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

Shiro Sakai·Ryotaro Arita·Hideo Aoki
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Abstract

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

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Shiro Sakai, Ryotaro Arita, Hideo Aoki. 2004-05-21. A new numerical algorithm for the double-orbital Hubbard model -- Hund-coupled pairing symmetry in the doped case. https://doi.org/10.1103/physrevb.70.172504

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