20.4 fitting the energy levels

We minimise the \(\chi^2\) \[ \chi^2= \sum_i \frac{( \Delta E_2^{predicted} -\Delta E_2^{latt})^2}{\sigma^2} \]

\[\begin{gather} \chi^2/d.o.f.=0.584471 \\ P[0]=-0.148051\pm (0.002) \\ P[1]=-4.06576\pm (0.19) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& 0.00154\\ 0.00154& 1\\ \end{pmatrix} \end{gather}\]}