2,878 research outputs found

    Semiquantum key distribution using entangled states

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    Recently, Boyer et al. presented a novel semiquantum key distribution protocol [M. Boyer, D. Kenigsberg, and T. Mor, Phys. Rev. Lett. 99, 140501 (2007)], by using four quantum states, each of which is randomly prepared by Z basis or X basis. Here we present a semiquantum key distribution protocol by using entangled states in which quantum Alice shares a secret key with classical Bob. We also show the protocol is secure against eavesdropping.Comment: 6 page

    Optical generation of hybrid entangled state via entangling single-photon-added coherent state

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    We propose a feasible scheme to realize the optical entanglement of single-photon-added coherent state (SPACS) and show that, besides the Sanders entangled coherent state, the entangled SPACS also leads to new forms of hybrid entanglement of quantum Fock state and classical coherent state. We probe the essential difference of two types of hybrid entangled state (HES). This HES provides a novel link between the discrete- and the continuous-variable entanglement in a natural way.Comment: 6 pages, 2 figure

    Inherent SM Voltage Balance for Multilevel Circulant Modulation in Modular Multilevel DC--DC Converters

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    The modularity of a modular multilevel dc converter (MMDC) makes it attractive for medium-voltage distribution systems. Inherent balance of submodule (SM) capacitor voltages is considered as an ideal property, which avoids a complex sorting process based on many measurements thereby reducing costs and enhancing reliability. This article extends the inherent balance concept previously shown for square-wave modulation to a multilevel version for MMDCs. A switching duty matrix dU is introduced: it is a circulant matrix of preset multilevel switching patterns with multiple stages and multiple durations. Inherent voltage balance is ensured with a full-rank dU . Circulant matrix theory shows that this is equivalent to a simplified common factor criterion. A nonfull rank dU causes clusters of SM voltage rather than a single common value, with the clusters indicated by the kernel of the matrix. A generalized coprime criterion is developed into several deductions that serve as practical guidance for design of multilevel circulant modulation. The theoretical development is verified through full-scale simulations and downscaled experiments. The effectiveness of the proposed circulant modulation in achieving SM voltage balance in an MMDC is demonstrated

    Merger time scale of galaxies

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    Abstract. In this talk, we present our recent study of galaxy mergers in a high-resolution cosmological hydro/N-body simulation with star formation, and compare the measured merger timescales with theoretical predictions based on the Chandrasekhar formula. In contrast to Navarro et al., our numerical results indicate, that the commonly used equation for the merger timescale given by Lacey and Cole, systematically underestimates the merger timescales for minor mergers and overestimates those for major mergers. This behavior is partly explained by the poor performance of their expression for the Coulomb logarithm, ln(/Wpri//Wsat). The two alternative forms ln(l +/Wpri//Wsat) and l/2In[l + [m^^/msnt) ] for the Coulomb logarithm can account for the mass dependence of merger timescale successfiilly, but both of them underestimate the merger time scale by a factor 2. Since ln(l + /Wpn/msat) represents the mass dependence slightly better we adopt this expression for the Coulomb logarithm. Furthermore, we find that the dependence of the merger timescale on the circularity parameter e is much weaker than the widely adopted power-law e, whereas 0.94 * e"" " + 0.60 provides a good match to the data. Based on these findings, we present an accurate and convenient fitting formula for the merger timescale of galaxies in cold dark matter models

    Eprosartan mesylate, an angiotensin II receptor antagonist

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    The title compound, eprosartan mesylate {systematic name: 2-butyl-1-(4-carb­oxy­benz­yl)-5-[(E)-2-carb­oxy-3-(thio­phen-2-yl)prop-1-en­yl]-1H-imidazol-3-ium methane­sulfonate}, C23H25N2O4S+·CH3O3S−, one of the angiotensin II-receptor antagonists, is effective in regulating hypertension, induced or exacerbated by angiotensin II, and in the treatment of congestive heart failure, renal failure and glaucoma. In the eprosartan residue, which appears in this crystal in the cationic imidazolium form, the benzene ring plane is almost orthogonal to that of the imidazole ring, making a dihedral angle of 87.89 (2)°. The thio­phene ring forms dihedral angles of 66.54 (2) and 67.12 (2)° with the benzene and imidazole rings, respectively. The imidazolium NH group and the H atom of the aromatic carboxyl group participate in hydrogen bonds with the the O atoms of the anion, thus forming centrosymmetric aggregates made up of two cations and two anions each. The second carboxyl group further links the above-mentioned aggregates through a conventional centrosymmetric hydrogen-bonding motif into infinite chains along [011]

    An interpretation for the entropy of a black hole

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    We investigate the meaning of the entropy carried away by Hawking radiations from a black hole. We propose that the entropy for a black hole measures the uncertainty of the information about the black hole forming matter's precollapsed configurations, self-collapsed configurations, and inter-collapsed configurations. We find that gravitational wave or gravitational radiation alone cannot carry all information about the processes of black hole coalescence and collapse, while the total information locked in the hole could be carried away completely by Hawking radiation as tunneling

    Health effects of high serum calcium levels:Updated phenome-wide Mendelian randomisation investigation and review of Mendelian randomisation studies

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    BACKGROUND: Calcium plays a role in a wide range of biological functions. Here we conducted a phenome-wide Mendelian randomisation (MR-PheWAS) analysis and a systematic review for MR studies to comprehensively investigate the health effects of serum calcium. METHODS: One-hundred and thirty genetic variants strongly associated with serum calcium levels were used as instrumental variables. A phenome-wide association analysis (PheWAS) was conducted to examine the associations of genetically predicted serum calcium with 1473 distinct phenotypes in the UK Biobank including 339,197 individuals. Observed associations in PheWAS were further tested for replication in two-sample MR replication analysis. A systematic review for MR studies on serum calcium was performed to synthesize the published evidence and compare with the current MR-PheWAS findings. FINDINGS: Higher genetically predicted calcium levels were associated with decreased risk of 5 diseases in dermatologic and musculoskeletal systems and increased risk of 17 diseases in circulatory, digestive, endocrine, genitourinary and immune systems. Eight associations were replicated in two-sample MR analysis. These included decreased risk of osteoarthritis and increased risk of coronary artery disease, myocardial infarction, coronary atherosclerosis, hyperparathyroidism, disorder of parathyroid gland, gout, and calculus of kidney and ureter with increased serum calcium. Systematic review of 25 MR studies provided supporting evidence on five out of the eight disease outcomes, while the increased risk of gout, hyperparathyroidism and disorder of parathyroid gland were novel findings. INTERPRETATION: This study found wide-ranged health effects of high serum calcium, which suggests that the benefits and adversities of strategies promoting calcium intake should be assessed. FUNDING: ET is supported by a CRUK Career Development Fellowship (C31250/A22804). XL is supported by the Natural Science Fund for Distinguished Young Scholars of Zhejiang Province. SCL acknowledges research funding from the Swedish Heart Lung Foundation (Hjärt-Lungfonden, 20210351), the Swedish Research Council (Vetenskapsrådet, 2019-00977), and the Swedish Cancer Society (Cancerfonden)

    Low-lying S-wave and P-wave Dibaryons in a Nodal Structure Analysis

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    The dibaryon states as six-quark clusters of exotic QCD states are investigated in this paper. With the inherent nodal surface structure analysis, the wave functions of the six-quark clusters (in another word, the dibaryons) are classified. The contribution of the hidden color channels are discussed. The quantum numbers of the low-lying dibaryon states are obtained. The States [ΩΩ](0,0+)[\Omega\Omega]_{(0,0^{+})}, [ΩΩ](0,2)[\Omega\Omega]_{(0,2^{-})}, [ΞΩ](1/2,0+)[\Xi^{*}\Omega]_{(1/2,0^{+})}, [ΣΣ](0,4)[\Sigma^{*}\Sigma^{*}]_{(0,4^{-})} and the hidden color channel states with the same quantum numbers are proposed to be the candidates of dibaryons, which may be observed in experiments.Comment: 29 pages, 2 figure
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