@article{RauHeindelUnsleberetal.2014, author = {Rau, Markus and Heindel, Tobias and Unsleber, Sebastian and Braun, Tristan and Fischer, Julian and Frick, Stefan and Nauerth, Sebastian and Schneider, Christian and Vest, Gwenaelle and Reitzenstein, Stephan and Kamp, Martin and Forchel, Alfred and H{\"o}fling, Sven and Weinfurter, Harald}, title = {Free space quantum key distribution over 500 meters using electrically driven quantum dot single-photon sources-a proof of principle experiment}, series = {New Journal of Physics}, volume = {16}, journal = {New Journal of Physics}, number = {043003}, doi = {10.1088/1367-2630/16/4/043003}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116760}, year = {2014}, abstract = {Highly efficient single-photon sources (SPS) can increase the secure key rate of quantum key distribution (QKD) systems compared to conventional attenuated laser systems. Here we report on a free space QKD test using an electrically driven quantum dot single-photon source (QD SPS) that does not require a separate laser setup for optical pumping and thus allows for a simple and compact SPS QKD system. We describe its implementation in our 500 m free space QKD system in downtown Munich. Emulating a BB84 protocol operating at a repetition rate of 125 MHz, we could achieve sifted key rates of 5-17 kHz with error ratios of 6-9\% and g((2))(0)-values of 0.39-0.76.}, language = {en} } @article{KimZhangWangetal.2016, author = {Kim, Seonghoon and Zhang, Bo and Wang, Zhaorong and Fischer, Julian and Brodbeck, Sebastian and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven and Deng, Hui}, title = {Coherent Polariton Laser}, series = {Physical Review X}, volume = {6}, journal = {Physical Review X}, number = {011026}, doi = {10.1103/PhysRevX.6.011026}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166597}, year = {2016}, abstract = {The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.}, language = {en} } @article{KempertGoetzBlatteretal.2016, author = {Kempert, Sebastian and G{\"o}tz, Regina and Blatter, Kristine and Tibken, Catharina and Artelt, Cordula and Schneider, Wolfgang and Stanat, Petra}, title = {Training Early Literacy Related Skills: To Which Degree Does a Musical Training Contribute to Phonological Awareness Development?}, series = {Frontiers in Psychology}, volume = {7}, journal = {Frontiers in Psychology}, number = {1803}, doi = {10.3389/fpsyg.2016.01803}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165272}, year = {2016}, abstract = {Well-developed phonological awareness skills are a core prerequisite for early literacy development. Although effective phonological awareness training programs exist, children at risk often do not reach similar levels of phonological awareness after the intervention as children with normally developed skills. Based on theoretical considerations and first promising results the present study explores effects of an early musical training in combination with a conventional phonological training in children with weak phonological awareness skills. Using a quasi-experimental pretest-posttest control group design and measurements across a period of 2 years, we tested the effects of two interventions: a consecutive combination of a musical and a phonological training and a phonological training alone. The design made it possible to disentangle effects of the musical training alone as well the effects of its combination with the phonological training. The outcome measures of these groups were compared with the control group with multivariate analyses, controlling for a number of background variables. The sample included N = 424 German-speaking children aged 4-5 years at the beginning of the study. We found a positive relationship between musical abilities and phonological awareness. Yet, whereas the well-established phonological training produced the expected effects, adding a musical training did not contribute significantly to phonological awareness development. Training effects were partly dependent on the initial level of phonological awareness. Possible reasons for the lack of training effects in the musical part of the combination condition as well as practical implications for early literacy education are discussed.}, language = {en} } @article{LundtKlembtCherotchenkoetal.2016, author = {Lundt, Nils and Klembt, Sebastian and Cherotchenko, Evgeniia and Betzold, Simon and Iff, Oliver and Nalitov, Anton V. and Klaas, Martin and Dietrich, Christof P. and Kavokin, Alexey V. and H{\"o}fling, Sven and Schneider, Christian}, title = {Room-temperature Tamm-plasmon exciton-polaritons with a WSe\(_{2}\) monolayer}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms13328}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169470}, year = {2016}, abstract = {Solid-state cavity quantum electrodynamics is a rapidly advancing field, which explores the frontiers of light-matter coupling. Metal-based approaches are of particular interest in this field, as they carry the potential to squeeze optical modes to spaces significantly below the diffraction limit. Transition metal dichalcogenides are ideally suited as the active material in cavity quantum electrodynamics, as they interact strongly with light at the ultimate monolayer limit. Here, we implement a Tamm-plasmon-polariton structure and study the coupling to a monolayer of WSe\(_{2}\), hosting highly stable excitons. Exciton-polariton formation at room temperature is manifested in the characteristic energy-momentum dispersion relation studied in photoluminescence, featuring an anti-crossing between the exciton and photon modes with a Rabi-splitting of 23.5 meV. Creating polaritonic quasiparticles in monolithic, compact architectures with atomic monolayers under ambient conditions is a crucial step towards the exploration of nonlinearities, macroscopic coherence and advanced spinor physics with novel, low-mass bosons.}, language = {en} } @article{DoerckGoebelWeiseetal.2010, author = {Doerck, Sebastian and Goebel, Kerstin and Weise, Gesa and Schneider-Hohendorf, Tilman and Reinhardt, Michael and Hauff, Peter and Schwab, Nicholas and Linker, Ralf and Maeurer, Mathias and Meuth, Sven G. and Wiendl, Heinz}, title = {Temporal Pattern of ICAM-I Mediated Regulatory T Cell Recruitment to Sites of Inflammation in Adoptive Transfer Model of Multiple Sclerosis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68565}, year = {2010}, abstract = {Migration of immune cells to the target organ plays a key role in autoimmune disorders like multiple sclerosis (MS). However, the exact underlying mechanisms of this active process during autoimmune lesion pathogenesis remain elusive. To test if pro-inflammatory and regulatory T cells migrate via a similar molecular mechanism, we analyzed the expression of different adhesion molecules, as well as the composition of infiltrating T cells in an in vivo model of MS, adoptive transfer experimental autoimmune encephalomyelitis in rats. We found that the upregulation of ICAM-I and VCAM-I parallels the development of clinical disease onset, but persists on elevated levels also in the phase of clinical remission. However, the composition of infiltrating T cells found in the developing versus resolving lesion phase changed over time, containing increased numbers of regulatory T cells (FoxP3) only in the phase of clinical remission. In order to test the relevance of the expression of cell adhesion molecules, animals were treated with purified antibodies to ICAM-I and VCAM-I either in the phase of active disease or in early remission. Treatment with a blocking ICAM-I antibody in the phase of disease progression led to a milder disease course. However, administration during early clinical remission aggravates clinical symptoms. Treatment with anti-VCAM-I at different timepoints had no significant effect on the disease course. In summary, our results indicate that adhesion molecules are not only important for capture and migration of pro-inflammatory T cells into the central nervous system, but also permit access of anti-inflammatory cells, such as regulatory T cells. Therefore it is likely to assume that intervention at the blood brain barrier is time dependent and could result in different therapeutic outcomes depending on the phase of CNS lesion development.}, subject = {Multiple Sklerose}, language = {en} } @article{AmthorWeissenseelFischeretal.2014, author = {Amthor, Matthias and Weißenseel, Sebastian and Fischer, Julian and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven}, title = {Electro-optical switching between polariton and cavity lasing in an InGaAs quantum well microcavity}, doi = {10.1364/OE.22.031146}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111130}, year = {2014}, abstract = {We report on the condensation of microcavity exciton polaritons under optical excitation in a microcavity with four embedded InGaAs quantum wells. The polariton laser is characterized by a distinct nonlinearity in the input-output-characteristics, which is accompanied by a drop of the emission linewidth indicating temporal coherence and a characteristic persisting emission blueshift with increased particle density. The temporal coherence of the device at threshold is underlined by a characteristic drop of the second order coherence function to a value close to 1. Furthermore an external electric field is used to switch between polariton regime, polariton condensate and photon lasing.}, language = {en} } @article{MaierGoldForcheletal.2014, author = {Maier, Sebastian and Gold, Peter and Forchel, Alfred and Gregersen, Niels and Mork, Jesper and H{\"o}fling, Sven and Schneider, Christian and Kamp, Martin}, title = {Bright single photon source based on self-aligned quantum dot-cavity systems}, series = {Optics Express}, volume = {22}, journal = {Optics Express}, number = {7}, issn = {1094-4087}, doi = {10.1364/OE.22.008136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119801}, pages = {8136-42}, year = {2014}, abstract = {We report on a quasi-planar quantum-dot-based single-photon source that shows an unprecedented high extraction efficiency of 42\% without complex photonic resonator geometries or post-growth nanofabrication. This very high efficiency originates from the coupling of the photons emitted by a quantum dot to a Gaussian shaped nanohill defect that naturally arises during epitaxial growth in a self-aligned manner. We investigate the morphology of these defects and characterize the photonic operation mechanism. Our results show that these naturally arising coupled quantum dot-defects provide a new avenue for efficient (up to 42\% demonstrated) and pure (g(2)(0) value of 0.023) single-photon emission.}, language = {en} } @article{YuNatarajanHorikirietal.2015, author = {Yu, Leo and Natarajan, Chandra M. and Horikiri, Tomoyuki and Langrock, Carsten and Pelc, Jason S. and Tanner, Michael G. and Abe, Eisuke and Maier, Sebastian and Schneider, Christian and H{\"o}fling, Sven and Kamp, Martin and Hadfield, Robert H. and Fejer, Martin M. and Yamamoto, Yoshihisa}, title = {Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, doi = {10.1038/ncomms9955}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138677}, pages = {8955}, year = {2015}, abstract = {Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances.}, language = {en} } @article{ManchiaAdliAkulaetal.2013, author = {Manchia, Mirko and Adli, Mazda and Akula, Nirmala and Arda, Raffaella and Aubry, Jean-Michel and Backlund, Lena and Banzato, Claudio E. M. and Baune, Bernhard T. and Bellivier, Frank and Bengesser, Susanne and Biernacka, Joanna M. and Brichant-Petitjean, Clara and Bui, Elise and Calkin, Cynthia V. and Cheng, Andrew Tai Ann and Chillotti, Caterina and Cichon, Sven and Clark, Scott and Czerski, Piotr M. and Dantas, Clarissa and Del Zompo, Maria and DePaulo, J. Raymond and Detera-Wadleigh, Sevilla D. and Etain, Bruno and Falkai, Peter and Fris{\´e}n, Louise and Frye, Mark A. and Fullerton, Jan and Gard, S{\´e}bastien and Garnham, Julie and Goes, Fernando S. and Grof, Paul and Gruber, Oliver and Hashimoto, Ryota and Hauser, Joanna and Heilbronner, Urs and Hoban, Rebecca and Hou, Liping and Jamain, St{\´e}phane and Kahn, Jean-Pierre and Kassem, Layla and Kato, Tadafumi and Kelsoe, John R. and Kittel-Schneider, Sarah and Kliwicki, Sebastian and Kuo, Po-Hsiu and Kusumi, Ichiro and Laje, Gonzalo and Lavebratt, Catharina and Leboyer, Marion and Leckband, Susan G. and L{\´o}pez Jaramillo, Carlos A. and Maj, Mario and Malafosse, Alain and Martinsson, Lina and Masui, Takuya and Mitchell, Philip B. and Mondimore, Frank and Monteleone, Palmiero and Nallet, Audrey and Neuner, Maria and Nov{\´a}k, Tom{\´a}s and O'Donovan, Claire and {\"O}sby, Urban and Ozaki, Norio and Perlis, Roy H. and Pfennig, Andrea and Potash, James B. and Reich-Erkelenz, Daniela and Reif, Andreas and Reininghaus, Eva and Richardson, Sara and Rouleau, Guy A. and Rybakowski, Janusz K. and Schalling, Martin and Schofield, Peter R. and Schubert, Oliver K. and Schweizer, Barbara and Seem{\"u}ller, Florian and Grigoroiu-Serbanescu, Maria and Severino, Giovanni and Seymour, Lisa R. and Slaney, Claire and Smoller, Jordan W. and Squassina, Alessio and Stamm, Thomas and Steele, Jo and Stopkova, Pavla and Tighe, Sarah K. and Tortorella, Alfonso and Turecki, Gustavo and Wray, Naomi R. and Wright, Adam and Zandi, Peter P. and Zilles, David and Bauer, Michael and Rietschel, Marcella and McMahon, Francis J. and Schulze, Thomas G. and Alda, Martin}, title = {Assessment of Response to Lithium Maintenance Treatment in Bipolar Disorder: A Consortium on Lithium Genetics (ConLiGen) Report}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {6}, doi = {10.1371/journal.pone.0065636}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130938}, pages = {e65636}, year = {2013}, abstract = {Objective: The assessment of response to lithium maintenance treatment in bipolar disorder (BD) is complicated by variable length of treatment, unpredictable clinical course, and often inconsistent compliance. Prospective and retrospective methods of assessment of lithium response have been proposed in the literature. In this study we report the key phenotypic measures of the "Retrospective Criteria of Long-Term Treatment Response in Research Subjects with Bipolar Disorder" scale currently used in the Consortium on Lithium Genetics (ConLiGen) study. Materials and Methods: Twenty-nine ConLiGen sites took part in a two-stage case-vignette rating procedure to examine inter-rater agreement [Kappa (\(\kappa\))] and reliability [intra-class correlation coefficient (ICC)] of lithium response. Annotated first-round vignettes and rating guidelines were circulated to expert research clinicians for training purposes between the two stages. Further, we analyzed the distributional properties of the treatment response scores available for 1,308 patients using mixture modeling. Results: Substantial and moderate agreement was shown across sites in the first and second sets of vignettes (\(\kappa\) = 0.66 and \(\kappa\) = 0.54, respectively), without significant improvement from training. However, definition of response using the A score as a quantitative trait and selecting cases with B criteria of 4 or less showed an improvement between the two stages (\(ICC_1 = 0.71\) and \(ICC_2 = 0.75\), respectively). Mixture modeling of score distribution indicated three subpopulations (full responders, partial responders, non responders). Conclusions: We identified two definitions of lithium response, one dichotomous and the other continuous, with moderate to substantial inter-rater agreement and reliability. Accurate phenotypic measurement of lithium response is crucial for the ongoing ConLiGen pharmacogenomic study.}, language = {en} } @phdthesis{Schneider2004, author = {Schneider, Sebastian}, title = {Karpale Bandverletzungen - Vergleich der direkten MR-Arthrographie mit der diagnostischen Arthroskopie unter Ber{\"u}cksichtigung von Partialdefekten des skapholun{\"a}ren Bandes, des lunatotriquetralen Bandes sowie des TFCC}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7970}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Evaluation von Defekten des triangul{\"a}ren fibrokartilagin{\"a}ren Komplexes (TFCC) und der intrinsischen B{\"a}nder des Handgelenkes mit der direkten MR-Arthrographie im Vergleich zur diagnostischen Arthroskopie unter besonderer Ber{\"u}cksichtigung von Partialdefekten. Material und Methoden: 75 direkte MR-Arthrographien des Handgelenkes (intraartikul{\"a}re Injektion eines Gemisches aus Gadoliniumchelaten und Iotrolan) wurden von zwei erfahrenen Radiologen im Konsens ausgewertet. Es wurden T1-gewichtete Spin-Echo(SE)-Sequenzen in frontaler und sagittaler sowie Fast low angle shot (FLASH) 3D-Sequenzen in frontaler Schichtung akquiriert. L{\"a}sionen des skapholun{\"a}ren Bandes wurden entsprechend den Leitlinien der Deutschen Gesellschaft f{\"u}r Handchirurgie (DGH), L{\"a}sionen des lunatotriquetralen Bandes nach Hempfling, L{\"a}sionen des TFCC nach Palmer eingeteilt. Anschließend wurden die Befunde mit der Arthroskopie als Referenzstandard korreliert. Ergebnisse: F{\"u}r die Verletzungen der intrinsischen B{\"a}nder und des TFCC waren die Sensitivit{\"a}ten und Spezifit{\"a}ten f{\"u}r Komplettrupturen 96\% und 99,6\% (T1-SE) bzw. 92\% und 100\% (FLASH 3D), f{\"u}r Partialdefekte 68,1\% und 93,3\% (T1-SE) bzw. 63\% und 96,1\% (FLASH 3D). Die T1-SE-Sequenz eignete sich f{\"u}r die Einsch{\"a}tzung skapholun{\"a}rer Banddefekte besser als die FLASH 3D-Sequenz (p < 0,05). F{\"u}r Partialdefekte das skapholun{\"a}ren Bandes wurde mit der T1-SE-Sequenz eine Sensitivit{\"a}t von 83,3\%, mit der FLASH 3D-Sequenz von 64,7\% erreicht. Schlussfolgerung: Die direkte MR-Arthrographie ist bei der Einsch{\"a}tzung von Komplettrupturen der intrinsischen B{\"a}nder und des TFCC der diagnostischen Arthroskopie gleichwertig. Mit der T1-SE-Sequenz sind Partialdefekte des skapholun{\"a}ren Bandes im Vergleich zur Arthroskopie mit ausreichender Sicherheit erkennbar. Die T1-SE-Sequenz war hierf{\"u}r der FLASH 3D-Sequenz {\"u}berlegen (p < 0,05) und sollte bei der Einsch{\"a}tzung skapholun{\"a}rer Partialdefekte bevorzugt werden. Die Einsch{\"a}tzung des lunatotriquetralen Bandes gelingt nicht zuverl{\"a}ssig.}, language = {de} }