Photonic Quantum Logic with Narrowband Light from Single Atoms

Increasing control of single photons enables new applications of photonic quantum-enhanced technology and further experimental exploration of fundamental quantum phenomena. Here, we demonstrate quantum logic using narrow linewidth photons that are produced under nearly perfect quantum control from a single ^87Rb atom strongly coupled to a high-finesse cavity. We use a controlled- NOT gate integrated into a photonic chip to entangle these photons, and we observe non-classical correlations between events separated by periods exceeding the travel time across the chip by three orders of magnitude. This enables quantum technology that will use the properties of both narrowband single photon sources and integrated quantum photonics, such as networked quantum computing, narrow linewidth quantum enhanced sensing and atomic memories.Comment: 5 pates, 3 figure

Anspruch und Wirklichkeit der Leistenhernienversorgung in Westfalen-Lippe

Die Einführung neuer Verfahren zur Therapie der Leistenhernie hat nach Daten der Qualitätssicherung der Ärztekammer Westfalen-Lippe zu keiner Reduktion der Rezidivraten geführt. Es wurde eine kontrollierte Umfrage an 180 chirurgischen Kliniken durchgeführt. Es galt Fragen zur Diagnostik, Anästhesie, Operation, Mobilisation, Krankenhausaufenthaltsdauer (KVD) und Nachsorge zu beantworten. Die Ergebnisse des Klinikkollektivs (KK) wurden mit Daten der Ärztekammer (ÄK) abgeglichen. Der Rücklauf betrug 58%. Die Intubationsnarkose ist führend. Jungen Patienten mit primärer Leistenhernie werden nach Shouldice, ältere Patienten nach Lichtenstein (KK) oder nach Shouldice (ÄK) versorgt. Rezidivhernien werden nach Lichtenstein behandelt. Laparoskopischen Methoden kommen bei bilateralen Hernien zum Einsatz. Die KVD beträgt im KK 4-6 und im ÄK 6-10 Tage. Anspruch und Wirklichkeit der Leistenhernienversorgung stimmen auf Grund der signifikanten Unterschiede in Westfalen-Lippe nur bedingt überein

Identification, localization and classification of the color VEP for application in color science

Experimental research on the preference of a light stimulus still mostly relies on subjective feedback of participants which is why Electroencephalogram (EEG) recordings could meaningfully enrich those experiments by providing low-level psychological response data. There is little research on the influence of color on Visually Evoked Potentials (VEP) or the visual pathway regarding color perception and even less is known about visual processing with regards to color preference. This work shows that it is possible to both linearly separate EEG for differently colored stimuli as well as to spatially separate the VEPs with regards to different visual areas in the visual cortex all by employing a consumer-grade EEG device. High-luminance stimuli as well as the presented red stimuli produce higher peak VEPs than the produced lowluminance and green stimuli. Furthermore, the Color VEP seems to propagate from the primary visual cortex V1 towards the secondary visual cortex V2 which corroborates the assumptions of a hierarchical visual processing of color. This work was done in anticipation of further research which is meant to eventually find a link between color metrics, color preference and EEG features

Evaluating colour preference by using multidimensional approaches

Colour preference is a key factor in the design and evaluation of lighting systems, particularly with the emergence of multichannel LED systems which allow for greater control over the spectrum of light emitted and therefore the colour appearance of the illuminated objects. To more accurately and objectively measure colour preference, there has been a growing interest in the development of multidimensional evaluation algorithms that consider multiple dimensions of colour rendering, such as chroma and hue shift. The purpose of this study was to compare and evaluate the performance of different multidimensional evaluation algorithms for colour preference in lighting applications. Using computer-generated images of a coloured object displayed on a computer monitor under a fixed white point, we simulated the colour shifts of the object under different light sources and test subjects evaluated the results using a range of multidimensional methods. Our analysis revealed that there are significant differences in the performance of these algorithms, with some providing more accurate and reliable measures of colour preference than others. Considering all relevant criteria, genetic algorithms seem to provide the most promising approach, as they lead to a result quickly and reliably. These findings have important implications for the selection and use of multidimensional algorithms for evaluating colour preference in lighting, particularly in the context of multichannel LED systems, and can inform future research in this area

Simulation of Airbus-A320 fuselage surface pressure fluctuations at cruise conditions in "Aeroacoustics research in Europe: The CEAS-ASC report on 2019 highlights"

The fuselage surface pressure fluctuations on an Airbus-A320 aircraft at cruise conditions are simulated by solving a Poisson equation. The right-hand-side source terms of the Poisson equation, including both the mean-shear term and the turbulence-turbulence term, are realized with synthetic anisotropic turbulence generated by the Fast Random Particle-Mesh Method. The stochastic realization is based on time-averaged turbulence statistics derived from a RANS simulation under the same condition as in the flight tests, conducted with DLR's Airbus-A320 research aircraft. The fuselage surface pressure fluctuations are calculated at three streamwise positions from front to rear corresponding to the measurement positions in the flight tests. One- and two-point spectral features of the pressure fluctuations relevant to the fuselage surface excitation are obtained and analysed

Untersuchung der Duv-Präferenz in Abhängigkeit von korrelierter Farbtemperatur (CCT), Farbgamut und betrachteten Objekten

Der Weißpunkt einer im Innenraum verwendeten LED-Lichtquelle hat einen entscheidenden Einfluss darauf, ob Menschen die Beleuchtung akzeptieren oder nicht. Daher wurden in den letzten Jahren vermehrt Präferenzuntersuchungen zum Weißpunkt durchgeführt, um die Innenraumbeleuchtung mit LED zu optimieren. Die Studienergebnisse zeigten, dass die Testpersonen bei verschiedenen CCTs negative Duv-Werte präferieren. Allerdings wurde bei diesen Studien weder eine Einordnung in einen bestimmten Kontext vorgenommen, noch die Auswahl vorhandener und beleuchteter, farbiger Objekte begründet. Deshalb wurde im Rahmen einer eigenen Probandenstudie untersucht, welchen Einfluss die korrelierte Farbtemperatur, der Farbgamut und die betrachteten Objekte auf den präferierten Duv-Wert und somit Weißpunkt haben. Die Untersuchung ergab, dass für die CCT 4000 K Duv-Werte zwischen -0,0045 und -0,0015, also nahe des Planck’schen Kurvenzugs, präferiert wurden. Farbige Objekte hatten keinen signifikanten Einfluss auf die Präferenz. Der Einfluss des Farbgamuts konnte nicht vollständig geklärt werden

High‐resolution depth measurements in digital microscopic surgery

Fully digital microscopes are becoming more and more common in surgical applications. In addition to high‐resolution stereoscopic images of the operating field, which can be transmitted over long distances or stored directly, these systems offer further potentials by supporting the surgical workflow based on their fully digital image processing chain. For example, the image display can be adapted to the respective surgical scenario by adaptive color reproduction optimization or image overlays with additional information, such as the tissue topology. Knowledge of this topology can be used for computer‐assisted or augmented‐reality‐guided microsurgical treatments and enables additional features such as spatially resolved spectral reconstruction of surface reflectance. In this work, a new method for high‐resolution depth measurements in digital microsurgical applications is proposed, which is based on the principle of laser triangulation. Part of this method is a sensor data fusion procedure to properly match the laser scanner and camera data. In this context, a strategy based on radial basis function interpolation techniques is presented to handle missing or corrupt data, which, due to the measuring principle, can occur on steep edges and through occlusion. The proposed method is used for the acquisition of high‐resolution depth profiles of various organic tissue samples, proving the feasibility of the proposed concept as a supporting technology in a digital microsurgical workflow

Fast Excitation and Photon Emission of a Single-Atom-Cavity System

We report on the fast excitation of a single atom coupled to an optical cavity using laser pulses that are much shorter than all other relevant processes. The cavity frequency constitutes a control parameter that allows the creation of single photons in a superposition of two tunable frequencies. Each photon emitted from the cavity thus exhibits a pronounced amplitude modulation determined by the oscillatory energy exchange between the atom and the cavity. Our technique constitutes a versatile tool for future quantum networking experiments.Comment: 4 pages, 5 figure

Fuselage Excitation During Cruise Flight Conditions: Measurement and Prediction of Pressure Point Spectra

In the last �fifty years many semi-empirical models to predict surface pressure fluctuations beneath turbulent boundary layers (TBL) have been developed for a large variety of test conditions. Nowadays, the relevance of the TBL as a source of cabin interior noise is steadily increasing, due to quieter aircraft engines. The possibility of predicting surface pressure auto-spectra with the various publicly available semi-empirical models at several positions on the fuselage of DLR's Advanced Technology Research Aircraft (ATRA) is investigated. A large validation database was used, involving in-flight measurements at different flight levels (FL) and Mach numbers, applying two different sensor types. Predictions were performed based on semi-empirically estimated TBL parameters (partly included in the different models) and, additionally, based on TBL properties that were extracted from CFD simulations. This procedure served to identify different sources of error in the prediction. Overall, it is shown that today's models provide a large (> 10 dB) scatter among the predicted spectra. Even the most suitable approaches are not generally applicable to all relevant positions at the fuselage. Particularly in regions with strong pressure gradients and high turbulence kinetic energy measured auto-spectra cannot be reproduced with su�fficient accuracy. This indicates the need for more universally applicable CFD- and CAA-based surface pressure prediction methods