Abstract

Model reduction using localized bases and DMRG

Steve White
University of California, Irvine (UCI)

I will describe two different projects which relate to model reduction. In the first, we used sliced basis sets to simulate hydrogen chains using DMRG. The sliced bases are defined by a uniform grid in the longitudinal direction and 2D gaussian-type bases in the transverse directions. The slicing yields a partially diagonal two electron interaction and also improves DMRG convergence. From the DMRG-calculated natural orbitals, we construct Wannier functions and derive reduced model Hamiltonians. We compare the ground states of the models with the sliced basis DMRG. In the second project, we have been developing gausslet bases which have fully diagonal Hamiltonians and are localized in 3D. I will report on our latest efforts to make these bases as small as possible while maintaining high accuracy.