H. Fotso, LSU/ETHZ
The parquet formalism is used to solve the Hubbard model on a 4x4 cluster self-consistently both at the one and two-particle levels. The results are compared to those obtained by other conserving approximations such as self-consistent second order approximation, FLuctuation EXchange approximation (FLEX), as well as Determinant Quantum Monte Carlo (DQMC). The parquet approximation is shown to have a better agreement with DQMC than the other conserving approximations. Computational difficulties of the approach are presented and solutions to these challenges are outlined.