30,129 research outputs found

    Eigenvalues of Ruijsenaars-Schneider models associated with An1A_{n-1} root system in Bethe ansatz formalism

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    Ruijsenaars-Schneider models associated with An1A_{n-1} root system with a discrete coupling constant are studied. The eigenvalues of the Hamiltonian are givein in terms of the Bethe ansatz formulas. Taking the "non-relativistic" limit, we obtain the spectrum of the corresponding Calogero-Moser systems in the third formulas of Felder et al [20].Comment: Latex file, 25 page

    Free boson representation of DY(sl^(M+1N+1))DY_{\hbar}(\hat{sl} (M+1|N+1)) at level one

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    We construct a realization of the central extension of super-Yangian double DY(sl^(M+1N+1))DY_{\hbar}(\hat{sl}(M+1|N+1)) at level-one in terms of free boson fields with a continuous parameter.Comment: 9 pages, latex, reference revise

    q-deformed Supersymmetric t-J Model with a Boundary

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    The q-deformed supersymmetric t-J model on a semi-infinite lattice is diagonalized by using the level-one vertex operators of the quantum affine superalgebra Uq[sl(21)^]U_q[\hat{sl(2|1)}]. We give the bosonization of the boundary states. We give an integral expression of the correlation functions of the boundary model, and derive the difference equations which they satisfy.Comment: LaTex file 18 page

    Necessary and sufficient conditions for local creation of quantum discord

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    We show that a local channel cannot create quantum discord (QD) for zero QD states of size d3d\geq3 if and only if either it is a completely decohering channel or it is a nontrivial isotropic channel. For the qubit case this propertiy is additionally characteristic to the completely decohering channel or the commutativity-preserving unital channel. In particular, the exact forms of the completely decohering channel and the commutativity-preserving unital qubit channel are proposed. Consequently, our results confirm and improve the conjecture proposed by X. Hu et al. for the case of d3d\geq3 and improve the result proposed by A. Streltsov et al. for the qubit case. Furthermore, it is shown that a local channel nullifies QD in any state if and only if it is a completely decohering channel. Based on our results, some protocols of quantum information processing issues associated with QD, especially for the qubit case, would be experimentally accessible.Comment: 8 page

    A Sino-German 6cm polarisation survey of the Galactic plane IX. HII regions

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    Large-scale radio continuum surveys provide data to get insights into the physical properties of radio sources. HII regions are prominent radio sources produced by thermal emission of ionised gas around young massive stars. We identify and analyse HII regions in the Sino-German 6cm polarisation survey of the Galactic plane. Objects with flat radio continuum spectra together with infrared and/or Halpha emission were identified as HII regions. For HII regions with small apparent sizes, we cross-matched the 6cm small-diameter source catalogue with the radio HII region catalogue compiled by Paladini and the infrared HII region catalogue based on the WISE data. Extended HII regions were identified by eye by overlaying the Paladini and the WISE HII regions onto the 6cm survey images for coincidences. The TT-plot method was employed for spectral index verification. A total of 401 HII regions were identified and their flux densities were determined with the Sino-German 6cm survey data. In the surveyed area, 76 pairs of sources are found to be duplicated in the Paladini HII region catalogue, mainly due to the non-distinction of previous observations with different angular resolutions, and 78 objects in their catalogue are misclassified as HII regions, being actually planetary nebulae, supernova remnants or extragalactic sources that have steep spectra. More than 30 HII regions and HII region candidates from our 6cm survey data, especially extended ones, do not have counterparts in the WISE HII region catalogue, of which 9 are identified for the first time. Based on the newly derived radio continuum spectra and the evidence of infrared emission, the previously identified SNRs G11.1-1.0, G20.4+0.1 and G16.4-0.5 are believed to be HII regions.Comment: version after some minor corrections and language editing, full Table 2 - 5 will appear in CDS, accepted for publication in A&
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