Observation of squeezed light with 10dB quantum noise reduction

Squeezing of light's quantum noise requires temporal rearranging of photons. This again corresponds to creation of quantum correlations between individual photons. Squeezed light is a non-classical manifestation of light with great potential in high-precision quantum measurements, for example in the detection of gravitational waves. Equally promising applications have been proposed in quantum communication. However, after 20 years of intensive research doubts arose whether strong squeezing can ever be realized as required for eminent applications. Here we show experimentally that strong squeezing of light's quantum noise is possible. We reached a benchmark squeezing factor of 10 in power (10dB). Thorough analysis reveals that even higher squeezing factors will be feasible in our setup.Comment: 10 pages, 4 figure

Argumentieren lernen. Aufgaben für den Philosophie- und Ethikunterricht

Erarbeitet von Dominik Balg, Anne Burkard, Henning Franzen, Aenna Frottier, David Lanius, David Löwenstein, Hanna Lucks, Kirsten Meyer, Donata Romizi, Katharina Schulz, Stefanie Thiele und Annett Wienmeister. Die Entwicklung argumentativer Fähigkeiten ist ein zentrales Ziel des Ethik- und Philosophieunterrichts, ja überhaupt ein zentrales Bildungsziel. Wie aber kann das gelingen? In vielen verfügbaren Unterrichtsmaterialien werden argumentative Fähigkeiten eher vorausgesetzt als systematisch gefördert. Auch curriculare Vorgaben bleiben zumeist sehr unspezifisch. Lehrpersonen werden so weitgehend allein gelassen mit der Aufgabe, Lernende beim Erwerb argumentativer Fähigkeiten zu fördern. Die vorliegende Aufgabensammlung soll dazu beitragen, diese Lücke zu schließen. Sie bietet Lehrpersonen reichhaltige Materialien für die spiralcurricular angelegte, systematische Förderung argumentativer Fähigkeit anhand exemplarischer Inhalte. Orientiert an klaren fachlichen Standards finden sich hier Aufgaben auf vier Niveaustufen, jeweils in Verbindung mit übersichtlichen Merkblättern. Die Aufgaben der beiden unteren Niveaustufen lassen sich bereits für jüngere Lernende der Sekundarstufe einsetzen, Aufgaben der obersten Niveaustufe richten sich an Lernende von Abschlussklassen oder der Studieneingangsphase. Für die Hand der Lehrpersonen werden die Aufgaben und Merkblätter durch fachliche und didaktische Kommentare sowie Lösungshinweise ergänzt

Stress hormones: cortisol, adrenocorticotropic hormone and oxytocin in the context of social violations in children with autism spectrum disorders

Autism spectrum disorders (ASD) refer to heterogeneous disorders of neurodevelopment, the main symptom of which is social insufficiency. Aim: to conduct a one-stage assessment of the relationship between key hormones in the regulation of social and stress responses: adrenocorticotropic hormone (ACTH), cortisol, oxytocin, in children with ASD in the context of severe social insufficiency. Materials and methods. A total of 44 children (37 boys and 7 girls) aged 3 to 12 years with a diagnosis of ASD were examined, which were divided into groups: with preserved social contact / lack of it. The concentrations of hormones were evaluated in blood plasma by the method of ELISA. Results. ACTH and cortisol demonstrate interdependent relationships without the involvement of oxytocin in children with ASD, while maintaining their social contact. In children with ASD with symptoms of social insufficiency, there are no correlations between the studied neurohormones. The conclusion. The data obtained suggest that the processes of disorganization / destruction of neuroanatomical and physiological connections between the systems of oxytocin and the hypothalamic-pituitary-adrenal axis (HPA-axis) and (or) the hypothalamic-neurohypophysis system and the HPA-axis

Argumentative Skills: A Systematic Framework for Teaching and Learning

In this paper, we propose a framework for fostering argumentative skills in a systematic way in Philosophy and Ethics classes. We start with a review of curricula and teaching materials from the German-speaking world to show that there is an urgent need for standards for the teaching and learning of argumentation. Against this backdrop, we present a framework for such standards that is intended to tackle these difficulties. The spiral-curricular model of argumentative competences we sketch helps teachers introduce the relevant concepts and skills to students early on in their school career. The focus is on secondary schools, but the proposal can also be of use for learning and teaching in universities, especially in introductory classes

Experimental characterization of frequency dependent squeezed light

We report on the demonstration of broadband squeezed laser beams that show a frequency dependent orientation of the squeezing ellipse. Carrier frequency as well as quadrature angle were stably locked to a reference laser beam at 1064nm. This frequency dependent squeezing was characterized in terms of noise power spectra and contour plots of Wigner functions. The later were measured by quantum state tomography. Our tomograph allowed a stable lock to a local oscillator beam for arbitrary quadrature angles with one degree precision. Frequency dependent orientations of the squeezing ellipse are necessary for squeezed states of light to provide a broadband sensitivity improvement in third generation gravitational wave interferometers. We consider the application of our system to long baseline interferometers such as a future squeezed light upgraded GEO600 detector.Comment: 8 pages, 8 figure

Observation of continuous-wave squeezed light at 1550 nm

We report on the generation of continuous-wave squeezed vacuum states of light at the telecommunication wavelength of 1550 nm. The squeezed vacuum states were produced by type I optical parametric amplification (OPA) in a standing-wave cavity built around a periodically poled potassium titanyl phosphate (PPKTP) crystal. A non-classical noise reduction of 5.3 dB below the shot noise was observed by means of balanced homodyne detection.Comment: 4 pages, 3 figure

The skeletal phenotype of chondroadherin deficient mice

Chondroadherin, a leucine rich repeat extracellular matrix protein with functions in cell to matrix interactions, binds cells via their a2b1 integrin as well as via cell surface proteoglycans, providing for different sets of signals to the cell. Additionally, the protein acts as an anchor to the matrix by binding tightly to collagens type I and II as well as type VI. We generated mice with inactivated chondroadherin gene to provide integrated studies of the role of the protein. The null mice presented distinct phenotypes with affected cartilage as well as bone. At 3–6 weeks of age the epiphyseal growth plate was widened most pronounced in the proliferative zone. The proteome of the femoral head articular cartilage at 4 months of age showed some distinct differences, with increased deposition of cartilage intermediate layer protein 1 and fibronectin in the chondroadherin deficient mice, more pronounced in the female. Other proteins show decreased levels in the deficient mice, particularly pronounced for matrilin-1, thrombospondin-1 and notably the members of the a1-antitrypsin family of proteinase inhibitors as well as for a member of the bone morphogenetic protein growth factor family. Thus, cartilage homeostasis is distinctly altered. The bone phenotype was expressed in several ways. The number of bone sialoprotein mRNA expressing cells in the proximal tibial metaphysic was decreased and the osteoid surface was increased possibly indicating a change in mineral metabolism. Micro-CT revealed lower cortical thickness and increased structure model index, i.e. the amount of plates and rods composing the bone trabeculas. The structural changes were paralleled by loss of function, where the null mice showed lower femoral neck failure load and tibial strength during mechanical testing at 4 months of age. The skeletal phenotype points at a role for chondroadherin in both bone and cartilage homeostasis, however, without leading to altered longitudinal growth

Molecular characterization of beta-tubulin from Phakopsora pachyrhizi, the causal agent of Asian soybean rust

β-tubulins are structural components of microtubules and the targets of benzimidazole fungicides used to control many diseases of agricultural importance. Intron polymorphisms in the intron-rich genes of these proteins have been used in phylogeographic investigations of phytopathogenic fungi. In this work, we sequenced 2764 nucleotides of the β-tubulin gene (Pp tubB) in samples of Phakopsora pachyrhizi collected from seven soybean fields in Brazil. Pp tubB contained an open reading frame of 1341 nucleotides, including nine exons and eight introns. Exon length varied from 14 to 880 nucleotides, whereas intron length varied from 76 to 102 nucleotides. The presence of only four polymorphic sites limited the usefulness of Pp tubB for phylogeographic studies in P. pachyrhizi. The gene structures of Pp tubB and orthologous β-tubulin genes of Melampsora lini and Uromyces viciae-fabae were highly conserved. The amino acid substitutions in β-tubulin proteins associated with the onset of benzimidazole resistance in model organisms, especially at His 6 , Glu 198 and Phe 200 , were absent from the predicted sequence of the P. pachyrhizi β-tubulin protein

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

Argumentative Skills: A Systematic Framework for Teaching and Learning

In this paper, we propose a framework for fostering argumentative skills in a systematic way in Philosophy and Ethics classes. We start with a review of curricula and teaching materials from the German-speaking world to show that there is an urgent need for standards for the teaching and learning of argumentation. Against this backdrop, we present a framework for such standards that is intended to tackle these difficulties. The spiral-curricular model of argumentative competences we sketch helps teachers introduce the relevant concepts and skills to students early on in their school career. The focus is on secondary schools, but the proposal can also be of use for learning and teaching in universities, especially in introductory classes