Trouble getting the matrix representation of a 4-state Hamiltonian
$\newcommand{\bra}[1]{\left\langle #1 \right|} \newcommand{\ket}[1]{\left| #1 \right\rangle}$I have a simple 4-state Hamiltonian and am trying to find the matrix representation (in order to determine the eigenvalues of energy for the system); however, I keep ending up with the wrong matrix, so I'd appreciate some help with spotting what concept I'm misunderstanding. 656