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We discuss the possibility of self-hybridisation in high-index dielectric nanoparticles, where Mie modes of electric or magnetic type can couple to the interband transitions of the material, leading to spectral anticrossings. Starting with an idealised system described by moderately high constant permittivity with a narrow Lorentzian, in which self-hybridisation is visible for both plane-wave and electron-beam excitation, we embark on a quest for realistic systems where this effect should be visible. We explore a variety of spherical particles made of traditional semiconductors such as Si, GaAs, and GaP. With the effect hardly discernible, we identify two major causes hindering observation of self-hybridisation: the very broad spectral fingerprints of interband transitions in most candidate materials, and the significant overlap between electric and magnetic Mie modes in nanospheres. We thus depart from the spherical shape, and show that interband–Mie hybridisation is indeed feasible in the example of GaAs cylinders, even with a simple plane-wave source. This so-far unreported kind of polariton has to be considered when interpreting experimental spectra of Mie-resonant nanoparticles and assigning modal characters to specific features. On the other hand, it has the potential to be useful for the characterisation of the optical properties of dielectric materials, through control of the hybridisation strength via nanoparticle size and shape, and for applications that exploit Mie resonances in metamaterials, highly-directional antennas, or photovoltaics.

Impurity-vacancy centers in diamond offer a new class of robust photon sources with versatile quantum properties. While individual color centers commonly act as single-photon sources, their ensembles have been theoretically predicted to have tunable photon-emission statistics. Importantly, the particular type of excitation affects the emission properties of a color center ensemble within a diamond crystal. While optical excitation favors non-synchronized excitation of color centers within an ensemble, electron-beam excitation can synchronize the emitters excitation and thereby provides a control of the second-order correlation function g 2(0). In this letter, we demonstrate experimentally that the photon stream from an ensemble of color centers can exhibit g 2(0) both above and below unity, thereby confirming long standing theoretical predictions by Meuret et al. [S. Meuret, L. H. G. Tizei, T. Cazimajou, et al., “Photon bunching in cathodoluminescence,” Phys. Rev. Lett., vol. 114, no. 19, p. 197401, 2015.]. Such a photon source based on an ensemble of few color centers in a diamond crystal provides a highly tunable platform for informational technologies operating at room temperature.

Objective Since introduction of the programme in April 2021, COVID-19 vaccine uptake has been low at less than 20%. This study explored community members’ and health workers’ perspectives on the COVID-19 vaccine uptake and its influencing factors in Zambia.Study design A qualitative study employing focus group discussions (FGDs) and in-depth interviews (IDIs).Study setting Sixteen primary healthcare facilities selected from Lusaka, Copperbelt, Central and Southern provinces.Participants A total of 32 FGDs comprising local community members and 30 IDIs including health workers, traditional, religious and civic leaders (n=272). FGDs were separated based on age (youth and adults), sex (male and female) and place of residence (urban and rural).Results Both FGD and IDI participants agreed that vaccine uptake was low. Limited knowledge, access to information, myths and misconceptions, negative attitude, low-risk perception and supply in remote areas affected vaccine uptake. Overall, FGD participants expressed limited knowledge about the COVID-19 vaccine compared with health workers. Further, FGD participants from urban sites were more aware about the vaccine than those from rural areas. Health workers perceived the vaccine to be beneficial; the benefits included prevention of infection and limiting the severity of the disease. Moreover, FGD participants from urban sites expressed a negative attitude towards the vaccine. They believed the vaccine conferred no benefits. By contrast, participants from rural communities had mixed views; they needed more information about the vaccine benefits. Participants’ attitude seems to have been influenced by personal or family experience with the COVID-19 disease or vaccination; those who had experienced the disease had a more positive attitude. In contrast, most young people believed they were not at risk of the COVID-19 disease. Misinformation from social media influenced their attitude.Conclusion These results provide starting points for future policies and interventions for increasing COVID-19 vaccine uptake.

Surface-response functions are one of the most promising routes for bridging the gap between fully quantum-mechanical calculations and phenomenological models in quantum nanoplasmonics. Among all currently available recipes for obtaining such response functions, the use of ab initio methods remains one of the most conspicuous trends, wherein the surface-response functions are retrieved via the metal’s non-equilibrium response to an external time-dependent perturbation. Here, we present a complementary approach to approximate one of the most appealing surface-response functions, namely the Feibelman d-parameters, yield a finite contribution even when they are calculated solely with the equilibrium properties of the metal, described under the local-response approximation (LRA) but with a spatially varying equilibrium electron density, as input. Using model calculations that mimic both spill-in and spill-out of the equilibrium electron density, we show that the obtained d-parameters are in qualitative agreement with more elaborate, but also more computationally demanding, ab initio methods. The analytical work presented here illustrates how microscopic surface-response functions can emerge out of entirely local electrodynamic considerations.

Many children around the globe suffer from spider phobia. Virtual reality exposure therapy is an effective phobia treatment, but so far predominantly tailored for adults. A gamified approach utilizing gaze interaction would allow for a more child-friendly and engaging experience, and provide the possibility to foster working mechanisms of exposure therapy. We developed an application in which children make spiders change in positively connoted ways (e.g., make them dance or shrink) if sufficient visual attention towards them is captured via eye tracking. Thereby, motivation for and positive affects during exposure towards spiders are aspired. In this pilot study on 21 children without (n = 11) and with fear of spiders (n = 10), we examined positive and negative affect during exposure to a virtual spider and to different gaze-related transformations of the spider within a quasi-experimental design. Within a one-group design, we additionally examined fear of spiders in spider fearful children before and one week after the intervention. We found that significantly more positive than negative affect was induced by the spiders' transformations in children without and with fear of spiders. Fear of spiders was furthermore significantly reduced in spider-fearful children, showing large effect sizes (d >.80). Findings indicate eligibility for future clinical use and evaluation in children with spider phobia. [ABSTRACT FROM AUTHOR]

Light-matter interactions at the nanoscale constitute a fundamental ingredient for engineering applications in nanophotonics and quantum optics. In this regard, Mie resonances supported by high-refractive index dielectric nanoparticles have recently attracted interest, due to their lower losses and better control over the scattering patterns compared to their plasmonic counterparts. The emergence of several resonances in high-refractive index dielectric nanoparticles results in an overall high complexity, where the electric and magnetic dipoles can show a significant spectral overlap, especially at optical frequencies, thus hindering possible light-matter coupling mechanisms arising in the optical spectrum. This behavior can be properly adjusted by using non-spherical geometries, an approach that has already been successfully exploited to tune directional scattering from dielectric nanoresonators. Here, by using cylindrical nanoparticles, we show, experimentally and theoretically, the emergence of peak splitting for both magnetic and electric dipole resonances of individual silicon nanodisks coupled to a J-aggregated organic semiconductor. In the two cases, we find that the different character of the involved resonances leads to different light-matter coupling regimes. Crucially, our results show that the observed energy splittings are of the same order of magnitude as the ones reported using similar plasmonic systems, thereby confirming dielectric nanoparticles as promising alternatives for localized strong coupling studies. The coupling of both the electric and magnetic dipole resonances can offer interesting possibilities for the control of directional light scattering in the strong coupling regime and the dynamic tuning of nanoscale light-matter hybrid states by external fields.

Spin-orbit interactions (SOI), describing the transfer of a spin degree of freedom to an orbital angular momentum (OAM), have been widely explored in recent opto-acoustic studies for applications mainly in spintronics and for topological insulators [1]. We report the observation of SOI by Brillouin scattering in an optical nanofiber. Specifically, we describe the transfer of a spin degree of freedom from light incident to the nanofiber to an acoustic vortex with a topological charge of order 2 in the form of OAM. Coupled with the phase matching condition for the energy conservation during Brillouin scattering, it results in a backscattered wave with a spin opposite to the incident wave. This observation allows considering applications of opto-acoustic Brillouin memory based on polarization conversion through a SOI [2].

Background: This study investigated the application of a newly developed neuropsychological assessment, the Wolfenbütteler Dementia Test for Individuals with Intellectual Disabilities (WDTIM) in combination with the Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID). Methods: The instruments were evaluated in a prospective 2-year follow-up study. A total of 102 people with an intellectual disability were assessed at 6-month intervals. Data were analysed using qualitative and statistical analyses. Results: Four groups of individuals emerged from the analysis: (1) confirmed suspicion, (2) no suspicion, (3) questionable suspicion and (4) early suspicion. Significant differences were found between groups 1 and 2. The WDTIM could be administered to 90%-100% of all participants exhibiting mild-to-moderate intellectual disability and to 50% with severe intellectual disability. Conclusions: The WDTIM was shown to have good applicability to people with mild-to-moderate intellectual disability and to be appropriate for detecting cognitive changes. Using the two instruments in combination achieved greater accuracy in reinforcing a dementia suspicion than did using the DSQIID alone.

To optimize material stability, automated high-throughput workflows are of increasing interest. However, many of those workflows either employ synthesis techniques not suitable for large-area depositions or are carried out in ambient conditions, which limits the transferability of the results. While combinatorial approaches based on vapour-based depositions are inherently scalable, their potential for controlled stability assessments has yet to be exploited. Based on MAPbI3 thin films as a prototypical system, we demonstrate a combinatorial inert-gas workflow to study intrinsic materials degradation, closely resembling conditions in encapsulated devices. Specifically, we probe the stability of MAPbI3 thin films with varying residual PbI2 content. A comprehensive set of automated characterization techniques is used to investigate the structure and phase constitution of pristine and aged thin films. A custom-designed in situ UV-Vis aging setup is used for real-time photospectroscopy measurements of the material libraries under relevant aging conditions, such as heat or light-bias exposure. These measurements are used to gain insights into the degradation kinetics, which can be linked to intrinsic degradation processes such as autocatalytic decomposition. Despite scattering effects, which complicate the conventional interpretation of in situ UV-Vis results, we demonstrate how a machine learning model trained on the comprehensive characterization data before and after the aging process can link changes in the optical spectra to phase changes during aging. Consequently, this approach does not only enable semi-quantitative comparisons of material stability but also provides detailed insights into the underlying degradation processes which are otherwise mostly reported for investigations on single samples. [ABSTRACT FROM AUTHOR]

Hybrid vapor deposition is one of the most appealing processes for perovskite photovoltaics fabrication, thanks to its versatile nature. By using sequentially different vapor deposition processes tailored to the inorganic and organic perovskite precursors' peculiarities, this type of process gives access to the full potential of vapor deposition. While vapor deposition of metal halides is well understood and mastered, vapor deposition of organohalide species is much more delicate (degradation of vapors, high vapor pressure, setup‐specific constraints). Here, a novel close space sublimation system is reported and in‐depth insights on the conversion into perovskite of a metal halide template are provided. In this evolution of the process, the substrate coated with metal halide template and the organohalide source are loaded together in a dedicated holder, then transferred into a vacuum chamber on a heating element already at temperature setpoint. The system enables a simple, fast, low‐cost, and easy‐to‐reproduce organohalide vapor deposition process. The formation of the perovskite in situ and identification different conversion regimes are studied. Furthermore, the influence of the chemical environment and chamber design on the process are discussed. Compositional tuning and additive engineering in the process are processed and fabricate proof of concept photovoltaic devices reaching high fill factors of 80% and 17% power conversion efficiency for a bandgap of 1.63 eV. [ABSTRACT FROM AUTHOR]

We theoretically evaluate the impact of drift-free noise on the dynamics of PT${\cal P}{\cal T}$-symmetric non-Hermitian systems with an exceptional point, which have recently been proposed for sensors. Such systems are currently considered as promising templates for sensing applications, because of their intrinsically extremely sensitive response to external perturbations. However, this applies equally to the impact of fabrication imperfections and fluctuations in the system parameters. Here we focus on the influence of such fluctuations caused by inevitable (thermal) noise and show that the exceptional-point eigenstate is not stable in its presence. To this end, we derive an effective differential equation for the mean time evolution operator averaged over all realizations of the noise field, and via numerical analysis we find that the presence of noise leads to exponential divergence of any initial state after some characteristic period of time. We therefore show that it is rather demanding to design sensor systems based on continuous operation at an exceptional point.

Metal halide perovskites (MHPs) have become a widely studied class of semiconductors for various optoelectronic devices. The possibility to tune their bandgap (Eg) over a broad spectral range from 1.2 eV to 3 eV by compositional engineering makes them particularly attractive for light emitting devices and multi‐junction solar cells. In this metadata study, data from Peer‐reviewed publications available in the Perovskite Database (www.perovskitedatabase.com) is used to evaluate the current state of Eg tuning in wideEg MHP semiconductors. Recent literature on wide Eg MHP semiconductors is examined and the data is extracted and uploaded onto the Perovskite Database. Beyond describing recent highlights and scientific breakthroughs, general trends are drawn from 45,000 individual experimental datasets of MHP solar cell devices. The historical evolution of MHP solar cells is recapitulated, and general conclusions are drawn about the current limits of device performance. Three dominant causes are identified and discussed for the degradation of performance relative to the Shockley‐Queisser (SQ) model's theoretical limit for single‐junction solar cells: 1) energetically mismatched selective transport materials for wide Eg MHPs, 2) lower optoelectronic quality of wide Eg MHP absorbers, and 3) dynamically evolving compositional heterogeneity due to light‐induced phase segregation phenomena. [ABSTRACT FROM AUTHOR]

This article presents a method of emotion analysis for German drama from the 17th to the 19th century that significantly goes beyond previous research approaches in computational literary studies. It is based on annotations of 17 dramatic texts resulting in 11,939 annotations which were used as training material to fine-tune a German language BERT model that achieves an average accuracy of 73% for the single-label emotion classification of fourteen emotion types in cross-validation. We apply the emotion classification on a corpus of 141 comedies and 92 tragedies to compare these genres. For tragedies, the mean proportion percentages of 'suffering' and 'abhorrence' are higher than for comedies. Inversely, mean percentages of 'anger' and 'joy' are higher for comedies than for tragedies. A new finding is the surprisingly high proportion of 'anger' in comedies. Emotion distribution of the last scenes in dramatic texts also proves the quality of the classified data in terms of literary studies. In addition, the emotion distribution for several subgenres of comedy is investigated including non-canonical works of wide circulation which reached the recipients directly through the depicted emotions in the Kasperl Plays. Comedies from 1740 to 1770 are characterized by a pairing of higher amounts of 'friendship' and 'love'. Satirical comedies from the same period stand out due to high rates of 'anger' as well as 'suffering'. The very successful Kasperl plays turn out to be characterized by a comparatively large percentage of 'schadenfreude' and 'joy'. [ABSTRACT FROM AUTHOR]