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J. E. McCarthy

Publications and source records attributed to J. E. McCarthy.

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Positivity aspects of the Fantappie transform

A Hilbert space approach to the classical Fantappie transform, based on the concept of Gel'fand triples of locally convex spaces, leads to a novel proof of Martineau-Aizenberg duality theorem. A study of Fantappie transforms of positive measures on the unit ball in $\C^n$ relates ideas of realization theory of multivariate linear systems, locally convex duality and pluripotential theory. This is applied to obtain von Neumann type estimates on the joint numerical range of tuples of Hilbert space operators.

math.FA

Induced spin polarisation in a ferromagnetic gadolinium-yttrium alloy

The first direct evidence of an induced spin moment in Gd(62.4)Y(37.6) is presented. This additional moment, of 0.16 +/- 0.03 Bohr magnetons, arises from polarisation of Y electrons in the alloy. The moment was detected in a Compton scattering experiment via the measurement of the one dimensional projection of the momentum space electron spin density in Gd and in the alloy. The result is consistent with theoretical predictions calculated using the LMTO method within the local spin density approximation.

cond-mat