Determinantal Quantum Monte Carlo solver for Cluster Perturbation Theory

Cluster Perturbation Theory (CPT) is a technique for computing the spectral function of fermionic

models with local interactions. By combining the solution of the model on a finite cluster with perturbation

theory on intra-cluster hoppings, CPT provides access to single-particle properties with

arbitrary momentum resolution while incurring low computational cost. Here, we introduce Determinantal

Quantum Monte Carlo (DQMC) as a solver for CPT. Compared to the standard solver,

exact diagonalization (ED), the DQMC solver reduces finite size effects through utilizing larger

clusters, allows study of temperature dependence, and enables large-scale simulations of a greater

set of models. We discuss the implementation of the DQMC solver for CPT and benchmark the

CPT+DQMC method for the attractive and repulsive Hubbard models, showcasing its advantages

over standard DQMC and CPT+ED simulations.