The truncated polynomial expansion Monte Carlo method for fermion systems coupled to classical fields: a model independent implementation

Method of solution: Typically an exact diagonalization of the electronic sector is performed in this type of models for each configuration of classical fields, which are integrated using a classical Monte Carlo algorithm. A polynomial expansion of the density of states is able to replace the exact diagonalization, decreasing the computational complexity of the problem from O(N4) to O(N) and allowing for the study of larger lattices and more complex and realistic systems.