Single particle flat bands
The single-electron Hamiltonian on spherical surface with a magnetic monopole of strength Q at the center of the sphere is15
$${\hat{H}}_{k}=\frac{{{\bf{L}}}^{2}-{\hslash }^{2}{Q}^{2}}{2{m}_{{\rm{e}}}{R}^{2}},$$
…
Flat bands on a spherical surface from Landau levels to giant-quantum-number orbitals
