The Gutzwiller variational approach to correlated systems: study of three significant cases

Nicola Lanatà

Jörg Bünemann, Thorben Linneweber, Florian Gebhard

The minimum of the Gutzwiller energy functional depends on the number of parameters considered in the variational state. For a three-orbital Hubbard model we find that the frequently used diagonal Ansatz is very accurate in high-symmetry situations. For lower symmetry, induced by a crystal-field splitting or the spin-orbit coupling, the discrepancies in energy between the most general and a diagonal Gutzwiller Ansatz can be quite significant. We discuss approximate schemes that may be employed in multi-band cases where a minimization of the general Gutzwiller energy functional is too demanding numerically.

Franjo Franjic

Jörg Bünemann, Thorben Linneweber, Florian Gebhard

Abstract The minimum of the Gutzwiller energy functional depends on the number of parameters considered in the variational state. For a three‐orbital Hubbard model, we find that the frequently used diagonal Ansatz is very accurate in high‐symmetry situations. For lower symmetry, induced by a crystal‐field splitting or the spin–orbit coupling, the discrepancies in energy between the most general and a diagonal Gutzwiller Ansatz can be quite significant. We discuss approximate schemes that may be employed in multi‐band cases where a minimization of the general Gutzwiller energy functional is too demanding numerically.

Hendrik Johan Eskes

Adolfo Avella, Ferdinando Mancini