643 research outputs found

    Statistical quantum operation

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    A generic unital positive operator-valued measure (POVM), which transforms a given stationary pure state to an arbitrary statistical state with perfect decoherence, is presented. This allows one to operationally realize thermalization as a special case. The loss of information due to randomness generated by the operation is discussed by evaluating the entropy. Thermalization of the bipartite spin-1/2 system is discussed as an illustrative example.Comment: 10 pages, no figure

    Stationary photon-atom entanglement and flow equation

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    Stationary photon-atom entanglement is discussed by applying the method of flow equation to the Jaynes-Cummings model. A nonlocal continuous unitary transformation is explicitly constructed and the associated positive operator-valued measures for the photons and atom are obtained. Then, flow of the entanglement entropy is analyzed. A comment is also made on implementing the unitary operation in the method of flow equation. This method may offer a new strategy for quantum-state engineering.Comment: 21 pages, no figure

    Performance of segment type switched reluctance motor using grain-oriented

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    Authors developed a segment type switched reluctance motor (SRM) as a rare earth less motor. The object is to reduce the acoustic noise and vibration as well as improve the torque characteristics. In this paper, we propose the performance improve method using grain-oriented electric steel as the segment core. The validity is confirmed experimentally.15th International Conference on Electrical Machines and Systems, ICEMS 2012; Sapporo; Japan; 21 October 2012 ~ 24 October 201

    Plasma calcium and calcitonin levels at food intake in eels and goldfish

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    金沢大学環日本海域環境研究センター生物多様性研究部門In order to examine whether calcitonin plays an important role in Ca homeostasis of teleosts, such as suppressing hypercalcemia at food intake, we compared the plasma Ca levels and calcitonin levels in eels fed normally with eels starved for one week (Experiment I), and in goldfish administered with a high Ca-consomme solution into the digestive tract with goldfish given physiological saline solution (Experiment II). In Experiment I, the plasma Ca levels and calcitonin levels in the fed eels were significantly higher than those in the starved eels after one week. In Experiment II, the plasma Ca levels in the high Ca-treated goldfish were significantly higher than those in the saline-treated goldfish after 1 hr and 3 hr. The number of goldfish showing over 500 pg/ml of plasma calcitonin was significantly higher in the high Ca-treated group than in the saline-treated group. From the results of both experiments, we conclude that in these two species, Ca and/or nutriment absorbed via the digestive tract may affect plasma calcitonin levels. However, more experiments are needed to directly demonstrate that calcitonin suppresses hypercalcemia at food intake

    Characteristics of a half-wave rectified brushless synchronous generator

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    The paper proposes the half-wave rectified brushless synchronous generator and analyzes the basic characteristics using the finite element method. It is based on the half-wave rectified excitation theory and doesn\u27t need brush and slip ring system or permanent magnets for field excitation.7th International Power Electronics Conference, IPEC-Hiroshima - ECCE Asia 2014; Hiroshima; Japan; 18 May 2014 through 21 May 201

    A characteristic experiment of 4-phase segment type switched reluctance motor

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    Authors developed a novel segment type switched reluctance motor (SRM) as a rare earth less motor. The torque was increased by 40% and the radial force was decreased by 76% compared with the same size VR type SRM. Increasing the average torque, however, caused increasing torque ripple. In this paper we propose a 4-phase segment type switched reluctance motor and show that the torque ripple can be decreased by controlling the excitation current.15th International Conference on Electrical Machines and Systems, ICEMS 2012; Sapporo; Japan; 21 October 2012 ~ 24 October 201

    On the improvement performance of a dual rotor segment type SRM

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    A dual rotor segment type switched reluctance motor (SRM) is proposed for flat configuration. It has toroidal stator coil and has inner rotor as well as outer rotor. The performance characteristics are calculated using finite element method. On a flat type SRM, leakage flux is greatly generated at both side coil. To reduce the leakage flux we propose shield structure. Effectiveness of the shield structure is verified analytically.2013 IEEE 10th International Conference on Power Electronics and Drive Systems, PEDS 2013; Kitakyushu; Japan; 22 April 2013 through 25 April 201

    FOREVER22: the first bright galaxies with population III stars at redshifts z1020z \simeq 10-20 and comparisons with JWST data

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    We study the formation of the first galaxies in overdense regions modelled by the FORmation and EVolution of galaxies in Extremely overdense Regions motivated by SSA22 (FOREVER22) simulation project. Our simulations successfully reproduce the star formation rates and the MUVMstarM_{\rm UV}-M_{\rm star} relations of candidate galaxies at z1014z \sim 10-14 observed by the James Webb Space Telescope (JWST). We suggest that the observed galaxies are hosted by dark-matter haloes with Mh1010 MM_{\rm h} \gtrsim 10^{10}~{\rm M_{\odot}} and are in short-period starburst phases. On the other hand, even simulated massive galaxies in overdense regions cannot reproduce the intense star formation rates and the large stellar masses of observed candidates at z16z \sim 16. Also, we show that the contribution of population III stars to the UV flux decreases as the stellar mass increases and it is a few percent for galaxies with Mstar107 MM_{\rm star} \sim 10^{7}~{\rm M_{\odot}}. Therefore, a part of the observed flux by JWST could be the light from population III stars. Our simulations suggest that the UV flux can be dominated by population III stars and the UV-slope shows β3\beta \lesssim -3 if future observations would reach galaxies with Mstars105 MM_{\rm stars} \sim 10^{5}~{\rm M_{\odot}} at z20z \sim 20 of which the mass fraction of population III stars can be greater than 10 percent.Comment: 9 pages, 6 figures, accepted for publication in MNRA
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