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Ultrapure glass optical waveguide development in microgravity by the sol-gel process
The alkali-borosilicate system was selected as the glass system for the preparation of ultrapure low loss glasses suitable for optical communication. The effect of different oxide contents on the absorption loss was critically reviewed. One composition was chosen to develop the gel preparation procedure in the alkali-borosilicate system. In addition, several procedures for the preparation of gels based on two different approaches were developed. The influence of different preparation parameters were investigated qualitatively. Several conclusions are drawn from the results
Ginzburg-Landau theory of noncentrosymmetric superconductors
The data of temperature dependent superfluid density in
LiPdB and LiPtB [Yuan {\it et al.}, \phrl97, 017006 (2006)]
show that a sudden change of the slope of occur at slightly lower
than the critical temperature. Motivated by this observation, we
microscopically derive the Ginzburg-Landau (GL) equations for
noncentrosymmetric superconductors with Rashba type spin orbit interaction.
Cooper pairing is assumed to occur between electrons only in the same spin
split band and pair scattering is allowed to occur between two spin split
bands. The GL theory of such a system predicts two transition temperatures, the
higher of which is the conventional critical temperature while the lower
one corresponds to the cross-over from a mixed singlet-triplet phase at
lower temperatures to only spin-singlet or spin-triplet (depending on the sign
of the interband scattering potential) phase at higher temperatures. As a
consequence, shows a kink at this cross-over temperature. We
attribute the temperature at which sudden change of slope occurs in the
observed to the temperature . This may also be associated with
the observed kink in the penetration depth data of CePtSi. We have also
estimated critical field near critical temperature.Comment: 7 pages, 1 figur
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