6,259 research outputs found

    Searching for Effects of Spatial Noncommutativity via Chern-Simons' Processes

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    The possibility of testing spatial noncommutativity in the case of both position-position and momentum-momentum noncommuting via a Chern-Simons' process is explored. A Chern-Simons process can be realized by an interaction of a charged particle in special crossed electric and magnetic fields, in which the Chern-Simons term leads to non-trivial dynamics in the limit of vanishing kinetic energy. Spatial noncommutativity leads to the spectrum of the orbital angular momentum possessing fractional values. Furthermore, in both limits of vanishing kinetic energy and subsequent vanishing magnetic field, the Chern-Simons term leads to this system having non-trivial dynamics again, and the dominant value of the lowest orbital angular momentum being â„Ź/4\hbar/4, which is a clear signal of spatial noncommutativity. An experimental verification of this prediction by a Stern-Gerlach-type experiment is suggested.Comment: 18 page

    One way to Characterize the compact structures of lattice protein model

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    On the study of protein folding, our understanding about the protein structures is limited. In this paper we find one way to characterize the compact structures of lattice protein model. A quantity called Partnum is given to each compact structure. The Partnum is compared with the concept Designability of protein structures emerged recently. It is shown that the highly designable structures have, on average, an atypical number of local degree of freedom. The statistical property of Partnum and its dependence on sequence length is also studied.Comment: 10 pages, 5 figure

    Distinguishing a set of full product bases needs only projective measurements and classical communication

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    Nonlocality without entanglement is an interesting field. A manifestation of quantum nonlocality without entanglement is the local indistinguishability of a set of orthogonal product states. In this paper we analyze the character of operators to distinguish a set of full product bases in a multi-partite system, and show that distinguishing perfectly a set of full product bases needs only local projective measurements and classical communication, and these measurements cannot damage each product basis. Employing these conclusions one can discuss local distinguishability of full product bases easily. Finally we discuss the generalization of these results to the locally distinguishability of a set of incomplete product bases

    Primeiros resultados de milho e caupi cultivados em uma área de mata secundária com e sem emprego de fogo.

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    Enhanced flux pinning in YBa2Cu3O7-d films by nano-scaled substrate surface roughness

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    Nano-scaled substrate surface roughness is shown to strongly influence the critical current density Jc in YBCO films made by pulse-laser-deposition on the crystalline LaAlO3 substrates consisting of two separate twin-free and twin-rich regions. The nano-scaled corrugated surface was created in the twin-rich region during the deposition process. Using magneto-optical imaging techniques coupled with optical and atomic force microscopy, we observed an enhanced flux pinning in the YBCO films in the twin-rich region, resulted in \~30% increase in Jc, which was unambiguously confirmed by the direct transport measurement.Comment: 16 pages, 3 figures, accepted by Applied Physics Letter

    Stillbirth should be given greater priority on the global health agenda

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    Stillbirths are largely excluded from international measures of mortality and morbidity. Zeshan Qureshi and colleagues argue that stillbirth should be higher on the global health agenda

    Measure representation and multifractal analysis of complete genomes

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    This paper introduces the notion of measure representation of DNA sequences. Spectral analysis and multifractal analysis are then performed on the measure representations of a large number of complete genomes. The main aim of this paper is to discuss the multifractal property of the measure representation and the classification of bacteria. From the measure representations and the values of the DqD_{q} spectra and related CqC_{q} curves, it is concluded that these complete genomes are not random sequences. In fact, spectral analyses performed indicate that these measure representations considered as time series, exhibit strong long-range correlation. For substrings with length K=8, the DqD_{q} spectra of all organisms studied are multifractal-like and sufficiently smooth for the CqC_{q} curves to be meaningful. The CqC_{q} curves of all bacteria resemble a classical phase transition at a critical point. But the 'analogous' phase transitions of chromosomes of non-bacteria organisms are different. Apart from Chromosome 1 of {\it C. elegans}, they exhibit the shape of double-peaked specific heat function.Comment: 12 pages with 9 figures and 1 tabl

    Representation Class and Geometrical Invariants of Quantum States under Local Unitary Transformations

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    We investigate the equivalence of bipartite quantum mixed states under local unitary transformations by introducing representation classes from a geometrical approach. It is shown that two bipartite mixed states are equivalent under local unitary transformations if and only if they have the same representation class. Detailed examples are given on calculating representation classes.Comment: 11 page
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