The emergence of spatial and temporal coherence of light emitted from solid-state systems is a fundamental phenomenon intrinsically aligned with the control of light-matter coupling. It is canonical for laser oscillation, emerges in the superradiance of collective emitters, and has been investigated in bosonic condensates of thermalized light, as well as exciton-polaritons. Our room temperature experiments show the strong light-matter coupling between microcavity photons and excitons in atomically thin WSe2. We evidence the density-dependent expansion of spatial and temporal coherence of the emitted light from the spatially confined system ground-state, which is accompanied by a threshold-like response of the emitted light intensity. Additionally, valley-physics is manifested in the presence of an external magnetic field, which allows us to manipulate K and K’ polaritons via the valley-Zeeman-effect. Our findings validate the potential of atomically thin crystals as versatile components of coherent light-sources, and in valleytronic applications at room temperature.

Zusammenfassung Hintergrund und Ziel Arbeitslosigkeit steht in Zusammenhang mit Armut und ist ein Risikofaktor für schlechte Gesundheit. Der vorliegende Beitrag untersucht, ob Arbeitslosigkeit das Risiko für einen COVID-19-bedingten Krankenhausaufenthalt für Männer und Frauen im erwerbsfähigen Alter in Deutschland erhöht. Methoden Die Auswertungen verwenden Krankenkassendaten der AOK Rheinland/Hamburg (vom 01.01.2020 bis zum 18.06.2020) mit Daten zu 1.288.745 Personen zwischen 18 und 65 Jahren. 4 Erwerbssituationen werden unterschieden: (1) reguläre Erwerbstätigkeit, (2) Niedriglohntätigkeit mit Sozialleistungen, (3) Arbeitslosigkeit mit Bezug von Arbeitslosengeld 1 (Alg I) und (4) Langzeitarbeitslosigkeit mit Bezug von Arbeitslosengeld 2 (Alg II). COVID-19-Krankenhausaufenthalte werden über Meldungen der Krankenhäuser anhand der ICD-Codes U07.1 und U07.2 bestimmt. Berechnet werden multiple logistische Regressionsmodelle (für Alter und Geschlecht adjustiert). Ergebnisse 1521 Personen hatten im Beobachtungszeitraum einen Krankenhausaufenthalt mit COVID-19 als Haupt- oder als Nebendiagnose. Dies entspricht insgesamt einer Rate von 118 Fällen pro 100.000 Versicherten. Die Raten variieren je nach Erwerbssituation. Im Vergleich zu regulär Erwerbstätigen liegt das Odds Ratio im Falle von Langzeitarbeitslosigkeit (Alg II) bei 1,94 (KI 95 %: 1,74–2,15), für Empfänger von Alg I bei 1,29 (KI 95 %: 0,86–1,94) und für Niedriglohnverdiener bei 1,33 (KI 95 %: 0,98–1,82). Schlussfolgerung Die Ergebnisse stimmen mit früheren Studien aus den USA und Großbritannien zu sozioökonomischen Ungleichheiten bzgl. Risikos von COVID-19-Krankenhausaufenthalten überein. Dies liefert erste Hinweise dafür, dass sozioökonomische Unterschiede in Bezug auf schwere Verläufe von COVID-19 auch in Deutschland auftreten.

Engineering the properties of quantum materials via strong light-matter coupling is a compelling research direction with a multiplicity of modern applications. Those range from modifying charge transport in organic molecules, steering particle correlation and interactions, and even controlling chemical reactions. Here, we study the modification of the material properties via strong coupling and demonstrate an effective inversion of the excitonic band-ordering in a monolayer of WSe2 with spin-forbidden, optically dark ground state. In our experiments, we harness the strong light-matter coupling between cavity photon and the high energy, spin-allowed bright exciton, and thus creating two bright polaritonic modes in the optical bandgap with the lower polariton mode pushed below the WSe2 dark state. We demonstrate that in this regime the commonly observed luminescence quenching stemming from the fast relaxation to the dark ground state is prevented, which results in the brightening of this intrinsically dark material. We probe this effective brightening by temperature-dependent photoluminescence, and we find an excellent agreement with a theoretical model accounting for the inversion of the band ordering and phonon-assisted polariton relaxation.

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IntroductionWomen with gestational diabetes mellitus (GDM) have a higher risk of developing type 2 diabetes mellitus compared with women who never had GDM. Consequently, the question of structured aftercare for GDM has emerged. In all probability, many women do not receive care according to the guidelines. In particular, the process and interaction between obstetrical, diabetic, gynaecological, paediatric and general practitioner care lacks clear definitions. Thus, our first goal is to analyse the current aftercare situation for women with GDM in Germany, for example, the participation rate in aftercare diabetes screening, as well as reasons and attitudes stated by healthcare providers to offer these services and by patients to participate (or not). Second, we want to develop an appropriate, effective and patient-centred care model.Methods and analysisThis is a population-based mixed methods study using both quantitative and qualitative research approaches. In various working packages, we evaluate data of the GestDiab register, of the Association of Statutory Health Insurance Physicians of North Rhine and the participating insurance companies (AOK Rheinland/Hamburg, BARMER, DAK Gesundheit, IKK classic, pronova BKK). In addition, quantitative (postal surveys) and qualitative (interviews) surveys will be conducted with randomly selected healthcare providers (diabetologists, gynaecologists, paediatricians and midwives) and affected women, to be subsequently analysed. All results will then be jointly examined and evaluated.Ethics and disseminationThe study was approved by the ethics committee of the Faculty of Medicine, Heinrich-Heine-University Düsseldorf (Ethics Committee No.: 2019-738). Participants of the postal surveys and interviews will be informed in detail about the study and the use of data as well as the underlying data protection regulations before voluntarily participating. The study results will be disseminated through peer-reviewed journals, conferences and public information.Trial registration numberDRKS00020283.