Benchmark of the TPSC+DMFT approach for the Hubbard model

The two-particle self-consistent approach (TPSC) is an effective tool for studying systems that can be modelled by a single-band Hubbard model at weak to intermediate coupling strength [1, 2]. However, the results obtained by this method on a 2D square lattice are poor in the renormalized classical regime. We show how using double-occupancy and self-energy results from single-site dynamical mean field theory (DMFT) can improve this approach, while removing the need for the TPSC ansatz. In this work, we apply the proposed method to a 2D square lattice with nearest-neighbor hopping. We benchmark our approach using Monte-Carlo results [2] for the magnetic correlation length and the self-energy.

[1] Vilk, Y. M. et Tremblay, A.-M. S. J. Phys. I France7, 1309–1368 (1997).

[2] Schäfer, T. et al.Phys. Rev. X11, 011058 (2021).