Single-frequency lasers' linewidth elegantly characterized with Sigmoid functions of observation time

Linewidth is the most important parameter for characterizing the coherence properties of a single-frequency laser, but unfortunately only the natural linewidth representing the contributions of the spontaneous emission or quantum noise can be described with an analytical expression known as the Schawlow-Townes-Henry formula. To the best of authors' knowledge, no analytical expression is formulized after 63 years since laser's invention for characterizing the effective linewidth of a single-frequency laser including the linewidth broadening caused by the flicker noises, which strongly depends on the measurement duration and is much larger than the natural linewidth. By carefully measuring the instantaneous frequency fluctuations of multiple commercial single-frequency lasers using a self-built optical frequency analyzer with ultra-high resolution and speed to obtain their linewidths with our time domain statistical analysis method, we discover and validate that the laser linewidths can be expressed as one or more Sigmoid functions of observation time. Not only the simple Sigmoid linewidth expression provides clear linewidth information of the laser, but also better understanding of the physical origins affecting the laser linewidths, which will benefit a large number of applications ranging from coherent distributed sensing to gravitational wave detection and therefore is worthy to be widely adopted to fully and elegantly characterize the linewidths of single-frequency lasers.Comment: 27 pages, 16 figures, 1 table, research articl

MOON: MapReduce On Opportunistic eNvironments

Abstract—MapReduce offers a flexible programming model for processing and generating large data sets on dedicated resources, where only a small fraction of such resources are every unavailable at any given time. In contrast, when MapReduce is run on volunteer computing systems, which opportunistically harness idle desktop computers via frameworks like Condor, it results in poor performance due to the volatility of the resources, in particular, the high rate of node unavailability. Specifically, the data and task replication scheme adopted by existing MapReduce implementations is woefully inadequate for resources with high unavailability. To address this, we propose MOON, short for MapReduce On Opportunistic eNvironments. MOON extends Hadoop, an open-source implementation of MapReduce, with adaptive task and data scheduling algorithms in order to offer reliable MapReduce services on a hybrid resource architecture, where volunteer computing systems are supplemented by a small set of dedicated nodes. The adaptive task and data scheduling algorithms in MOON distinguish between (1) different types of MapReduce data and (2) different types of node outages in order to strategically place tasks and data on both volatile and dedicated nodes. Our tests demonstrate that MOON can deliver a 3-fold performance improvement to Hadoop in volatile, volunteer computing environments

Nonlocal delayed-choice experiments with entangled photons

Obwohl Störungen ist untrennbar mit einer klassisch-Welle Phänomen, ist das Superpositionsprinzip, die Störungen zu Grunde liegt im Herzen der Quantenphysik. Feynman genannten Störungen als wirklich "das einzige Geheimnis" der Quantenphysik [FLS63].Offensichtlich Störungen konfrontiert uns mit einigen grundlegenden Fragen der Auslegung der Quantenphysik. Trotz seiner langen Geschichte geht zurück auf Thomas Young zu Beginn des 19. Jahrhunderts, Quanten interferenzoptisch noch Herausforderungen unseres Verständnisses.Mit der Entwicklung der experimentellen Techniken zur schnellen und empfindlichen Messungen von Licht, ist es möglich geworden durchzuführen viele der gedankenexperiments deren Interpretationen wurden weithin im Laufe der Entwicklung der Quantenphysik [Whe84, SD82, SEW91, Per00] diskutiert. Die vorliegende Arbeit enthält die experimentelle Realisierung von drei verschiedenen gedankenexperiments: ein nicht-lokales Quantenradierer, Zwei-Photonen-Hong-Ou-Mandel Interferenz unter Bedingungen und Einstein Lokalität verzögerten Wahl Verschränkung Swapping. Der Zweck dieser Arbeit ist es, experimentell zeigen einige der counter-intuitive Features der Quantenphysik über verschiedene Quantenphänomene. Sie unterstreichen deutlich die unterschiedlichen Vorstellungen von Raum und Zeit, zwischen klassischer und Quantenphysik. Solche Augenbrauen-Anhebung Eigenschaften von Raum und Zeit in der Quantenphysik wurden "als eines der faszinierendsten Effekte in der Quantenmechanik beschrieben "[AZ05]. Die "spukhafte Fernwirkung" (in Einsteins Worten) eines verschränkten Systems ist in auffälliger Weise von Scully et al illustriert. 'S Quantenradierer [SD82, SEW91], in denen man wählen, ob oder nicht zu löschen, die kann- Pfadinformation eines Teilchens durch Ausführen einer geeigneten Messungen auf ein anderes Teilchen mit verschränkten es. Da die Quantenmechanik ist gleichgültig gegen die räumliche und zeitliche Reihenfolge der Messungen an verschränkten Teilchen, können Sie diese Auswahl beliebig verschoben werden und räumlich in Bezug auf das störende Ereignis des ersten Teilchens voneinander getrennt (siehe Kapitel 3). Wheeler dargestellten Grundsatz der Komplementarität mit Einzel-Photonen-Interferenz in einer verzögerten Wahl Gedankenexperiment [Whe84]. Im Gegensatz zur Einzel-Photonen-Interferenz (Störung zweiter Ordnung), die ein klassisches Analogon hat, ergibt sich Zwei-Photonen-Hong-Ou-Mandel (HOM) Störungen (Interferenzen vierter Ordnung) von der bosonischen Natur der Photonen und die unitäre Transformation von einem Strahlteiler. Wie von Mandel betonte, "diese Vorhersage hat kein klassisches Analogon, und seine Bestätigung wäre ein interessanter Test der Quantentheorie des elektromagnetischen Feldes dar" [Man83, Man99]. Die Realisierung der Zwei-Photonen-HOM Interferenzversuch unter Einstein Lokalität Bedingungen (dh die relevanten Ereignisse sind relativistisch space-like getrennt) deutlich erweitert Wheeler's verzögerten Wahl Gedankenexperiment Konzept (siehe 4.2). In der Quantenphysik, können die Ereignisse beeinflussen, wie wir die Daten in der Vergangenheit erzielten interpretieren. Dieses Phänomen wird in illustrierten Peres 'delayed-Wahl Verstrickung-Swapping Gedankenexperiment [Per00], wo man wählt, ob oder nicht zu verstricken zwei Teilchen, nachdem sie erkannt wurden und nicht einmal mehr zu existieren.Die Ergebnisse zeigen, dass die zeitliche Reihenfolge der Wahl und die Messung Veranstaltungen in einem solchen Experiment irrelevant ist, wie vorhergesagt durch die Quantenphysik (siehe 4.3). Die wichtigsten Merkmale der Experimente in dieser Arbeit vorgestellt werden: (1) High-Speed-elektro-optische Modulatoren von einem Quanten-Zufallszahlen-Generator, die zusammen ermöglichen es uns, schnell umzusetzen und zufällige Messung der Photonen gesteuert. (2) Die räumliche und zeitliche Beziehungen der verschiedenen Veranstaltungen, die im Raum-Zeit-Diagramme dargestellt werden können, sind in geeigneter Weise angeordnet, um nicht-klassischen und counter-intuitive Features der Quantenphysik zeigen.Although interference is intrinsically a classical-wave phenomenon, the superposition principle which underlies interference is at the heart of quantum physics. Feynman referred to interference as really "the only mystery" of quantum physics [FLS63]. Clearly interference confronts us with some basic questions of the interpretation of quantum physics. Despite its long history, going back to Thomas Young at the beginning of the 19th century, quantum optical interference still challenges our understanding. With the development of experimental techniques for fast and sensitive measurements of light, it has become possible to carry out many of the gedankenexperiments whose interpretations were widely debated in the course of the development of quantum physics [Whe84, SD82, SEW91, Per00]. The present thesis contains the experimental realization of three different gedankenexperiments: a non-local quantum eraser, two-photon Hong-Ou-Mandel interference under Einstein locality conditions and delayed-choice entanglement swapping. The purpose of this thesis is to experimentally demonstrate some of the counter-intuitive features of quantum physics via various quantum phenomena. They dramatically underscore the different conceptions of space and time between classical and quantum physics. Such eyebrow-raising features of space and time in quantum physics have been described "as one of the most intriguing effects in quantum mechanics" [AZ05]. The "spooky action at a distance" (in Einstein's words) of an entangled system is illustrated in a striking way by Scully et al.'s quantum eraser [SD82, SEW91], in which one can choose whether or not to erase which-path information of one particle by performing suitable measurements on another particle entangled with it. Since quantum mechanics is indifferent to the spatial and temporal order of measurements on entangled particles, this choice can be arbitrarily delayed and spatially separated with respect to the interfering event of the first particle (see Chapter 3). Wheeler illustrated the complementarity principle with single-photon interference in a delayed-choice gedankenexperiment [Whe84]. In contrast with single-photon interference (second-order interference), which has a classical analogue, two-photon Hong-Ou-Mandel (HOM) interference (fourth-order interference) stems from the bosonic nature of the photons and the unitary transformation of a beam splitter. As stressed by Mandel "this prediction has no classical analogue, and its confirmation would represent an interesting test of the quantum theory of the electromagnetic field" [Man83, Man99]. The realization of the two-photon HOM interference experiment under Einstein locality conditions (i.e. the relevant events are relativistically space-like separated) significantly extends Wheeler's delayed-choice gedankenexperiment's concept (see 4.2). In quantum physics, present events can affect how we interpret the data obtained in the past. This phenomenon is illustrated in Peres' delayed-choice entanglement-swapping gedankenexperiment [Per00], where one chooses whether or not to entangle two particles after they have been detected and don't even exist anymore. The results show that the temporal order of the choice and the measurement events in such an experiment is irrelevant, as predicted by quantum physics (see 4.3). The important features of the experiments presented in this thesis are: (1) High-speed electro-optical modulators controlled by a quantum random number generator, which together allow us to implement fast and random measurements of the photons. (2) The spatial and temporal relations of various events, which may be illustrated in space-time diagrams, are appropriately arranged to show non-classical and counter-intuitive features of quantum physics

Understand Data Preprocessing for Effective End-to-End Training of Deep Neural Networks

In this paper, we primarily focus on understanding the data preprocessing pipeline for DNN Training in the public cloud. First, we run experiments to test the performance implications of the two major data preprocessing methods using either raw data or record files. The preliminary results show that data preprocessing is a clear bottleneck, even with the most efficient software and hardware configuration enabled by NVIDIA DALI, a high-optimized data preprocessing library. Second, we identify the potential causes, exercise a variety of optimization methods, and present their pros and cons. We hope this work will shed light on the new co-design of ``data storage, loading pipeline'' and ``training framework'' and flexible resource configurations between them so that the resources can be fully exploited and performance can be maximized

Complex Dynamics in Nonlinear Triopoly Market with Different Expectations

A dynamic triopoly game characterized by firms with different expectations is modeled by three-dimensional nonlinear difference equations, where the market has quadratic inverse demand function and the firm possesses cubic total cost function. The local stability of Nash equilibrium is studied. Numerical simulations are presented to show that the triopoly game model behaves chaotically with the variation of the parameters. We obtain the fractal dimension of the strange attractor, bifurcation diagrams, and Lyapunov exponents of the system

Genome-Wide Association Study for Plant Height and Grain Yield in Rice under Contrasting Moisture Regimes

Drought is one of the vitally critical environmental stresses affecting both growth and yield potential in rice. Drought resistance is a complicated quantitative trait that is regulated by numerous small effect loci and hundreds of genes controlling various morphological and physiological responses to drought. For this study, 270 rice landraces and cultivars were analyzed for their drought resistance. This was done via determination of changes in plant height and grain yield under contrasting water regimes, followed by detailed identification of the underlying genetic architecture via genome-wide association study (GWAS). We controlled population structure by setting top two eigenvectors and combining kinship matrix for GWAS in this study. Eighteen, five, and six associated loci were identified for plant height, grain yield per plant, and drought resistant coefficient, respectively. Nine known functional genes were identified, including five for plant height (OsGA2ox3, OsGH3-2, sd-1, OsGNA1 and OsSAP11/OsDOG), two for grain yield per plant (OsCYP51G3 and OsRRMh) and two for drought resistant coefficient (OsPYL2 and OsGA2ox9), implying very reliable results. A previous study reported OsGNA1 to regulate root development, but this study reports additional controlling of both plant height and root length. Moreover, OsRLK5 is a new drought resistant candidate gene discovered in this study. OsRLK5 mutants showed faster water loss rates in detached leaves. This gene plays an important role in the positive regulation of yield-related traits under drought conditions. We furthermore discovered several new loci contributing to the three investigated traits (plant height, grain yield, and drought resistance). These associated loci and genes significantly improve our knowledge of the genetic control of these traits in rice. In addition, many drought resistant cultivars screened in this study can be used as parental genotypes to improve drought resistance of rice by molecular breeding