Superconductivity and Quantum Spin Disorder in Cuprates

A fundamental connection between superconductivity and quantum spin fluctuations in underdoped cuprates, is revealed. A variational calculation shows that {\em Cooper pair hopping} strongly reduces the local magnetization $m_0$. This effect pertains to recent neutron scattering and muon spin rotation measurements in which $m_0$ varies weakly with hole doping in the poorly conducting regime, but drops precipitously above the onset of superconductivity

Effects of Substituting Calcium for Yttrium on the Superconducting Properties of YBa2Cu3Oz Bulk Samples

We report systematic studies of AC magnetic susceptibility and transport properties of Y(1-x)Ca(x)Ba2Cu3Oz bulk samples with 0\leq x\leq 0.4. Single phase materials, reduction of carrier concentration and decrease of Tc to 85 K were obtained at doping levels up to 20%. For Y0.7Ca0.3Ba2Cu3Oz sample the improvement of grains boundary transport and screening capabilities has been observed as a result of the optimal ratio between carrier concentration and impurity phase BaCuO2 presence. The appearence of bulk pinning and nonlinear effects starting at the highest temperature were detected also.Comment: 12 pages, 8 figures, accepted in Physica

Colour distribution in hadron-hadron scattering

In high p/sub t/ quark-quark scattering a simple picture emerges for the colour distribution in the final state: the scattered quark of the incident hadrons forms a colour singlet with the spectators of the other hadron, i.e., the four fast coloured objects form two singlets. The author assumes that the decay of each colour singlet pair-apart from a trivial boost-is similar to that observed in deep inelastic lepton-hadron scattering. This picture leads to measurable anticorrelations for energy fluxes carried by low momentum particles. The predicted asymmetry is significant only in qq scattering, but not in qq, qg,... scattering, which leads to specific predictions. (9 refs)

Autonomic indices of pain thresholds influenced through vicarious instigation

BIbliography: p. 82-89

Determination of λ and κ in a mosaic of single crystal YBa₂Cu₃O_6.95

We present transverse field μSR measurements of the magnetic field distribution in a mosaic of single crystal YBa2Cu3O6.95 in high fields (1.9-6.5 T) applied parallel to the crystallographic c-axis. The μSR lineshapes are shown in detail and the results of fits to the lineshapes are summarized.</p

Determination of λ and κ in a mosaic of single crystal YBa₂Cu₃O_6.95

We present transverse field μSR measurements of the magnetic field distribution in a mosaic of single crystal YBa2Cu3O6.95 in high fields (1.9-6.5 T) applied parallel to the crystallographic c-axis. The μSR lineshapes are shown in detail and the results of fits to the lineshapes are summarized.</p