  There exists an inconsistency in the value of the kinetic energies of the
antiproton in the electron laboratory reference frame and of the electron in
the antiproton laboratory reference frame taken wrongly both as 0.65 keV (see
figure 1 and table 2) of the paper. The consequence of this mistake is that the
relative velocity of the electron is not -0.0504 (see table 2) but -0.00118,
i.e. a factor of \sqrt{m_{electron}/m_{proton}} = 1/43 smaller. The consequence
of this factor is that the relative velocity \beta_{relative} in eq. (27) and
\kappa are smaller by this factor. This means that the time for polarisation
build-up is longer by a factor 43. Though the principle idea is not put into
question, the method is not effective "with todays technology" and we have to
withdraw the paper and the proposal.
