14,614 research outputs found

    Observation of Bell Inequality violation in B mesons

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    A pair of B0Bˉ0B^0\bar B^0 mesons from Υ(4S)\Upsilon(4S) decay exhibit EPR type non-local particle-antiparticle (flavor) correlation. It is possible to write down Bell Inequality (in the CHSH form: S2S\le2) to test the non-locality assumption of EPR. Using semileptonic B0B^0 decays of Υ(4S)\Upsilon(4S) at Belle experiment, a clear violation of Bell Inequality in particle-antiparticle correlation is observed: S=2.725+-0.167(stat)+-0.092(syst)Comment: Conference Proceeding for Garda Lake Workshop 2003 "Mysteries, Puzzles and Paradoxes in Quantum Mechanics

    Generation of bipartite spin entanglement via spin-independent scattering

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    We consider the bipartite spin entanglement between two identical fermions generated in spin-independent scattering. We show how the spatial degrees of freedom act as ancillas for the creation of entanglement to a degree that depends on the scattering angle, θ\theta. The number of Slater determinants generated in the process is greater than 1, corresponding to genuine quantum correlations between the identical fermions. The maximal entanglement attainable of 1 ebit is reached at θ=π/2\theta=\pi/2. We also analyze a simple θ\theta dependent Bell's inequality, which is violated for π/4<θπ/2\pi/4<\theta\leq\pi/2. This phenomenon is unrelated to the symmetrization postulate but does not appear for unequal particles.Comment: 5 pages and 3 figures. Accepted in PR

    New selection rules for resonant Raman scattering on quantum wires

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    The bosonisation technique is used to calculate the resonant Raman spectrum of a quantum wire with two electronic sub-bands occupied. Close to resonance, the cross section at frequencies in the region of the inter sub-band transitions shows distinct peaks in parallel polarisation of the incident and scattered light that are signature of collective higher order spin density excitations. This is in striking contrast to the conventional selection rule for non-resonant Raman scattering according to which spin modes can appear only in perpendicular polarisation. We predict a new selection rule for the excitations observed near resonance, namely that, apart from charge density excitations, only spin modes with positive group velocities can appear as peaks in the spectra in parallel configuration close to resonance. The results are consistent with all of the presently available experimental data.Comment: 7 pages, 2 figure

    Quantum energy teleportation in a quantum Hall system

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    We propose an experimental method for a quantum protocol termed quantum energy teleportation (QET), which allows energy transportation to a remote location without physical carriers. Using a quantum Hall system as a realistic model, we discuss the physical significance of QET and estimate the order of energy gain using reasonable experimental parameters

    Peripheral arterial disease in rheumatoid arthritis patients at the Kenyatta National Hospital, Kenya

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    Objective: To determine the magnitude of the rosclerotic arterial disease in Rheumatoid Arthritis(RA) patients at Kenyatta National Hospital.Design: hospital based cross-sectional study.Setting: Kenyatta National Hospital Rheumatology outpatient clinic.Subjects: Rheumatoid Arthritis patients.Results: We obtained ABI measurements in 90 RA patients, among them 23(25.5% 95% CI 17.2-36.1) had obstructed lower limb arteries. Among the 23, 21(91.3%) had mild PAD, two (8.7%) had moderate PAD; none had severe PAD nor incompressible vessels. The obstruction of vessels was independent of diabetes, hypertension, dyslipidemia and cigarette smoking though these factors increased the likelihood of having PAD. Risk age( ≥45 males, ≥55 females), Established RA(&gt; 5 year duration) and severe RA were found to be significantly associated with the likelihood of having PAD. These trends remained significant after multivariable adjustment for potential confounders. twenty five (27.7%) of the study subjects exhibited symptoms of intermittent claudication, 13(52%) of them had PAD on ABI measurements, The Edinburgh claudication questionnaire was found to have 56.5% sensitivity and 82% specificity in detectionof PAD in RA patients. Conclusion: There seems to be an association between PAD in RA with chronicity and severity of the RA. This association may support the pathogenic role of accumulated systemic inflammation in atherosclerosis. Clinicians should be alert to the possibility of impared arterial function and thus subsequent cardiovascular morbidity and mortality in this group of patients

    Concentration dependence of the exchange interaction in Pb1-xEuxTe

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    [[abstract]]From low-field measurements of the susceptibility at temperatures up to 385 K, fitted to the Curie-Weiss expression, the exchange constant J/kB of Pb1-xEuxTe has been obtained for different values of x. It has been observed that J/kB decreases with increasing x. Reasons for this decrease are proposed. Measurements of the low-temperature magnetization at fields up to 23 T yield a value of the pair exchange constant Jp/kB, which is somewhat larger than the values from the susceptibility measurements and is nearly independent of x. This result seems to be due to the clustering of Eu atoms.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙本[[booktype]]電子

    Noisy Monte Carlo: Convergence of Markov chains with approximate transition kernels

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    Monte Carlo algorithms often aim to draw from a distribution π\pi by simulating a Markov chain with transition kernel PP such that π\pi is invariant under PP. However, there are many situations for which it is impractical or impossible to draw from the transition kernel PP. For instance, this is the case with massive datasets, where is it prohibitively expensive to calculate the likelihood and is also the case for intractable likelihood models arising from, for example, Gibbs random fields, such as those found in spatial statistics and network analysis. A natural approach in these cases is to replace PP by an approximation P^\hat{P}. Using theory from the stability of Markov chains we explore a variety of situations where it is possible to quantify how 'close' the chain given by the transition kernel P^\hat{P} is to the chain given by PP. We apply these results to several examples from spatial statistics and network analysis.Comment: This version: results extended to non-uniformly ergodic Markov chain

    Citra Perusahaan dan Kualitas Pelayanan Pengaruhnya terhadap Keputusan Menggunakan Jasa pada Sekolah Mengemudi Melati di Manado

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    Peningkatan kebutuhan akan ilmu pengetahuan mengakibatkan banyaknya persaingan dalam bisnis. Keberhasilan pengusaha untuk menarik dan mempertahankan pelanggan membutuhkan usaha, kerja keras dan inovasi dari pihak Perusahaan. Jika suatu Perusahaan memiliki kualitas pelayanan yang baik maka Perusahaan akan semakin memiliki banyak pelanggan dan citra dari Perusahaan itu sendiri juga akan baik sehingga menarik minat konsumen untuk memutuskan menggunakan suatu jasa. Penelitian ini bertujuan untuk mengetahui pengaruh Citra Perusahaan dan Kualitas Pelayanan terhadap Keputusan Menggunakan Jasa pada Sekolah Mengemudi Melati secara parsial dan simultan. Populasi dalam penelitian ini yaitu 43 pengguna jasa Sekolah Mengemudi Melati di Manado pada bulan Januari dan Februari dan sampel yang digunakan sebanyak 30 responden. Teknik analisis data menggunakan Analisis Korelasi dan Regresi Linear Berganda.Hasil penelitian menunjukkan bahwa secara bersama-sama atau simultan Citra Perusahaan dan Kualitas Pelayanan sebagai variabel bebas memiliki pengaruh terhadap Keputusan Konsumen untuk Menggunakan Jasa Perusahaan.Secara parsial Citra Perusahaan tidak memiliki pengaruh terhadap Keputusan Menggunakan Jasa sedangkan Kualitas Pelayanan secara parsial memiliki pengaruh terhadap Keputusan Menggunakan Jasa.Pihak Perusahaan perlu senantiasa meningkatkan Kualitas Pelayanan terhadap para konsumen sebab dengan meningkatnya Kualitas Pelayanan maka Keputusan Konsumen untuk Menggunakan Jasa juga akan semakin meningkat. Kata kunci: citra, kualitas pelayanan, keputusan pembelia

    Magnetic Fourier Integral Operators

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    In some previous papers we have defined and studied a 'magnetic' pseudodifferential calculus as a gauge covariant generalization of the Weyl calculus when a magnetic field is present. In this paper we extend the standard Fourier Integral Operators Theory to the case with a magnetic field, proving composition theorems, continuity theorems in 'magnetic' Sobolev spaces and Egorov type theorems. The main application is the representation of the evolution group generated by a 1-st order 'magnetic' pseudodifferential operator (in particular the relativistic Schr\"{o}dinger operator with magnetic field) as such a 'magnetic' Fourier Integral Operator. As a consequence of this representation we obtain some estimations for the distribution kernel of this evolution group and a result on the propagation of singularities
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