  We derive a material-realistic real-space many-body Hamiltonian for twisted
bilayer graphene from first principles, including both single-particle hopping
terms for $p_z$ electrons and long-range Coulomb interactions. By disentangling
low- and high-energy subspaces of the electronic dispersion, we are able to
utilize state-of-the-art constrained Random Phase Approximation calculations to
reliably describe the non-local background screening from the high-energy $s$,
$p_x$, and $p_y$ electron states for arbitrary twist angles. The
twist-dependent low-energy screening from $p_z$ states is subsequently added to
obtain a full screening model. We use this approach to study real-space
plasmonic patterns in electron-doped twisted bilayer graphene supercells and
find, next to classical dipole-like modes, also twist-angle-dependent plasmonic
quantum-dot-like excitations with $s$ and $p$ symmetries. Based on their
inter-layer charge modulations and their footprints in the electron energy loss
spectrum, we can classify these modes into "bright" and "dark" states, which
show different dependencies on the twist angle.
