Quantum path-integral method for the fictitious-particle Hubbard model
Phys. Rev. B 113, 115123 – Published 11 March, 2026
DOI: https://doi.org/10.1103/vqj6-6vyt
Abstract
We formulate a path-integral Monte Carlo algorithm for simulating lattice systems consisting of fictitious particles governed by generalized exchange statistics. This method, initially proposed for continuum systems, introduces a continuous parameter in the partition function that interpolates between bosonic and fermionic statistics. We generalize this approach to discrete lattice models and apply it to the two-dimensional Hubbard model of fictitious particles, including the Bose- and Fermi-Hubbard models as special cases. By combining reweighting and -extrapolation techniques, we access both half-filled and doped regimes. In particular, we demonstrate that the method remains effective in strongly correlated, doped systems, offering a distinct advantage by naturally operating in the canonical ensemble. Our results validate the applicability of the fictitious-particle framework to lattice models and establish it as a promising, complementary tool for investigating strongly interacting fermionic systems.