Spectrum of a path propagation Hamiltonian (source code)

= Spectrum of a path propagation Hamiltonian
{title2=$\lambda_k=1-\cos[\pi k/(T+1)]$}

For a path with $T+1$ vertices and edge weight $1/2$, the <eigenvalues> are $1-\cos[\pi k/(T+1)]$, $k=0,\ldots,T$. The corresponding coefficients are proportional to $\cos[\pi k(t+1/2)/(T+1)]$. The zero mode is uniform, and the <spectral gap> is at least $2/(T+1)^2$. The endpoint difference equations use reflecting ghost values, not periodic ones.