898 research outputs found

    Novel Constructions of Mutually Unbiased Tripartite Absolutely Maximally Entangled Bases

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    We develop a new technique to construct mutually unbiased tripartite absolutely maximally entangled bases. We first explore the tripartite absolutely maximally entangled bases and mutually unbiased bases in CdCdCd\mathbb{C}^{d} \otimes \mathbb{C}^{d} \otimes \mathbb{C}^{d} based on mutually orthogonal Latin squares. Then we generalize the approach to the case of Cd1Cd2Cd1d2\mathbb{C}^{d_{1}} \otimes \mathbb{C}^{d_{2}} \otimes \mathbb{C}^{d_{1}d_{2}} by mutually weak orthogonal Latin squares. The concise direct constructions of mutually unbiased tripartite absolutely maximally entangled bases are remarkably presented with generality. Detailed examples in C3C3C3,\mathbb{C}^{3} \otimes \mathbb{C}^{3} \otimes \mathbb{C}^{3}, C2C2C4\mathbb{C}^{2} \otimes \mathbb{C}^{2} \otimes \mathbb{C}^{4} and C2C5C10\mathbb{C}^{2} \otimes \mathbb{C}^{5} \otimes \mathbb{C}^{10} are provided to illustrate the advantages of our approach

    Mutually unbiased maximally entangled bases from difference matrices

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    Based on maximally entangled states, we explore the constructions of mutually unbiased bases in bipartite quantum systems. We present a new way to construct mutually unbiased bases by difference matrices in the theory of combinatorial designs. In particular, we establish qq mutually unbiased bases with q1q-1 maximally entangled bases and one product basis in CqCq\mathbb{C}^q\otimes \mathbb{C}^q for arbitrary prime power qq. In addition, we construct maximally entangled bases for dimension of composite numbers of non-prime power, such as five maximally entangled bases in C12C12\mathbb{C}^{12}\otimes \mathbb{C}^{12} and C21C21\mathbb{C}^{21}\otimes\mathbb{C}^{21}, which improve the known lower bounds for d=3md=3m, with (3,m)=1(3,m)=1 in CdCd\mathbb{C}^{d}\otimes \mathbb{C}^{d}. Furthermore, we construct p+1p+1 mutually unbiased bases with pp maximally entangled bases and one product basis in CpCp2\mathbb{C}^p\otimes \mathbb{C}^{p^2} for arbitrary prime number pp.Comment: 24 page

    Quantum kk-uniform states from quantum orthogonal arrays

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    The quantum orthogonal arrays define remarkable classes of multipartite entangled states called kk-uniform states whose every reductions to kk parties are maximally mixed. We present constructions of quantum orthogonal arrays of strength 2 with levels of prime power, as well as some constructions of strength 3. As a consequence, we give infinite classes of 2-uniform states of NN systems with dimension of prime power d2d\geq 2 for arbitrary N5N\geq 5; 3-uniform states of NN-qubit systems for arbitrary N6N\geq 6 and N7,8,9,11N\neq 7,8,9,11; 3-uniform states of NN systems with dimension of prime power d7d\geq 7 for arbitrary N7N\geq 7.Comment: 26 pages, 1 figure

    DTNBP1, a schizophrenia susceptibility gene, affects kinetics of transmitter release

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    Schizophrenia is one of the most debilitating neuropsychiatric disorders, affecting 0.5–1.0% of the population worldwide. Its pathology, attributed to defects in synaptic transmission, remains elusive. The dystrobrevin-binding protein 1 (DTNBP1) gene, which encodes a coiled-coil protein, dysbindin, is a major susceptibility gene for schizophrenia. Our previous results have demonstrated that the sandy (sdy) mouse harbors a spontaneously occurring deletion in the DTNBP1 gene and expresses no dysbindin protein (Li, W., Q. Zhang, N. Oiso, E.K. Novak, R. Gautam, E.P. O'Brien, C.L. Tinsley, D.J. Blake, R.A. Spritz, N.G. Copeland, et al. 2003. Nat. Genet. 35:84–89). Here, using amperometry, whole-cell patch clamping, and electron microscopy techniques, we discovered specific defects in neurosecretion and vesicular morphology in neuroendocrine cells and hippocampal synapses at the single vesicle level in sdy mice. These defects include larger vesicle size, slower quantal vesicle release, lower release probability, and smaller total population of the readily releasable vesicle pool. These findings suggest that dysbindin functions to regulate exocytosis and vesicle biogenesis in endocrine cells and neurons. Our work also suggests a possible mechanism in the pathogenesis of schizophrenia at the synaptic level

    Effects of two different anesthesia-analgesia methods on incidence of postoperative delirium in elderly patients undergoing major thoracic and abdominal surgery: study rationale and protocol for a multicenter randomized controlled trial

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    Background: Delirium is a common complication in elderly patients after surgery and associated with increased morbidity and mortality. Studies suggest that deep anesthesia and intense pain are important precipitating factors of postoperative delirium. Neuraxial block is frequently used in combination with general anesthesia for patients undergoing major thoracic and abdominal surgery. Compared with general anesthesia alone and postoperative intravenous analgesia, combined epidural-general anesthesia and postoperative epidural analgesia decreases the requirement of general anesthetics during surgery and provided better pain relief after surgery. However, whether combined epidural-general anesthesia plus epidural analgesia is superior to general anesthesia plus intravenous analgesia in decreasing the incidence of postoperative delirium remains unknown. Methods/design: This is a multicenter, open-label, randomized, parallel-controlled clinical trial. One thousand eight hundred elderly patients (age range 60-90 years) who are scheduled to undergo major thoracic or abdominal surgery are randomized to receive either general anesthesia plus postoperative intravenous analgesia or combined epidural-general anesthesia plus postoperative epidural analgesia. The primary outcome is the 7-day incidence of postoperative delirium. Secondary outcomes include the duration of postoperative delirium, the intensity of pain during the first three days after surgery, the 30-day incidences of postoperative non-delirium complications, the length of stay in hospital after surgery and 30-day all-cause mortality. Discussion: Results of the present study will provide information to guide clinical practice in choosing appropriate anesthesia-analgesia method for elderly patients undergoing major thoracic and abdominal surgery.Fundamental Research Funds for the Central Universities-Peking University Clinical Research Program in Peking University Health Science Center [PUCRP201101]; Peking University First HospitalSCI(E)[email protected]

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    Search for dark matter in events with a leptoquark and missing transverse momentum in proton-proton collisions at 13 TeV

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    A search is presented for dark matter in proton-proton collisions at a center-of-mass energy of root s= 13 TeV using events with at least one high transverse momentum (p(T)) muon, at least one high-p(T) jet, and large missing transverse momentum. The data were collected with the CMS detector at the CERN LHC in 2016 and 2017, and correspond to an integrated luminosity of 77.4 fb(-1). In the examined scenario, a pair of scalar leptoquarks is assumed to be produced. One leptoquark decays to a muon and a jet while the other decays to dark matter and low-p(T) standard model particles. The signature for signal events would be significant missing transverse momentum from the dark matter in conjunction with a peak at the leptoquark mass in the invariant mass distribution of the highest p(T) muon and jet. The data are observed to be consistent with the background predicted by the standard model. For the first benchmark scenario considered, dark matter masses up to 500 GeV are excluded for leptoquark masses m(LQ) approximate to 1400 GeV, and up to 300 GeV for m(LQ) approximate to 1500 GeV. For the second benchmark scenario, dark matter masses up to 600 GeV are excluded for m(LQ) approximate to 1400 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe

    Measurement of electroweak WZ boson production and search for new physics in WZ + two jets events in pp collisions at √s=13TeV

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    A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′, where ℓ,ℓ′=e,μ. The analysis is based on a data sample of proton-proton collisions at √s=13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb−1. The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented
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