Neolithic transverse arrowheads: a great misunderstanding

One of the most debated subjects in archaeology is the transition between the Mesolithic and the Neolithic period. A missing piece in this debate has been the transverse arrowhead, which is a relic from the hunting and gathering society but still has its place in the new agrarian societies. What we think we know about transverse arrowheads from Southern Scandinavia is based on a more than 75 years old theory, which hypothesises that Neolithic arrowheads were manufactured from irregular or polished flakes. This article offers a critical review of research so far into transverse arrowheads in Southern Scandinavia. It does so by proposing a new typo-chronology of Neolithic arrowheads from this region, which demonstrates how the transverse arrowhead developed from the Late Mesolithic to the Middle Neolithic, and it is actually the first study with the main focus on this subject. The study is concluded with a discussion that argues the empirical basis for the typological restructuring and highlights the implications of the study for the broader debate on Neolithisation

Edge State Quantization: Vector Fields in Rindler

We present a detailed discussion of the entanglement structure of vector fields through canonical quantization. We quantize Maxwell theory in Rindler space in Lorenz gauge, discuss the Hilbert space structure and analyze the Unruh effect. As a warm-up, in 1+1 dimensions, we compute the spectrum and prove that the theory is thermodynamically trivial. In d+1 dimensions, we identify the edge sector as eigenstates of horizon electric flux or equivalently as states representing large gauge transformations, localized on the horizon. The edge Hilbert space is generated by inserting a generic combination of Wilson line punctures in the edge vacuum, and the edge states are identified as Maxwell microstates of the black hole. This construction is repeated for Proca theory. Extensions to tensor field theories, and the link with Chern-Simons are discussed.Comment: 57 pages, v2: minor modifications and references added, matches published versio

Class attendance, peer similarity, and academic performance in a large field study

Identifying the factors that determine academic performance is an essential part of educational research. Existing research indicates that class attendance is a useful predictor of subsequent course achievements. The majority of the literature is, however, based on surveys and self-reports, methods which have well-known systematic biases that lead to limitations on conclusions and generalizability as well as being costly to implement. Here we propose a novel method for measuring class attendance that overcomes these limitations by using location and bluetooth data collected from smartphone sensors. Based on measured attendance data of nearly 1,000 undergraduate students, we demonstrate that early and consistent class attendance strongly correlates with academic performance. In addition, our novel dataset allows us to determine that attendance among social peers was substantially correlated ($>$0.5), suggesting either an important peer effect or homophily with respect to attendance

Epitaxial lift-off for solid-state cavity quantum electrodynamics

We present a new approach to incorporate self-assembled quantum dots into a Fabry-P\'{e}rot-like microcavity. Thereby a 3$\lambda$/4 GaAs layer containing quantum dots is epitaxially removed and attached by van der Waals bonding to one of the microcavity mirrors. We reach a finesse as high as 4,100 with this configuration limited by the reflectivity of the dielectric mirrors and not by scattering at the semiconductor - mirror interface, demonstrating that the epitaxial lift-off procedure is a promising procedure for cavity quantum electrodynamics in the solid state. As a first step in this direction, we demonstrate a clear cavity-quantum dot interaction in the weak coupling regime with a Purcell factor in the order of 3. Estimations of the coupling strength via the Purcell factor suggests that we are close to the strong coupling regime.Comment: 6 pages, 4 figure

Die Bankenmärkte Russlands und Bulgariens

Die durch jahrzehntelange Planwirtschaft geprägten Strukturen sind in Russland noch fest verwurzelt. Dementsprechend ist das Bankensystem auch zwölf Jahre nach dem Ende des kommunistischen Regimes unterentwickelt. Die markantesten Merkmale der Finanzwirtschaft sind die ungewöhnliche Größenstruktur der Banken; deren Schwierigkeiten, die rapide zunehmende Zahl kleinster, kleiner und mittlerer Unternehmen mit Finanzdienstleistungen zu versorgen sowie die geringe Rolle ausländischer Banken. Überdies sind die weiterhin bestehenden Systemrisiken nicht zu unterschätzen