3,176 research outputs found

    Experimental study of optimal measurements for quantum state tomography

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    Quantum tomography is a critically important tool to evaluate quantum hardware, making it essential to develop optimized measurement strategies that are both accurate and efficient. We compare a variety of strategies using nearly pure test states. Those that are informationally complete for all states are found to be accurate and reliable even in the presence of errors in the measurements themselves, while those designed to be complete only for pure states are far more efficient but highly sensitive to such errors. Our results highlight the unavoidable tradeoffs inherent to quantum tomography.Comment: 5 pages, 3 figure

    P.O.S. coverage index: Measurement procedure of the relationship between ball and hand

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    Este trabajo diseña un novedoso procedimiento de medición que relaciona el tamaño de la mano y el tamaño del balón. Se detalla este procedimiento ideado para la determinación del “Índice de Cobertura de la Mano Porras, Oliver, Sosa” (I.C.M.P.O.S.) sobre el balón. A partir de tres medidas obtenidas de la mano dominante de los deportistas con la mano en máxima apertura tomadas sobre un plano, calcularemos sus coordenadas en el espacio, y las aplicaremos sobre la esfera del balón. Posteriormente, a través de una fórmula, y teniendo en cuenta el valor central de la medida de la circunferencia del balón del deporte y de la categoría deportiva correspondiente, podremos conocer el Índice de Cobertura de la mano del deportista sobre el balón, o cantidad del balón que un deportista es capaz de abarcar con su mano completamente abierta respecto a la media esfera del balón de su categoría deportivaThis paper designs a novel measurement procedure that relates the size of the hand and the size of the ball. This procedure was devised in order to determine the "Hand Coverage Index of Porras, Oliver, Sosa" (H.C.I.P.O.S.) on the ball. Using three measurements obtained from the dominant hand of athletes with the hand on its maximum aperture taken on a flat plane, we calculated their coordinates in space, and their applications on the sphere of the ball. Subsequently, through a formula, and taking into account the central value of the measurement of the circumference of the ball and the corresponding sport category, we will be able to know the Hand Coverage Index of the athlete over the ball, or the surface of the ball that an athlete is able to cover with his fully open hand with respect to the the sphere of the ball of his sport categor

    Goalkeeper-field player in situations of offensive numerical inferiority in handball: Penalty or advantage?

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    El objetivo principal fue analizar el resultado final de la acción ofensiva entre los equipos que utilizan, o no, el portero-jugador en situaciones de inferioridad numérica ofensiva en balonmano. Los objetivos secundarios se centran en analizar cómo es la utilización y el comportamiento del portero-jugador y su relación con el resultado final ofensivo y la posterior acción con respecto al contraataque del equipo contrario. Se analizaron las actas oficiales de 86 partidos del 22º Campeonato del Mundo de Balonmano Femenino (Dinamarca 2015) y se realizó el visionado, análisis y registro de las 927 situaciones de inferioridad numérica ofensiva, así como el estudio estadístico pertinente con SPSS v.24. Los resultados demuestran que el uso del recurso táctico o estratégico del portero-jugador favorece la obtención de gol en situaciones de inferioridad numérica ofensiva y no penaliza al equipo que lo utiliza, al no existir diferencia significativa en la probabilidad de recibir gol en contraataqueThe main goal was to analyze the end results in offensive actions between teams that do or do not employ the goalkeeper-field player in situations of offensive numerical inferiority in handball. The secondary objectives focus on analyzing the use and behavior of the goalkeeper-field player, as well as its role in the final offensive result and following actions in terms of the opposing team’s counterattack. 86 official match reports from the 22nd Women's Handball World Championship (Denmark 2015) were analyzed, and the viewing, analysis and registration of the 927 situations of offensive numerical inferiority were carried out, as well as the pertinent statistical study with SPSS v.24. The results show that the tactical or strategic use of the goalkeeper-field player favors goal scoring in situations of offensive numerical inferiority and does not punish the team which employs it, since there’s no significant difference in the probability of conceding a goal in counterattac

    Quantum state tomography by continuous measurement and compressed sensing

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    The need to perform quantum state tomography on ever larger systems has spurred a search for methods that yield good estimates from incomplete data. We study the performance of compressed sensing (CS) and least squares (LS) estimators in a fast protocol based on continuous measurement on an ensemble of cesium atomic spins. Both efficiently reconstruct nearly pure states in the 16-dimensional ground manifold, reaching average fidelities FCS = 0.92 and FLS = 0.88 using similar amounts of incomplete data. Surprisingly, the main advantage of CS in our protocol is an increased robustness to experimental imperfections

    Convolution, aggregation and attention based deep neural networks for accelerating simulations in mechanics

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    Deep learning surrogate models are being increasingly used in accelerating scientific simulations as a replacement for costly conventional numerical techniques. However, their use remains a significant challenge when dealing with real-world complex examples. In this work, we demonstrate three types of neural network architectures for efficient learning of highly non-linear deformations of solid bodies. The first two architectures are based on the recently proposed CNN U-NET and MAgNET (graph U-NET) frameworks which have shown promising performance for learning on mesh-based data. The third architecture is Perceiver IO, a very recent architecture that belongs to the family of attention-based neural networks--a class that has revolutionised diverse engineering fields and is still unexplored in computational mechanics. We study and compare the performance of all three networks on two benchmark examples, and show their capabilities to accurately predict the non-linear mechanical responses of soft bodies

    Decision-making in school-age sport measured through a digital tool.

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    El objetivo de este estudio ha sido doble. Por un lado, diseñar y crear un software de evaluación de toma de decisiones en edad escolar, en base a aspectos espacio-temporales, contextualizado en voleibol, denominado “Juego Interactivo de Voleibol”. Por otro lado, analizar y establecer su fiabilidad y validez. El software diseñado se aplicó a una muestra de 132 escolares (64 niños y 68 niñas) de entre 10 y 13 años, de los centros educativos públicos de Educación Primaria y Secundaria de las localidades sevillanas de Arahal y Paradas (España). Para determinar la fiabilidad se estudió la consistencia interna a través del coeficiente alfa de Cronbach. Para calcular el número óptimo de repeticiones se utilizó el Coeficiente de Correlación Intraclase. La validez se comprobó en base a la evaluación de un grupo de 5 expertos. Los resultados indicaron que este nuevo software de evaluación alcanza altos niveles de fiablidad y validezThe aim of this study was twofold. On the one hand, the design and creation of an evaluation software for decision-making in school-age children based on spatial-temporal aspects in the context of volleyball called ‘Interactive Volleyball Game’. On the other hand, the analysis and establishment of its reliability and validity. The designed software was applied to a sample of 132 students (64 boys and 68 girls) aged between 10 and 13 years in public Elementary and Secondary Education schools of Seville towns, Arahal and Paradas (Spain). To determine the reliability, internal consistency was studied through Cronbach's alpha. The intraclass correlation coefficient (ICC) was also analyzed to calculate the optimal number of repetitions for future research. The validity was tested based on the assessment of a group of 5 experts. The results indicated that this new evaluation software reaches high levels of reliability and validit

    Introduction: Examined Live – An Epistemological Exchange Between Philosophy and Cultural Psychology on Reflection

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    Besides the general agreement about the human capability of reflection, there is a large area of disagreement and debate about the nature and value of “reflective scrutiny” and the role of “second-order states” in everyday life. This problem has been discussed in a vast and heterogeneous literature about topics such as epistemic injustice, epistemic norms, agency, understanding, meta-cognition etc. However, there is not yet any extensive and interdisciplinary work, specifically focused on the topic of the epistemic value of reflection. This volume is one of the first attempts aimed at providing an innovative contribution, an exchange between philosophy, epistemology and psychology about the place and value of reflection in everyday life. Our goal in the next sections is not to offer an exhaustive overview of recent work on epistemic reflection, nor to mimic all of the contributions made by the chapters in this volume. We will try to highlight some topics that have motivated a new resumption of this field and, with that, drawing on chapters from this volume where relevant. Two elements defined the scope and content of this volume, on the one hand, the crucial contribution of Ernest Sosa, whose works provide original and thought-provoking contributions to contemporary epistemology in setting a new direction for old dilemmas about the nature and value of knowledge, giving a central place to reflection. On the other hand, the recent developments of cultural psychology, in the version of the “Aalborg approach”, reconsider the object and scope of psychological sciences, stressing that “[h]uman conduct is purposeful”
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