Dynamical nonlinear optical coefficients from the symmetrized density-matrix renormalization-group method

Abstract

We extend the symmetrized density-matrix renormalization-group method to compute the dynamic nonlinear optical coefficients for long chains. By computing correction vectors in the appropriate symmetry subspace, we obtain the dynamic polarizabilities, α_ij(ω), and third-order polarizabilities γ_ijkl(ω,ω,ω) of the Hubbard and "U-V" chains in an all transpolyacetylene geometry, with and without dimerization. We rationalize the behavior of α̅ and γ̅ on the basis of the low-lying excitation gaps in the system. This is the first study of the dynamics of a fermionic system within the DMRG framework.