Astrophysicists of the University of Tübingen have been involved in a large, worldwide collaborative effort to observe the black hole M87 and its jet system all across the electromagnetic spectrum, during the observation campaign conducted with the Event Horizon Telescope that led to the first image of a black hole.

Physikdidaktiker der Goethe-Universität und der Universität Tübingen (Jun.-Prof. Dr. Jan-Philipp Burde) haben ein neues, intuitives Lehrkonzept entwickelt und in einer großen Vergleichsstudie an Schulen getestet.

Versatile interfaces with strong and tunable light–matter interactions are essential for quantum science1 because they enable mapping of quantum properties between light and matter1. Recent studies2–10 have proposed a method of controlling light–matter interactions using the rich interplay of photon-mediated dipole–dipole interactions in structured subwavelength arrays of quantum emitters. However, a key aspect of this approach—the cooperative enhancement of the light–matter coupling strength and the directional mirror reflection of the incoming light using an array of quantum emitters—has not yet been experimentally demonstrated. Here we report the direct observation of the cooperative subradiant response of a two-dimensional square array of atoms in an optical lattice. We observe a spectral narrowing of the collective atomic response well below the quantum-limited decay of individual atoms into free space. Through spatially resolved spectroscopic measurements, we show that the array acts as an efficient mirror formed by a single monolayer of a few hundred atoms. By tuning the atom density in the array and changing the ordering of the particles, we are able to control the cooperative response of the array and elucidate the effect of the interplay of spatial order and dipolar interactions on the collective properties of the ensemble. Bloch oscillations of the atoms outside the array enable us to dynamically control the reflectivity of the atomic mirror. Our work demonstrates efficient optical metamaterial engineering based on structured ensembles of atoms4,8,9 and paves the way towards controlling many-body physics with light5,6,11 and light–matter interfaces at the single-quantum level.

eROSITA hat nach einem halben Jahr Survey-Betrieb nun seine erste vollständige Karte des Röntgenhimmels erstellt.
Die Karte wird am 24.6.2020 bei Astronomy Picture of the Day bei der NASA gezeigt

https://apod.nasa.gov/apod/ap200623.html