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

Autor(en)

Iztok Pizorn, Frank Verstraete

Abstrakt

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.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Journal

Physical Review Letters

Band

108

Anzahl der Seiten

4

ISSN

0031-9007

DOI

https://doi.org/10.1103/PhysRevLett.108.067202

Publikationsdatum

02-2012

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/8513cc6b-c26f-43f9-be10-b02a5d513a77