Density-matrix renormalization-group study of excitons in dendrimers

We introduce the density-matrix renormalization-group method as an efficient computational tool for one-exciton approximations with off-diagonal disorder (single-particle problems). This method allows us to reduce the computational effort by targeting only a few low-lying eigenstates at each statistical sampling, in contrast to the exact diagonalization methods that compute the whole spectrum. As an application of the method, we study excitons in two families of branched molecules called dendrimers using a recently introduced simple model. We compute the absorption peaks for these dendrimers varying their generation number g and number of wedges w.