278 research outputs found

    High-Probability Quantum State Transfer in the Alternating Open Chains of 1/2 Spins with XY Hamiltonian

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    This paper concerns the problem of non-ideal state transfer along the alternating open chain of spins s=1/2s=1/2 with XY Hamiltonian. It is found that the state transfer along the chain with even number of spins NN (N=4,6,8N=4,6,8) may be realized with high probability. Privilege of even NN in comparison with odd NN is demonstrated.Comment: 14 pages, 6 figure

    Дидактические возможности информационных и коммуникационных технологий в обучении математике в вузе

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    Now active information of mathematical education in technical colleges is observed. In the course of application of mathematical methods at the solution of practical tasks it is expedient to apply applied packages of the type MathCAD, MathLAB, Mathematica, Statistica, etc. Application of applied packages will allow to increase level of competences of students when using the received knowledge, skills and abilities in studying of mathematical disciplines.В настоящее время наблюдается активная информатизация математического образования в технических вузах. В процессе применения математических методов при решении практических задач целесообразно применять прикладные пакеты типа MathCAD, MathLAB, Mathematica, Statistica и др. Применение прикладных пакетов позволит повысить уровень компетенций студентов при использовании полученных знаний, навыков и умений в изучении математических дисциплин

    Különböző adalékok hatása az ellentétes töltésű polielektrolitok és tenzidek asszociációjára

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    Munkánk elsődleges célja az elektrolit ellentmondásos hatásának vizsgálata, értelmezése volt. Kutatásaink során polikation/anionos tenzid (PEI-NaDS) és polianion/kationos tenzid (PSS-DTAB, PSS-CTAB) elegyekkel foglalkoztunk. Az elektrolit egyik hatása akkor észlelhető, ha a polielektrolit-tenzid asszociátumok elkészítése során elektrosztatikusan stabilizált kolloid diszperzió képződik. Kis elektrolit koncentráció értékek esetén az elektrolit a diszperzió kinetikai stabilitását csökkenti. PEINaDS és PSS-CTAB elegyei esetén polielektrolit feleslegben egy szűk, és tenzidfeleslegben széles koncentráció tartományban keletkezik kinetikailag stabil kolloid diszperzió. Ugyanakkor PSS és DTAB elegyeinél nem sikerült tenzidfeleslegben kolloid diszperziót létrehozni. Az elektrolit másik hatása akkor figyelhető meg, ha a P/T elegyhez hozzáadott elektrolit jelentősen csökkenti a kötött tenzid mennyiségét, ugyanakkor a tenzid oldhatósága elegendően nagy marad az elektrolitoldatban. Nagy NaCl koncentráció esetén az elektrolit az egyensúlyi fázistulajdonságokra hat: nem történik asszociatív fázisszeparáció. Ezt a hatást észleltük PSS és alkil-trimetilammónium bromidok (DTAB, CTAB) elegyeiben – bizonyos sókoncentráció felett a teljes tenzidkoncentráció tartományban transzparens oldatokat kaptunk. Megállapítható, hogy az elektrolit kettős hatással bír az ellentétes töltésű polielektrolit-tenzid rendszerekre, annak minőségétől függ, hogy az elektrolit egyik, másik, vagy akár mindkét hatását látjuk. Ezek az eredmények érdekes felhasználást nyerhetnek a jövőben. Például polielektrolittenzid aggregátumok elektrosztatikusan stabilizált kolloid diszperziója lehetőséget teremt arra, hogy a részecskék hidrofób belsejükben apoláris anyagot raktározzanak, ami az elektrolit koncentráció hirtelen megemelésével felszabadítható. Más lehetőség lehet, hogy P/T nanorészecskékből álló felületi réteg létrehozásával a felület hidrofóbicitása hangolható a közeg ionerősségének változtatásával. A PEI-NaDS-PEO rendszerrel ellentétben a PSS-CTAB-Pluronic rendszerekben nem tapasztalható a semleges polimer oly mértékű adszorpciója a P/T nanorészecskék felszínére, ami sztérikus stabilizálást biztosítana a PSS-CTAB nanorészecskék kolloid diszperziójának. Az eddigi eredmények azonban nem nyújtanak elegendő információt a polimeradalék hatásáról a polielektrolit-tenzid asszociációra, ezért további vizsgálatok szükségesek

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

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    A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review
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