21,224 research outputs found

    4D Tropospheric Tomography using GPS Estimated Slant Delays

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    Tomographic techniques are successfully applied to obtain 4D images of the tropospheric refractivity in a local dense network. In the lower atmosphere both the small height and time scales and the non-dispersive nature of tropospheric delays require a more careful analysis of the data. We show how GPS data is processed to obtain the tropospheric slant delays using the GIPSY-OASIS II software and define the concept of pseudo-wet delays, which will be the observables in the tomographic software. We then discuss the inverse problem in the 3D stochastic tomography, using simulated refractivity fields to test the system and the impact of noise. Finally, we use data from the Kilauea network in Hawaii and a local 4x4x41-voxel grid on a region of 400 Km2^2 and 15 Km in height to produce 4D refractivity fields. Results are compared with ECMWF forecast.Comment: 9 pages, 6 figures (2 color

    A supersymmetric exotic field theory in (1+1) dimensions. One loop soliton quantum mass corrections

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    We consider one loop quantum corrections to soliton mass for the N=1{\cal N}=1 supersymmetric extension of the (1+1)-dimensional scalar field theory with the potential U(ϕ)=ϕ2cos2(lnϕ2)U(\phi) = \phi^2 \cos^2\left(\ln \phi^2\right). First, we compute the one loop quantum soliton mass correction of the bosonic sector. To do that, we regularize implicitly such quantity by subtracting and adding its corresponding tadpole graph contribution, and use the renormalization prescription that the added term vanishes with the corresponding counterterms. As a result we get a finite unambiguous formula for the soliton quantum mass corrections up to one loop order. Afterwards, the computation for the supersymmetric case is extended straightforwardly and we obtain for the one loop quantum correction of the SUSY kink mass the expected value previously derived for the SUSY sine-Gordon and ϕ4\phi^4 models. However, we also have found that for a particular value of the parameters, contrary to what was expected, the introduction of supersymmetry in this model worsens ultraviolet divergences rather than improving them.Comment: 16 pages, 8 figures; Major modifications included to match version published in JHE
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