87,463 research outputs found

    Effective potentials for atom-atom interaction at low temperatures

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    We discuss the concept and design of effective atom-atom potentials that accurately describe any physical processes involving only states around the threshold. The existence of such potentials gives hope to a quantitative, and systematic, understanding of quantum few-atom and quantum many-atom systems at relatively low temperatures.Comment: 4 pages, 4 figure

    On the sine-Gordon--Thirring equivalence in the presence of a boundary

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    In this paper, the relationship between the sine-Gordon model with an integrable boundary condition and the Thirring model with boundary is discussed and the reflection RR-matrix for the massive Thirring model, which is related to the physical boundary parameters of the sine-Gordon model, is given. The relationship between the the boundary parameters and the two formal parameters appearing in the work of Ghoshal and Zamolodchikov is discussed.Comment: 14 pages, Latex, to be published in Int. J. Mod. Phys. A. Two references adde

    Does Contextualism Hinge on A Methodological Dispute?

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    In this entry, we provide an overview of some of the methodological debates surrounding contextualism and consider whether they are, in effect, based on an underlying methodological dispute. We consider three modes of motivation of epistemic contextualism including i) the method of cases, ii) the appeal to linguistic analogies and iii) the appeal to conceptual analogies and functional roles. We also consider the methodological debates about contextualism arising from experimental philosophy. We conclude that i) there is no distinctive methodological doctrine or set of methodological doctrines that is centrally invoked by all epistemic contextualists and ii) the substantive dispute about the truth of contextualism very frequently, although not invariably, reflects an underlying methodological dispute

    Phases and phase stabilities of Fe3X alloys (X=Al, As, Ge, In, Sb, Si, Sn, Zn) prepared by mechanical alloying

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    Mechanical alloying with a Spex 8000 mixer/mill was used to prepare several alloys of the Fe3X composition, where the solutes X were from groups IIB, IIIB, IVB, and VB of the periodic table. Using x-ray diffractometry and Mössbauer spectrometry, we determined the steady-state phases after milling for long times. The tendencies of the alloys to form the bcc phase after milling are predicted well with the modified usage of a Darken–Gurry plot of electronegativity versus metallic radius. Thermal stabilities of some of these phases were studied. In the cases of Fe3Ge and Fe3Sn, there was the formation of transient D03 and B2 order during annealing, although this ordered structure was replaced by equilibrium phases upon further annealing
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