Functional renormalization group for fermion lattice models in three dimensions: application to the Hubbard model on the cubic lattice

Understand

The channel-decomposed functional renormalization group (FRG) approach, most recently in the variant of truncated-unity-(TU-)FRG, has so far been used for various two-dimensional model systems.

• Yet, for many interesting material systems the third spatial dimension is of clear relevance.
• Therefore FRG schemes working in three spatial dimensions (3D) are definitely on the wishlist.
• Here we demonstrate that a 3D TUFRG scheme can be set up in straightforward extension of previous 2D codes and gives physically sensible results with affordable numerical effort, both regarding the qualitative as well as the quantitative description.