  The variational local moment approach (VLMA) solution of the single impurity
Anderson model is presented. It generalizes the local moment approach of Logan
et al. by invoking the variational principle to determine the lengths of local
moments and orbital occupancies. We show that VLMA is a comprehensive,
conserving and thermodynamically consistent approximation and treats both Fermi
and non-Fermi liquid regimes as well as local moment phases on equal footing.
We tested VLMA on selected problems. We solved the single- and multi-orbital
impurity Anderson model in various regions of parameters, where different types
of Kondo effects occur. The application of VLMA as an impurity solver of the
dynamical mean-field theory, used to solve the multi-orbital Hubbard model, is
also addressed.
