\documentclass[10pt]{article} \usepackage{graphicx, multicol,wrapfig,exscale,epsfig,fancybox,fullpage} \pagestyle{empty} \parindent=0pt \parskip=.1in \newcommand\hs{\hspace{6pt}} \begin{document} \centerline{\bf System of two spin-$\frac{1}{2}$ particles} \bigskip \underline{Small white board questions:} \begin{enumerate} \item The electron has spin $\frac{1}{2}$, with spin up and spin down eigenstates $\vert \pm \rangle_{e}$. For the electron, use the symbol $S$ for the spin $S_{e}$. Write down the eigenvalue equations for the electron states. \item The proton has spin $\frac{1}{2}$, with spin up and spin down eigenstates $\vert \pm \rangle_{e}$. For the proton, use the symbol $I$ for the spin $S_{p}$. \item Write down the eigenvalue equations for the proton states. \item The system of electron and proton could be in the state: $$ \vert e^{-} \: up \rangle \vert p^{+} \: up \rangle = \vert + \rangle_{e} \vert + \rangle_{p} \equiv \vert + + \rangle $$ Using the compact $\vert + + \rangle$ notation, what are the possible spin states of the electron-proton system? \end{enumerate} \underline{Large white board activities:} \begin{enumerate} \item Find the matrix representation of the electron spin component operator $S_{z}$ . \item Find the matrix representation of the proton spin component operator $I_{z}$. \end{enumerate} \vfill \leftline{\textit{ by David McIntyre}} \leftline{copyright DATE David McIntyre} \end{document}