21,651 research outputs found

    Bosonization and entanglement spectrum for one-dimensional polar bosons on disordered lattices

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    The extended Bose-Hubbard model subjected to a disordered potential is predicted to display a rich phase diagram. In the case of uniform random disorder one finds two insulating quantum phases -- the Mott-insulator and the Haldane insulator -- in addition to a superfluid and a Bose glass phase. In the case of a quasiperiodic potential further phases are found, eg the incommensurate density wave, adiabatically connected to the Haldane insulator. For the case of weak random disorder we determine the phase boundaries using a perturbative bosonization approach. We then calculate the entanglement spectrum for both types of disorder, showing that it provides a good indication of the various phases.Comment: Submitted to NJ

    Reduction of mm-Regular Noncrossing Partitions

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    In this paper, we present a reduction algorithm which transforms mm-regular partitions of [n]={1,2,...,n}[n]=\{1, 2, ..., n\} to (m−1)(m-1)-regular partitions of [n−1][n-1]. We show that this algorithm preserves the noncrossing property. This yields a simple explanation of an identity due to Simion-Ullman and Klazar in connection with enumeration problems on noncrossing partitions and RNA secondary structures. For ordinary noncrossing partitions, the reduction algorithm leads to a representation of noncrossing partitions in terms of independent arcs and loops, as well as an identity of Simion and Ullman which expresses the Narayana numbers in terms of the Catalan numbers

    Analyzing the Key Drivers of Contractors’ Temporary Competitive Advantage in the Competition of International High-speed Rail Projects

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    This is a pre-print of an article published in KSCE Journal of Civil Engineering. The final authenticated version is available online at: https://doi.org/10.1007/s12205-019-0602-4 After temporary competitive advantage (TCA) being proposed, this concept has received a lot of attention from academia and industry. For international HSR contractors, how to form their TCA and win out over the competition for new projects is crucial, while only a few studies focus on this issue. This research aims to develop a TCA system that reflects the characteristics of high-speed rail (HSR) contractors in the corporation and project levels. At first, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) was conducted to explore and examine the key drivers and their relationships with contractors’ TCA

    Nuclear Magnetic Resonance Implementation of a Quantum Clock Synchronization Algorithm

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    The quantum clock synchronization algorithm proposed by I. L. Chuang (Phys. Rev. Lett, 85, 2006(2000)) has been implemented in a three qubit nuclear magnetic resonance quantum system. The effective-pure state is prepared by the spatial averaging approach. The time difference between two separated clocks can be determined by reading out directly through the NMR spectra.Comment: 13 pages, 5 figure

    Heavy Pentaquarks

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    We construct the spin-flavor wave functions of the possible heavy pentaquarks containing an anti-charm or anti-bottom quark using various clustered quark models. Then we estimate the masses and magnetic moments of the JP=12+J^P={1\over 2}^+ or 32+{3\over 2}^+ heavy pentaquarks. We emphasize the difference in the predictions of these models. Future experimental searches at BESIII, CLEOc, BELLE, and LEP may find these interesting states
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