An Improved Two-Particle Self-Consistent Approach

Abstract

The two-particle self-consistent approach (TPSC) is a method for the one-band Hubbard model that can be both numerically efficient and reliable. However, TPSC fails to yield physical results deep in the renormalized classical regime of the bidimensional Hubbard model where the spin correlation length becomes exponentially large. We address the limitations of TPSC with improved approaches that we call TPSC+ and TPSC+SFM. In this work, we show that these improved methods satisfy the Mermin-Wagner theorem and the Pauli principle. We also show that they are valid in the renormalized classical regime of the 2D Hubbard model, where they recover a generalized Stoner criterion at zero temperature in the antiferromagnetic phase. We discuss some limitations of the TPSC+ approach with regards to the violation of the f-sum rule and conservation laws, which are solved within the TPSC+SFM framework. Finally, we benchmark the TPSC+ and TPSC+SFM approaches for the one-band Hubbard model in two dimensions and show how they have an overall better agreement with available diagrammatic Monte Carlo results than the original TPSC approach.

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Cited by in corpus (7)

• Spin Hall conductivity in the Kane-Mele-Hubbard model at finite temperature
• Real-frequency TPSC+DMFT investigation of the square-lattice Hubbard model
• Spin correlations in the bilayer Hubbard model with perpendicular electric field
• Multi-orbital two-particle self-consistent approach -- strengths and limitations
• Antiferromagnetic pseudogap in the two-dimensional Hubbard model deep in the renormalized classical regime
• Quasi-particle functional Renormalisation Group calculations in the two-dimensional t-t'-Hubbard model
• Nonpertubative Many-Body Theory for the Two-Dimensional Hubbard Model at Low Temperature: From Weak to Strong Coupling Regimes