735 research outputs found

    Dimensional reduction and the phase diagram of 5d Yang-Mills theory

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    We present a non-perturbative study of the phase diagram of 5d SU(2) Yang-Mills theory with one compact extra dimension on the lattice. Assuming at least a modest scale separation between the cutoff and the compactification scales leads to an exponential separation between the compactification scale and the four-dimensional correlation length. While we demonstrate that it is not possible to take a full five-dimensional continuum limit, this dynamical generation of scale hierarchy opens up the possibility for us to make limited, but non-perturbative, predictions about continuum theories whose low-energy sector is described by an effective 5d Yang-Mills theory.Comment: 7 pages. Presented at the XXVII International Symposium on Lattice Field Theory, July 26-31, 2009, Peking University, Beijing, Chin

    The lowest modes around Gaussian solutions of tensor models and the general relativity

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    In the previous paper, the number distribution of the low-lying spectra around Gaussian solutions representing various dimensional fuzzy tori of a tensor model was numerically shown to be in accordance with the general relativity on tori. In this paper, I perform more detailed numerical analysis of the properties of the modes for two-dimensional fuzzy tori, and obtain conclusive evidences for the agreement. Under a proposed correspondence between the rank-three tensor in tensor models and the metric tensor in the general relativity, conclusive agreement is obtained between the profiles of the low-lying modes in a tensor model and the metric modes transverse to the general coordinate transformation. Moreover, the low-lying modes are shown to be well on a massless trajectory with quartic momentum dependence in the tensor model. This is in agreement with that the lowest momentum dependence of metric fluctuations in the general relativity will come from the R^2-term, since the R-term is topological in two dimensions. These evidences support the idea that the low-lying low-momentum dynamics around the Gaussian solutions of tensor models is described by the general relativity. I also propose a renormalization procedure for tensor models. A classical application of the procedure makes the patterns of the low-lying spectra drastically clearer, and suggests also the existence of massive trajectories.Comment: 31 pages, 8 figures, Added references, minor corrections, a misleading figure replace

    Separation of Cultivars of Soybeans by Chemometric Methods Using Near Infrared Spectroscopy.

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    Made available in DSpace on 2018-03-13T00:35:06Z (GMT). No. of bitstreams: 1 727942750021PB.pdf: 1034238 bytes, checksum: 5285573c242e3cac13b8cf10044c4eb3 (MD5) Previous issue date: 2018-03-12bitstream/item/173795/1/72794-275002-1-PB.pd

    Nonlocal regularisation of noncommutative field theories

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    We study noncommutative field theories, which are inherently nonlocal, using a Poincar\'e-invariant regularisation scheme which yields an effective, nonlocal theory for energies below a cut-off scale. After discussing the general features and the peculiar advantages of this regularisation scheme for theories defined in noncommutative spaces, we focus our attention onto the particular case when the noncommutativity parameter is inversely proportional to the square of the cut-off, via a dimensionless parameter η\eta. We work out the perturbative corrections at one-loop order for a scalar theory with quartic interactions, where the signature of noncommutativity appears in η\eta-dependent terms. The implications of this approach, which avoids the problems related to UV-IR mixing, are discussed from the perspective of the Wilson renormalisation program. Finally, we remark about the generality of the method, arguing that it may lead to phenomenologically relevant predictions, when applied to realistic field theories.Comment: 1+11 pages, 6 figures; v2: references added, typos corrected, conclusions unchange

    Shear and bulk viscosities for pure glue matter

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    Shear η\eta and bulk ζ\zeta viscosities are calculated in a quasiparticle model within a relaxation time approximation for pure gluon matter. Below TcT_c the confined sector is described within a quasiparticle glueball model. Particular attention is paid to behavior of the shear and bulk viscosities near TcT_c. The constructed equation of state reproduces the first-order phase transition for the glue matter. It is shown that with this equation of state it is possible to describe the temperature dependence of the shear viscosity to entropy ratio η/s\eta/s and the bulk viscosity to entropy ratio ζ/s\zeta/s in reasonable agreement with available lattice data but absolute values of the ζ/s\zeta/s ratio underestimate the upper limits of this ratio in the lattice measurements typically by an order of magnitude.Comment: 8 pages, 4 figures; the published versio

    On the linear increase of the flux tube thickness near the deconfinement transition

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    We study the flux tube thickness of a generic Lattice Gauge Theory near the deconfining phase transition. It is well known that the effective string model predicts a logarithmic increase of the flux tube thickness as a function of the interquark distance for any confining LGT at zero temperature. It is perhaps less known that this same model predicts a linear increase in the vicinity of the deconfinement transition. We present a precise derivation of this result and compare it with a set of high precision simulations in the case of the 3d gauge Ising model.Comment: 20 pages, 4 figures, minor changes. Accepted for publication in JHE

    Lithium and proton conducting gel-type membranes

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    We review the characteristics and the properties of various types of gel-type, ionically conducting membranes. We have mainly investigated two classes of membranes, one characterized by lithium ion transport and the other characterized by proton conductivity. We show that the former membranes are suitable to be used as separators in advanced lithium ion plastic batteries and that the latter show good promises to be considered as alternative, new separators in polymer electrolyte fuel cells. © 2003 Elsevier B.V. All rights reserved
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