A new numerical algorithm for the double-orbital Hubbard model -- Hund-coupled pairing symmetry in the doped case

摘要

In order to numerically study electron correlation effects in multi-orbitalsystems, we propose a new type of discrete transformation for the exchange(Hund's coupling) and pair-hopping interactions to be used in the dynamicalmean field theory + quantum Monte Carlo method. The transformation, which isreal and exact, turns out to suppress the sign problem in a wide parameterregion including non-half-filled bands. This enables us to obtain the dominantpairing symmetry in the double-orbital Hubbard model, which shows that thespin-triplet, orbital-antisymmetric pairing that exploits Hund's coupling isstable in a wide region of the band filling.