy harvesting as well as light-matter quantum interfaces.Comment: 7 pages, 5 figure

EXERCISE-INDUCED HORMONE, APELIN, IN MEDIATING FETAL MUSCLE AND ADIPOSE DEVELOPMENT

Obesity is a worsening problem and rapidly increasing in the U.S. and worldwide. Notably, accumulating studies have shown an inherent link between maternal obesity (MO) and metabolic dysfunction in children. Recently, several studies demonstrated that maternal exercise (ME) enhances the capacity of offspring to maintain metabolic homeostasis, which might protect metabolic disorders in the offspring due to MO. The underlying mechanisms, on the other hand, remain to be defined. The placenta is the key tissue mediating nutrients and oxygen delivery to fetuses and its development during pregnancy is impeded due to MO. We hypothesized that ME improves maternal metabolic health and prevents fetal overgrowth induced by maternal high fat diet (HFD)-induced obesity. First, we discovered that placental vascularization/angiogenesis and nutrient transport activities were impaired by MO, which was protected by exercise during pregnancy. Interestingly, in the placenta, a hormone, apelin, known to stimulate angiogenesis, was highly activated in response to exercise, but down-regulated by MO. Consistently, circulating apelin levels in both mothers and fetuses were elevated due to ME. To further explore roles of apelin, we studied whether ME stimulates brown and beige adipose tissue development and enhances their thermogenic activity in the offspring, showing that maternal administration of apelin mimicked the beneficial effects of exercise on offspring metabolic health through stimulating brown/beige adipogenesis, which could suggest a novel therapeutic approach for protecting programming effect of maternal inactivity on offspring obesity. Besides, since brown fat and muscle are major tissues responsible for metabolic homeostasis, we additionally studied the effect of ME on fetal and offspring muscle development, showing that ME enhanced mitochondrial biogenesis in fetal and offspring skeletal muscle, which enhances exercise endurance capacity and metabolic health of the offspring muscle. In summary, exercise-induced apelin is a feasible target to promote brown fat and muscle development, which positively affects not only mothers themselves, but their offspring

Realization of superabsorption by time reversal of superradiance

Emission and absorption of light lie at the heart of light–matter interaction1. Although emission and absorption rates are regarded as intrinsic properties of atoms and molecules, various ways to modify these rates have been sought in applications such as quantum information processing2, metrology3 and light-energy harvesting4. One promising approach is to utilize collective behaviour of emitters in the same way as in superradiance5. Although superradiance has been observed in diverse systems3,6–10, its conceptual counterpart in absorption has never been realized11 until now. Here we demonstrate enhanced cooperative absorption—superabsorption—by implementing a time-reversal process of superradiance. The observed superabsorption rate is much higher than that of ordinary absorption, with the number of absorbed photons scaling with the square of the number of atoms, exhibiting the cooperative nature of superabsorption. The present superabsorption—which performs beyond the limitations of conventional absorption—can facilitate weak-signal sensing1, light-energy harvesting11 and light–matter quantum interfaces2. © 2021, The Author(s), under exclusive licence to Springer Nature Limited.11Nsciescopu

Growth and development of pure Li2MoO4 crystals for rare event experiment at CUP

© 2020 IOP Publishing Ltd and Sissa Medialab. The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0 nu beta beta) of Mo-100 in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0 nu beta beta signal. For the last few years, we have been growing and studying Li2MoO4 crystals in a clean-environment facility to minimize external contamination during the crystal growth. Before growing (Li2MoO4)-Mo-100 crystal, we have studied (Li2MoO4)-Mo-nat crystal growth by a conventional Czochralski (CZ) grower. We grew a few different kinds of Li(2)(nat)MO(4)crystals using different raw materials in a campaign to minimize impurities. We prepared the fused Al2O3 refractories for the growth of ingots. Purities of the grown crystals were measured with high purity germanium detectors and by inductively coupled plasma mass spectrometry. The results show that the Li2MoO4 crystal has purity levels suitable for rare-event experiments. In this study, we present the growth of Li2MoO4 crystals at CUP and their purities11sci

Three-Dimensional Quantitative Assessment of Pedicle Screw Accuracy in Clinical Utilization of a New Robotic System in Spine Surgery: A Multicenter Study

Objective The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery. Methods A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS). Results A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications. Conclusion Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches