\documentstyle[preprint,eqsecnum,aps]{revtex}
\tightenlines
%\documentstyle[eqsecnum,aps]{revtex}
\input epsf
\def\btt#1{{\tt$\backslash$#1}}
\def\BibTeX{\rm B{\sc ib}\TeX}
\begin{document}
\draft
%auto-ignore
This paper has been withdrawn by the authors, and instead we have 
replaced  by this new version.
\end{document}


