Testing The Constrained-Path Quantum Monte Carlo Method Using A One Dimensional Three Orbital Hubbard Model.

The ``sign problem'' usually prevents the large scale quantum Monte Carlo simulations of the multi-orbital Hubbard models. Projecting from a variety of initial states constructed via the Hartree-Fock technique, a constrained-path quantum Monte Carlo [1] (CPQMC) simulation has been carried out for the full one-dimensional three-orbital Hubbard model [2] and also for the same model but neglecting the pair-hopping and spin-flip interactions. The corresponding phase diagrams varying electronic density n and Hubbard U are constructed. Extensive comparisons with density matrix renormalization group and determinant quantum Monte Carlo results demonstrate that CPQMC is capable of capturing the physics of the orbital-selective Mott phase [2,3]. Our results also suggest that the spin-flip and pair-hopping interactions only have a limited effect on multi-orbital Hubbard model phase diagrams. [1] Guangkun Liu, Zhongbing Huang, and Yongjun Wang, J. Phys.: Condens. Matter 26, 325601(2014) [2] Julian Rincon, Adriana Moreo, Gonzalo Alvarez, and Elbio Dagotto, Phys. Rev. Lett. 112 106405 (2014) [3] Julian Rincon, Adriana Moreo, Gonzalo Alvarez, and Elbio Dagotto, Phys. Rev. B 90 241105(R)(2014)