927 research outputs found

    Graph states in phase space

    Full text link
    The phase space for a system of nn qubits is a discrete grid of 2n×2n2^{n} \times 2^{n} points, whose axes are labeled in terms of the elements of the finite field \Gal{2^n} to endow it with proper geometrical properties. We analyze the representation of graph states in that phase space, showing that these states can be identified with a class of non-singular curves. We provide an algebraic representation of the most relevant quantum operations acting on these states and discuss the advantages of this approach.Comment: 14 pages. 2 figures. Published in Journal of Physics

    Optimality of broken extremals

    Full text link
    In this paper we analyse the optimality of broken Pontryagin extremal for an n-dimensional affine control system with a control parameter, taking values in a k- dimensional closed ball. We prove the optimality of broken normal extremals when n = 3 and the controllable vector fields form a contact distribution, and when the Lie algebra of the controllable fields is locally orthogonal to the singular locus and the drift does not belong to it. Moreover, if k = 2, we show the optimality of any broken extremal even abnormal when the controllable fields do not form a contact distribution in the point of singularity.Comment: arXiv admin note: text overlap with arXiv:1610.0675

    Prenatal Exposure to Perfluorooctanoate and Risk of Overweight at 20 Years of Age: A Prospective Cohort Study

    Get PDF
    Background: Perfluoroalkyl acids are persistent compounds used in various industrial -applications. Of these compounds, perfluorooctanoate (PFOA) is currently detected in humans worldwide. A recent study on low-dose developmental exposure to PFOA in mice reported increased weight and elevated biomarkers of adiposity in postpubertal female offspring

    A Quantum Mechanical Model of the Reissner-Nordstrom Black Hole

    Get PDF
    We consider a Hamiltonian quantum theory of spherically symmetric, asymptotically flat electrovacuum spacetimes. The physical phase space of such spacetimes is spanned by the mass and the charge parameters MM and QQ of the Reissner-Nordstr\"{o}m black hole, together with the corresponding canonical momenta. In this four-dimensional phase space, we perform a canonical transformation such that the resulting configuration variables describe the dynamical properties of Reissner-Nordstr\"{o}m black holes in a natural manner. The classical Hamiltonian written in terms of these variables and their conjugate momenta is replaced by the corresponding self-adjoint Hamiltonian operator, and an eigenvalue equation for the ADM mass of the hole, from the point of view of a distant observer at rest, is obtained. Our eigenvalue equation implies that the ADM mass and the electric charge spectra of the hole are discrete, and the mass spectrum is bounded below. Moreover, the spectrum of the quantity M2Q2M^2-Q^2 is strictly positive when an appropriate self-adjoint extension is chosen. The WKB analysis yields the result that the large eigenvalues of the quantity M2Q2\sqrt{M^2-Q^2} are of the form 2n\sqrt{2n}, where nn is an integer. It turns out that this result is closely related to Bekenstein's proposal on the discrete horizon area spectrum of black holes.Comment: 37 pages, Plain TeX, no figure

    A study of the etapipi channel produced in central pp interactions at 450 GeV/c

    Get PDF
    The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870). In addition, there is evidence for an a0(980)pi$ decay mode of both resonances and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC = 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte

    A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states

    Get PDF
    The production and decay properties of the f0(1370), f0(1500), f0(2000) and f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT, phi and |t| distributions of these resonances are presented. For the J = 0 states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These are different to the dPT and phi dependences of the f0(980), f0(1500) and f0(1710). For the J = 2 states the f2(1950) has different dependences to the f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not just J phenomena.Comment: 14 pages, Latex, 4 Figure

    Identification of an epigenetic biomarker panel with high sensitivity and specificity for colorectal cancer and adenomas

    Get PDF
    Background The presence of cancer-specific DNA methylation patterns in epithelial colorectal cells in human feces provides the prospect of a simple, non-invasive screening test for colorectal cancer and its precursor, the adenoma. This study investigates a panel of epigenetic markers for the detection of colorectal cancer and adenomas. Methods Candidate biomarkers were subjected to quantitative methylation analysis in test sets of tissue samples from colorectal cancers, adenomas, and normal colonic mucosa. All findings were verified in independent clinical validation series. A total of 523 human samples were included in the study. Receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of the biomarker panel. Results Promoter hypermethylation of the genes CNRIP1, FBN1, INA, MAL, SNCA, and SPG20 was frequent in both colorectal cancers (65-94%) and adenomas (35-91%), whereas normal mucosa samples were rarely (0-5%) methylated. The combined sensitivity of at least two positives among the six markers was 94% for colorectal cancers and 93% for adenoma samples, with a specificity of 98%. The resulting areas under the ROC curve were 0.984 for cancers and 0.968 for adenomas versus normal mucosa. Conclusions The novel epigenetic marker panel shows very high sensitivity and specificity for both colorectal cancers and adenomas. Our findings suggest this biomarker panel to be highly suitable for early tumor detection
    corecore