Fermionic two-loop functional renormalization group for correlated fermions: Method and application to the attractive Hubbard model | |
Article | |
关键词: COHERENCE LENGTH SUPERCONDUCTORS; MEAN-FIELD THEORY; SPIN GAP; SELF-CONSISTENT; GROUP FLOWS; SYSTEMS; QUANTUM; SYMMETRY; BEHAVIOR; LATTICE; | |
DOI : 10.1103/PhysRevB.90.115125 | |
来源: SCIE |
【 摘 要 】
We derive an efficient method for treating renormalization contributions at two-loop level within the functional renormalization group in the one-particle irreducible formalism for fermions. It is based on a decomposition of the two-particle vertex in charge, magnetic and pairing channels. The method treats single-particle and collective excitations in all channels on equal footing, allows for the description of symmetry breaking and captures collective mode fluctuation physics in the infrared. As a first application, we study the superfluid ground state of the two-dimensional attractive Hubbard model. We obtain superfluid gaps that are reduced by fluctuations in comparison to the one-loop approximation and demonstrate that the method captures the renormalization of the amplitude mode by long-range phase fluctuations.
【 授权许可】
Free