4,158,440 research outputs found

    Sliding elastic lattice: an explanation of the motion of superconducting vortices

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    We introduce a system where an elastic lattice of particles is moved slowly at a constant velocity under the influence of a local external potential, construct a rigid-body model through simplification processes, and show that the two systems produce similar results. Then, we apply our model to a superconducting vortex system and produce path patterns similar to the ones reported in [Lee et al., Phys. Rev. B 84, 060515 (2011)] suggesting that the reasoning of the simplification processes in this paper can be a possible explanation of the experimentally observed phenomenon.Comment: 5 pages, 3 figures, Submitted to Physical Review Letters; Reference [17] Lee et al., Phys. Rev. B Accepted changed to Lee et al., Phys. Rev. B 84, 060515 (2011

    The Friedberg-Lee model at finite temperature and density

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    The Friedberg-Lee model is studied at finite temperature and density. By using the finite temperature field theory, the effective potential of the Friedberg-Lee model and the bag constant B(T)B(T) and B(T,μ)B(T,\mu) have been calculated at different temperatures and densities. It is shown that there is a critical temperature TC≃106.6MeVT_{C}\simeq 106.6 \mathrm{MeV} when μ=0MeV\mu=0 \mathrm{MeV} and a critical chemical potential μ≃223.1MeV\mu \simeq 223.1 \mathrm{MeV} for fixing the temperature at T=50MeVT=50 \mathrm{MeV}. We also calculate the soliton solutions of the Friedberg-Lee model at finite temperature and density. It turns out that when T≤TCT\leq T_{C} (or μ≤μC\mu \leq \mu_C), there is a bag constant B(T)B(T) (or B(T,μ)B(T,\mu)) and the soliton solutions are stable. However, when T>TCT>T_{C} (or μ>μC\mu>\mu_C) the bag constant B(T)=0MeVB(T)=0 \mathrm{MeV} (or B(T,μ)=0MeVB(T,\mu)=0 \mathrm{MeV}) and there is no soliton solution anymore, therefore, the confinement of quarks disappears quickly.Comment: 12 pages, 11 figures; version accepted for publication in Phys. Rev.

    Possible Triplet Electron Pairing and an Anisotropic Spin Susceptibility in Organic Superconductors (TMTSF)_2 X

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    We argue that (TMTSF)_2 PF_6 compound under pressure is likely a triplet superconductor with a vector order parameter d(k) \equiv (d_a(k) \neq 0, d_c(k) = ?, d_{b'}(k) = 0); |d_a(k)| > |d_c(k)|. It corresponds to an anisotropic spin susceptibility at T=0: \chi_{b'} = \chi_0, \chi_a \ll \chi_0, where \chi_0 is its value in a metallic phase. [The spin quantization axis, z, is parallel to a so-called b'-axis]. We show that the suggested order parameter explains why the upper critical field along the b'-axis exceeds all paramagnetic limiting fields, including that for a nonuniform superconducting state, whereas the upper critical field along the a-axis (a \perp b') is limited by the Pauli paramagnetic effects [I. J. Lee, M. J. Naughton, G. M. Danner and P. M. Chaikin, Phys. Rev. Lett. 78, 3555 (1997)]. The triplet order parameter is in agreement with the recent Knight shift measurements by I. J. Lee et al. as well as with the early results on a destruction of superconductivity by nonmagnetic impurities and on the absence of the Hebel-Slichter peak in the NMR relaxation rate.Comment: 4 pages, 1 eps figur

    On the nonlinear statistics of range image patches

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    In [A. B. Lee, K. S. Pedersen, and D. Mumford, Int. J. Comput. Vis., 54 (2003), pp. 83–103], the authors study the distributions of 3 × 3 patches from optical images and from range images. In [G. Carlsson, T. Ishkanov, V. de Silva, and A. Zomorodian, Int. J. Comput. Vis., 76 (2008), pp. 1–12], the authors apply computational topological tools to the data set of optical patches studied by Lee, Pedersen, and Mumford and find geometric structures for high density subsets. One high density subset is called the primary circle and essentially consists of patches with a line separating a light and a dark region. In this paper, we apply the techniques of Carlsson et al. to range patches. By enlarging to 5×5 and 7×7 patches, we find core subsets that have the topology of the primary circle, suggesting a stronger connection between optical patches and range patches than was found by Lee, Pedersen, and Mumford

    Explicit Presentations for the Dual Braid Monoids

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    Birman, Ko and Lee have introduced a new monoid Bn∗{\cal B}^{*}_{n}--with an explicit presentation--whose group of fractions is the nn-strand braid group Bn{\cal B}_{n}. Building on a new approach by Digne, Michel and himself, Bessis has defined a {\it dual} braid monoid for every finite Coxeter type Artin-Tits group extending the type A case. Here, we give an explicit presentation for this dual braid monoid in the case of types B and D, and we study the combinatorics of the underlying Garside structures.Comment: 6 pages, 4 figure

    The Effect of Partial Information Sharing in a Two-Level Supply Chain

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    In many supply chains, the variance of orders may be considerably larger than that of sales, and this distortion tends to increase as one moves up a supply chain, this is known as "Bullwhip Effect". The Bullwhip phenomenon has recognized in many diverse markets. Procter & Gamble found that the diaper orders issued by the distributors have a degree of variability that cannot be explained by consumer demand fluctuations (Lee, Padamanabhan and Wang 1997a). Lee, Padamanabhan and Wang (1997a, b) developed a framework for explaining this phenomenon. Lee, So, and Tang (2000) showed that, within the context of a two-level supply chain consisting of single manufacturer and single retailer with AR(1) end demand, the manufacturer would benefit when the retailer shared its demand information. This paper considers the eRect of partial information sharing, within the framework of Lee, So and Tang, in one manufacturer and n retailers model, focusing on the variance of the manufacturer's "demand" (the retailers' order quantity).Supply Chain Management, Information Sharing, Inventory

    Green B. Lee.

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    Report : Petition of G. Lee. [2807] Florida Indian war; 1838
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