Jacobsenweinreich4317

Controlling matter-light interactions with cavities is of fundamental importance in modern science and technology1. This is exemplified in the strong-coupling regime, where matter-light hybrid modes form, with properties that are controllable by optical-wavelength photons2,3. By contrast, matter excitations on the nanometre scale are harder to access. In two-dimensional van der Waals heterostructures, a tunable moiré lattice potential for electronic excitations may form4, enabling the generation of correlated electron gases in the lattice potentials5-9. Excitons confined in moiré lattices have also been reported10,11, but no cooperative effects have been observed and interactions with light have remained perturbative12-15. Here, by integrating MoSe2-WS2 heterobilayers in a microcavity, we establish cooperative coupling between moiré-lattice excitons and microcavity photons up to the temperature of liquid nitrogen, thereby integrating versatile control of both matter and light into one platform. learn more The density dependence of the moiré polaritons reveals strong nonlinearity due to exciton blockade, suppressed exciton energy shift and suppressed excitation-induced dephasing, all of which are consistent with the quantum confined nature of the moiré excitons. link2 Such a moiré polariton system combines strong nonlinearity and microscopic-scale tuning of matter excitations using cavity engineering and long-range light coherence, providing a platform with which to study collective phenomena from tunable arrays of quantum emitters.Lead halide perovskites are promising semiconductors for light-emitting applications because they exhibit bright, bandgap-tunable luminescence with high colour purity1,2. Photoluminescence quantum yields close to unity have been achieved for perovskite nanocrystals across a broad range of emission colours, and light-emitting diodes with external quantum efficiencies exceeding 20 per cent-approaching those of commercial organic light-emitting diodes-have been demonstrated in both the infrared and the green emission channels1,3,4. However, owing to the formation of lower-bandgap iodide-rich domains, efficient and colour-stable red electroluminescence from mixed-halide perovskites has not yet been realized5,6. Here we report the treatment of mixed-halide perovskite nanocrystals with multidentate ligands to suppress halide segregation under electroluminescent operation. We demonstrate colour-stable, red emission centred at 620 nanometres, with an electroluminescence external quantum efficiency of 20.3 per cent. We show that a key function of the ligand treatment is to 'clean' the nanocrystal surface through the removal of lead atoms. Density functional theory calculations reveal that the binding between the ligands and the nanocrystal surface suppresses the formation of iodine Frenkel defects, which in turn inhibits halide segregation. Our work exemplifies how the functionality of metal halide perovskites is extremely sensitive to the nature of the (nano)crystalline surface and presents a route through which to control the formation and migration of surface defects. This is critical to achieve bandgap stability for light emission and could also have a broader impact on other optoelectronic applications-such as photovoltaics-for which bandgap stability is required.The deep sea remains the largest unknown territory on Earth because it is so difficult to explore1-4. Owing to the extremely high pressure in the deep sea, rigid vessels5-7 and pressure-compensation systems8-10 are typically required to protect mechatronic systems. However, deep-sea creatures that lack bulky or heavy pressure-tolerant systems can thrive at extreme depths11-17. Here, inspired by the structure of a deep-sea snailfish15, we develop an untethered soft robot for deep-sea exploration, with onboard power, control and actuation protected from pressure by integrating electronics in a silicone matrix. This self-powered robot eliminates the requirement for any rigid vessel. To reduce shear stress at the interfaces between electronic components, we decentralize the electronics by increasing the distance between components or separating them from the printed circuit board. Careful design of the dielectric elastomer material used for the robot's flapping fins allowed the robot to be actuated successfully in a field test in the Mariana Trench down to a depth of 10,900 metres and to swim freely in the South China Sea at a depth of 3,224 metres. We validate the pressure resilience of the electronic components and soft actuators through systematic experiments and theoretical analyses. Our work highlights the potential of designing soft, lightweight devices for use in extreme conditions.Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms1,2. Present-day photonic quantum computers3-7 have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware-software system for executing many-photon quantum circuit operations using integrated nanophotonics a programmable chip, operating at room temperature and interfaced with a fully automated control system. The system enables remote users to execute quantum algorithms that require up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and photon number-resolving readout on all outputs. Detection of multi-photon events with photon numbers and rates exceeding any previous programmable quantum optical demonstration is made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms Gaussian boson sampling, molecular vibronic spectra and graph similarity8. These demonstrations validate the platform as a launchpad for scaling photonic technologies for quantum information processing.Two-dimensional (2D) semiconductors have attracted tremendous interest as atomically thin channels that could facilitate continued transistor scaling. However, despite many proof-of-concept demonstrations, the full potential of 2D transistors has yet to be determined. To this end, the fundamental merits and technological limits of 2D transistors need a critical assessment and objective projection. Here we review the promise and current status of 2D transistors, and emphasize that widely used device parameters (such as carrier mobility and contact resistance) could be frequently misestimated or misinterpreted, and may not be the most reliable performance metrics for benchmarking 2D transistors. We suggest that the saturation or on-state current density, especially in the short-channel limit, could provide a more reliable measure for assessing the potential of diverse 2D semiconductors, and should be applied for cross-checking different studies, especially when milestone performance metrics are claimed. We also summarize the key technical challenges in optimizing the channels, contacts, dielectrics and substrates and outline potential pathways to push the performance limit of 2D transistors. We conclude with an overview of the critical technical targets, the key technological obstacles to the 'lab-to-fab' transition and the potential opportunities arising from the use of these atomically thin semiconductors.Clay minerals and pedogenic metal (oxyhydr)oxides are the most reactive soil mineral constituents controlling the long-term persistence of organic carbon (OC) in terrestrial ecosystems. However, their co-occurrence in most soils complicates direct assessment of their individual contribution to OC persistence. Making use of unique mineralogical combinations in soils located in the East Usambara Mountains of Tanzania, we disentangled the contribution of clay-sized aluminous minerals (kaolinite, gibbsite) and pedogenic Fe (oxyhydr)oxides (predominant goethite and hematite) on OC storage and stabilization under natural forests and croplands. Topsoil samples, varying in contents but not types of aluminous clays and pedogenic Fe (oxyhydr)oxides, were identified by selective extractions, X-ray diffraction, and Mössbauer spectroscopy. Associated abundance of particulate and mineral-associated organic matter (OM) was quantified by density fractionation and their changes during land-use conversion were determined as a measure of OC persistence. Additionally, we assessed the resistance of OC to chemical oxidation as well as microbial decomposition in a 50-day laboratory incubation. We found that the ratio of pedogenic Fe to aluminous clay is more consequential for OC storage and stabilization than their individual contents, despite the fact that Fe (oxyhydr)oxides generally exert a stronger impact on OC than aluminous clays. Conjunction of large amounts of Fe (oxyhydr)oxides with low aluminous clay contents caused the strongest accumulation of mineral-associated OC, a low soil respiration, high OC stability against chemical oxidation, and high OC persistence during land-use change. Our study suggests that certain mineralogical combinations in the humid tropics alleviate OM losses during land conversion because of the strong and selective mineral control on OC stabilization, particular if the weight ratio of pedogenic Fe to aluminous clay exceeds the threshold range of 0.44‒0.56.

Obesity is subject to strong family clustering. The relatives of participants in weight-loss interventions may also modify their lifestyle and lose weight. The aim of this study was to examine the presence and magnitude of a halo effect in untreated family members of participants enrolled in a randomized, multi-component, lifestyle intervention.

A total of 148 untreated adult family members of participants in an intensive weight-loss lifestyle intervention (the PREDIMED-Plus study) were included. Changes at 1 and 2 years in body weight, physical activity, and adherence to a traditional Mediterranean diet (MedDiet) were measured. Generalized linear mixed models were used to assess whether the change differed between family members of the intervention group compared to the control.

Untreated family members from the intervention group displayed a greater weight loss than those from the control after 1 and 2 years adjusted 2-year weight change difference between groups was -3.98 (SE 1.10) kg (p < 0.001).al activity weight-loss intervention, we found evidence of a halo effect in relatives on weight loss and improvement in adherence to a MedDiet, but not on physical activity. The expansion of MedDiet changes from individuals involved in a weight-loss intervention to their family members can be a facilitator for obesity prevention.

Whilst the consequences of weight bias and weight bias internalisation (WBI) have been explored, less is known about the factors contributing to their development. Some research has explored the role of social exposure in weight bias and WBI but has been limited in its definition of exposure and focused solely on western countries. link3 The present study therefore aimed to assess the role of social exposure defined in terms of both population and personal exposure in predicting weight bias and WBI, in an international sample.

Participants (N = 1041) from 33 countries, aged 18-85 years completed online measures of demographics, weight bias, WBI, and population and personal social exposure. Population exposure was defined using national obesity prevalence data from the World Health Organisation to classify countries as low (obesity rates ≤19.9%; n = 162), medium (20.0-29.9%; n = 672) or high prevalence (≥30%; n = 192). Personal exposure was defined in terms of personal contact and health and attractiveness normalisation.