Updated Operators

Begin this assignment (Assignment #2) by making a directory ``$\sim$/A2'', changing into that directory and copying everything from the previous assignment into your new directory with ``cd $\sim$; mkdir $\sim$/A2; cd $\sim$/A2; cp ../A1/*.m .''. Be sure that the parameters are set in ``setup.m'' to S=[20; 25; 30] and R=diag([6 6 6]) and in ``ewald.m'' to sigma1=0.25.

Two new operators appear in the expressions, ${\bf I}^\dagger$ and ${\bf J}^\dagger$. Also, operators now sometimes act on matrices, which we view as collections of column vectors, rather than on single column vectors. We must therefore provide some new operators and generalize the ones we already have.