Variational Numerical Renormalization Group: Bridging the Gap between NRG and Density Matrix Renormalization Group

Author(s): I. Pižorn, F. Verstraete

Journal: Physical Review Letters

Volume: 108

Page(s): 4 pp.

Year: 2012

DOI Number: 10.1103/PhysRevLett.108.067202

Link: Link to publication


The numerical renormalization group (NRG) is rephrased as a variational method with the cost function given by the sum of all the energies of the effective low-energy Hamiltonian. This allows us to systematically improve the spectrum obtained by NRG through sweeping. The ensuing algorithm has a lot of similarities to the density matrix renormalization group (DMRG) when targeting many states, and this synergy of NRG and DMRG combines the best of both worlds and extends their applicability. We illustrate this approach with simulations of a quantum spin chain and a single impurity Anderson model where the accuracy of the effective eigenstates is greatly enhanced as compared to the NRG, especially in the transition to the continuum limit.


File: Link to PDF

Verstraete Group Verstraete Group