連続変数を用いた二光子干渉の観測

Two-photon interference is highly important, fundamental, and indefeasible features of quantum mechanics. It has numerous applications in production of quantum state, which is useful in quantum communications, quantum information processing, and quantum metrology. In this thesis, we experimentally observed a two-photon interference between a squeezed vacuum state and a coherent state with continuous variables by homodyne detection for the first time. The photon anti-bunching effect and bunching effect of the measured field were investigated by calculating the second-order correlation function from the measured quadrature amplitudes, which were obtained by two homodyne detection systems. This provides another method to observe two-photon interference, and the method has the following merits: First, we gave a new method to calculate the second-order correlation function. It provides a link to close the gap between discrete variables and continuous variables in the field of quantum optics. Then, we experimentally observed two-photon interference (particle property) by measuring amplitude quadratures (wave property) of the light field. In other words, we used a wave method to investigate the particle property of light. It may give another evidence to show the wave-particle duality of light. At last, we experimentally observed the two-photon interference at two sideband frequencies of laser light. As applications, it opens a new method to generate a single-photon frequency comb and leads to potential applications in multi-channel quantum communications technology. The detail of this thesis is included as follows: 1. We experimentally generated a squeezed vacuum state from a below threshold optical parametric amplifier (OPA) with periodically poled KTiOPO4 (PPKTP) crystal. The OPA could be controlled so as to de-amplify or amplify the injection beam by choosing the relative phase between pump and injection beams. This ensures to produce the amplitude quadrature or phase quadrature squeezed state with the squeezing level of -1 dB and anti-squeezing of 1.7 dB in the range of 5 MHz to the cavity linewidth of 35 MHz. 2. We reconstructed the Winger function of generated states by homodyne tomography. Using homodyne detection, we measured a set of probability densities for the quadrature amplitudes of the generated states. These histograms were inverted using inverse Radon transform to reconstruct the Winger distribution which showed the fluctuation of the light fields in phase space. It intuitively characterizes the generated vacuum states, coherent states, squeezed vacuum states and displaced squeezed states in our experiment. 3. We experimentally observed a continuous-wave two-photon interference between a squeezed vacuum state from an OPA and a weak coherent state on a beam splitter by measuring the second-order correlation function with the homodyne detection system. A second-order correlation function of g(2)(0) = 0:811 was also obtained when the phase squeezed vacuum state is employed.　量子光学および量子情報の実験研究については大きくわけて(1)離散変数と(2)連続変数の二つである。前者には光の粒子性を注目し、識別できない光子間の量子干渉を根幹として行う。また、後者は光(電磁場)の波動性を注目し、電場の二つ直交位相振幅を観測量として扱う。二つ分野分けますが、いずれもいろいろな量子もつれの生成するのは、量子光学と量子情報においてとても重要で、量子情報提案を実現することのキーとなる。その中で我々は光の粒子性に注目し,その特徴の一つである二光子干渉を観測することを目指している.従来,二光子干渉はアバランシェフォトダイオード(APD)による光子数を直接的に評価する離散的な測定が良く報告されてきた.一方,ホモダイン検出器を用いて連続変数である直交位相振幅のデータから光子数の情報を評価する方法は,新たな手法として期待される.本研究は、連続変数を用いて位相空間における奇妙な二光子干渉現象を実験的に検証することを目的としている。　光源として波長1064 nmで連続波(CW)のNd:YAGレーザーを使用した.光源からの光は第二高調波発生(SHG)と雑音低減のためのモードクリーナー共振器(MCC)に入射するため, 2つに分割した. SHGからの532 nmの光はポンプ光として用い,光パラメトリック増幅器(OPA)に入射し,真空スクイーズド状態を生成した. MCCからの光はseed光,コヒーレント光,ローカルオシレーター(LO)光として用いるため3つに分割した.コヒーレント光は電気光学変調器(EOM)による振幅変調(AM)もしくは位相変調(PM)によって生成した.真空スクイーズド状態とコヒーレント光を95%反射ミラーで干渉させることでディスプレイススクイーズド状態の生成を実現した.ディスプレイススクイーズド状態はEOMによるAM方式, PM式によってそれぞれ振幅スクイーズド状態,位相スクイーズド状態となる.それぞれのディスプレイススクイーズド状態が正しく生成されているかはホモダイントモグラフィを用いてWigner関数を構築することによって確認した. 二光子干渉の観測では,位相スクイーズド状態,振幅スクイーズド状態について二次強度相関g(2)(0)を測定した.位相クイーズド状態では常にg(2)(0)>1となるバンチング状態となり,二光子確率が増大していることが観測された,一方,振幅スクイーズド状態の測定では最小値がg(2)(0) =0:810:03と1を下回るアンチバンチング状態となり二光子確率の低減を観測した.この結果から,直交位相振幅を測定対象としてホモダイン検出器を使用し,二光子干渉が観測出来ていることが示された. 更に今後の光子数確率の測定に向け,実際に二光子確率がどのように変化していると考えられるのか,測定のためにはどのような光源が必要となるかを考察した.電気通信大学201

Verifizierbare Entwicklung eines satellitenbasierten Zugsicherungssystems mit Petrinetzen

Nowadays model-based techniques are widely used in system design and development, especially for safety-critical systems such as train control systems. Given a design model, executable codes could be generated automatically from the model following certain transformation rules. A high-quality model of a system provides a good understanding, a favourable structure, a reasonable scale and abstraction level as well as realistic behaviours with respect to the concurrent operation of independent subsystems. Motivated by this principle, a first Coloured Petri Net (CPN) model of a satellite-based train control system (SatZB) with the capability of continuous simulation is developed employing the BASYSNET method which adopts Petri nets as the means of description during the whole development process. After establishing the system model, the verification tasks are identified based on the hazard analysis of the train control system. To verify the identified tasks for quality assurance, verification by means of simulation, formal analysis and testing is carried out considering the four representing system properties: function, state, structure and behaviour. For structural analysis, the concept of open nets is proposed to check the reproducibility of empty markings of scenario nets, the existence of dead transitions in the scenario nets, and the terminating states of the scenario nets. The system behaviour, in which states are involved, is investigated by reachability analysis. Unlike the conventional method of reachability analysis by calculating the state space of the Petri net, techniques based on Petri net unfoldings are introduced in this thesis. As to the functional verification, two model-based test generation techniques, i.e., CPN-based and SPENAT (Safe Place Transition Nets with Attributes)-based techniques, are presented. In this thesis, the proposed methods are exemplified by the application to the on-board module of SatZB model. According to the verification results, no errors were found in the module. Therefore, the confidence in the quality of the on-board module has been significantly increased.Heutzutage werden in zahlreichen Anwendungen modellbasierte Techniken zur Systementwicklung, insbesondere für sicherheitskritische Systeme wie Eisenbahnleit- und -sicherungssysteme, verwendet. Aus einem Design Modell kann dabei ausführbarer Code automatisch nach bestimmten Transformationsregeln generiert werden. Ein hochwertiges Modell des Systems bietet für die Entwicklung ein gutes Verständnis, eine günstige Struktur, eine angemessene Größenordnung und Abstraktionsebene als auch realistische Verhaltensweisen in Bezug auf den gleichzeitigen Betrieb von unabhängigen Subsystemen. Motiviert von dieses Prinzip wird ein erstes Farbige Petri-Netz (CPN)-Modell eines satellitenbasierten Zugsicherungssystem (SatZB) unter Verwendung der BASYSNET Methode entwickelt, der Petri-Netze als Beschreibungsmittel während des gesamten Entwicklungsprozesses nutzt. Dieses Modell bietet die Möglichkeit zur kontinuierlichen Simulation des Systemverhaltens. Nach der Erstellung des Systemmodells werden die Verifikationsaufgaben auf der Grundlage der Gefährdungsanalyse des Zugsicherungssystems identifiziert. Die abgeleiteten Bedingungen werden zur Qualitätssicherung durch Simulation, formale Analysen und Tests unter Berücksichtigung der vier Systemeigenschaften (Funktion, Zustand, Struktur und Verhalten) verifiziert. Für die Strukturanalyse wird das Konzept der offenen Netzen vorgeschlagen, um die Reproduzierbarkeit der leeren Markierungen der Szenario-Netze, die Existenz der Toten Transitionen in den Szenario-Netze, und die Abschluss Zustände der Szenario-Netze zu prüfen. Das Systemverhalten wird dabei durch Zustände beschrieben und durch eine Erreichbarkeitsanalyse untersucht. Im Gegensatz zu der konventionellen Methode, welche die Erreichbarkeit durch die Berechnung des Zustandsraums des Petri-Netzes analysiert, werden in dieser Arbeit Techniken auf Basis von Petri-Netz-Entfaltung eingeführt. Für die funktionale Verifikation werden zwei modellbasierte Testgenerierungstechniken, eine CPN-basierte und eine SPENAT (Sicheres Petrinetz mit Attributen)-basierte, vorgestellt. In dieser Arbeit werden die vorgeschlagenen Methoden durch die Anwendung auf das On-Board-Modul des SatZB-Modells veranschaulicht. Dabei wurden nach dem Abschluss der Prüfungen keine Fehler im Modul gefunden, wodurch das Vertrauen in die Qualität des On-Board-Moduls deutlich erhöht wurde

Geniposide Alleviates Glucocorticoid-Induced Inhibition of Osteogenic Differentiation in MC3T3-E1 Cells by ERK Pathway

Glucocorticoid (GC) therapy is the leading cause of secondary osteoporosis and the therapeutic and preventative drugs for GC-induced osteoporosis are limited. In this study, we investigated the protective effects of geniposide on dexamethasone (DEX)-induced osteogenic inhibition in MC3T3-E1 cells. The results showed that there was no obvious toxicity on MC3T3-E1 cells when geniposide was used at the doses ranging from 1 to 75 μM. In DEX-treated MC3T3-E1 cells, geniposide promoted the alkaline phosphatase (ALP) activity and the mineralization. In addition, geniposide also significantly increased the mRNA and protein expression of osteopontin (OPN), Runt-related transcription factor 2 (Runx2), and Osterix (Osx) in DEX-treated MC3T3-E1 cells. Furthermore, geniposide activated ERK pathway in DEX-treated MC3T3-E1 cells. The ERK activation inhibitor U0126 and glucagon-like peptide-1 (GLP-1) receptor antagonist exendin 9-39 abolished the geniposide-induced activation of ERK and inhibited the protective effect of geniposide. Taken together, our study revealed that geniposide alleviated GC-induced osteogenic suppression in MC3T3-E1 cells. The effect of geniposide was at least partially associated with activating ERK signaling pathway via GLP-1 receptor. Geniposide might be a potential therapeutic agent for GC-induced osteoporosis

連続変数を用いた二光子干渉の観測

電気通信大学201

Generation of Long-Term Stable Squeezed Vacuum States Using Dither-Locking Technique

We report the generation of long-term stable squeezed vacuum states at 1064 nm using a degenerate optical parametric amplifier (DOPA) with a periodically poled KTiOPO4 crystal (PPKTP). The OPA is pumped by a 532 nm light produced by frequency doubling the fundamental light with a bow-tie enhancement second harmonic generator (SHG). When the DOPA and relative phases are locked using a dither-locking method, the squeezed vacuum states are stably measured over 2 h at 11 MHz. The highly compact and simple squeezed light source is suitable for applications in quantum optics experiments

Efficacy and Safety of the Injection of the Traditional Chinese Medicine Puerarin for the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review and Meta-Analysis of 53 Randomized Controlled Trials

Objective. The injection of the traditional Chinese patent medicine puerarin has been widely used in the treatment of various diseases such as angina pectoris or ischemic stroke. We aim to evaluate the efficacy and safety of puerarin injection for the treatment of diabetic peripheral neuropathy (DPN). Methods. A systematic literature search was performed in seven medical databases from their inception until June 2017. 53 studies with RCTs, totaling 3284 patients, were included in this meta-analysis. The included studies were assessed by the Cochrane risk of bias and analyzed by Review Manager 5.3 software. Results. The meta-analysis showed that puerarin injection for the treatment of DPN was significantly better compared with the control group in terms of the total effective rate. The result showed that puerarin injection for the treatment of DPN can significantly increase the probability of sensory nerve conduction velocity (SNCV) and motor nerve conduction velocity (MNCV) of the median and peroneal nerves. Conclusions. This meta-analysis demonstrated that puerarin injection may be more effective and safe for the treatment of DPN. However, further and higher quality RCTs are required to prove its efficacy and provide meaningful evidence for clinical treatment due to the poor methodological quality

APF-IRRT*: An Improved Informed Rapidly-Exploring Random Trees-Star Algorithm by Introducing Artificial Potential Field Method for Mobile Robot Path Planning

An Informed RRT* (IRRT*) algorithm is one of the optimized versions of a Rapidly-exploring Random Trees (RRT) algorithm which finds near-optimal solutions faster than RRT and RRT* algorithms by restricting the search area to an ellipsoidal subset of the state space. However, IRRT* algorithm has the disadvantage of randomness of sampling and a non-real time process, which has a negative impact on the convergence rate and search efficiency in path planning applications. In this paper, we report a hybrid algorithm by combining the Artificial Potential Field Method (APF) with an IRRT* algorithm for mobile robot path planning. By introducing the virtual force field of APF into the search tree expansion stage of the IRRT* algorithm, the guidance of the algorithm increases, which greatly improves the convergence rate and search efficiency of the IRRT* algorithm. The proposed algorithm was validated in simulations and proven to be superior to some other RRT-based algorithms in search time and path length. It also was performed in a real robotic platform, which shows that the proposed algorithm can be well executed in real scenarios

miR-365 Ameliorates Dexamethasone-Induced Suppression of Osteogenesis in MC3T3-E1 Cells by Targeting HDAC4

Glucocorticoid administration is the leading cause of secondary osteoporosis. In this study, we tested the hypotheses that histone deacetylase 4 (HDAC4) is associated with glucocorticoid-induced bone loss and that HDAC4 dependent bone loss can be ameliorated by miRNA-365. Our previous studies showed that miR-365 mediates mechanical stimulation of chondrocyte proliferation and differentiation by targeting HDAC4. However, it is not clear whether miR-365 has an effect on glucocorticoid-induced osteoporosis. We have shown that, in MC3T3-E1 osteoblasts, dexamethasone (DEX) treatment decreased the expression of miR-365, which is accompanied by the decrease of cell viability in a dose-dependent manner. Transfection of miR-365 ameliorated DEX-induced inhibition of MC3T3-E1 cell viability and alkaline phosphatase activity, and attenuated the suppressive effect of DEX on runt-related transcription factor 2 (Runx2), osteopontin (OPN), and collagen 1a1 (Col1a1) osteogenic gene expression. In addition, miR-365 decreased the expression of HDAC4 mRNA and protein by direct targeting the 3′-untranslated regions (3′-UTR) of HDAC4 mRNA in osteoblasts. MiR-365 increased Runx2 expression and such stimulatory effect could be reversed by HDAC4 over-expression in osteoblasts. Collectively, our findings indicate that miR-365 ameliorates DEX-induced suppression of cell viability and osteogenesis by regulating the expression of HDAC4 in osteoblasts, suggesting miR-365 might be a novel therapeutic agent for treatment of glucocorticoid-induced osteoporosis

Observation of two-photon interference with continuous variables by homodyne detection

We experimentally observed a two-photon interference between a squeezed vacuum state from an optical parametric amplifier and a weak coherent state on a beam splitter with continuous variables. The photon statistics properties of the mixed field were investigated by calculating the correlations among four permutations of measured quadratures components, which were obtained by two homodyne detection systems. This also means that the two-photon interference occurred at analysis frequency differing from the previous two-photon interference reports. The nonclassical effect of photon anti-bunching occurred when an amplitude squeezed vacuum state acted as one of interference sources. On the other hand, the photon bunching effect appeared when a phase squeezed vacuum state was employed