Solution (source code)

= Solution

Distinct <eigenvalues> of a <Hermitian matrix> have <orthogonal> <eigenvectors>, since $\lambda_2e_1^\dagger e_2=e_1^\dagger He_2=\lambda_1e_1^\dagger e_2$. The given normalization then gives
$$
\boxed{e_1^\dagger(e_1+e_2)=1+0=1.}
$$