Competition between antiferromagnetism and superconductivity -- a quantum Monte-Carlo study

The competition between antiferromagnetism (AFM) and superconductivity (SC) remains a challenging problem in condensed matter physics because of the lack of non-perturbative method to handle strong correlations. Quantum Monte Carlo (QMC) simulations often suffers from the notorious fermion sign problem. It has been found that in a multi-band Hubbard model, or, equivalently, a large-spin Hubbard model, the sign problem can be removed at arbitrary fillings in a parameter regime in which SC competes with AFM. We have performed QMC simulations to investigate the phase diagram as doping and interaction strength.