\sect{Baruch's C26.}
${N}$ ions of positive charge ${q}$ and ${N}$ with negative
charge ${-q}$ are constrained to move in a two dimensional square
of side ${L}$. The interaction energy of charge ${q_{i}}$ at
position ${{\bf r}_{i}}$ with another charge ${q_{j}}$ at ${{\bf
r}_{j}}$ is $-q_{i}q_{j} \ln|{\bf r}_{i}-{\bf r}_{j}|$ where
${q_{i},q_{j}=\pm q}$. The Hamiltonian is then ($m$ is the mass of each ion and ${\bf p}_i$ are momenta)
\[ {\cal H}=\sum_{i=1}^{2N}{\bf p}_i^2/2m - \sum_{iT_c=q^2/4$ and $T