Variational Monte Carlo study of electron differentiation around mott transition

We study ground-state properties of the two-dimensional Hubbard model at half filling by improving variational Monte Carlo method and by implementing quantum-number projection and multi-variable optimization. The improved variational wave function enables a highly accurate description of the Mott transition and strong fluctuations in metals. We clarify how anomalous metals appear near the first-order Mott transition. The double occupancy stays nearly constant as a function of the on-site Coulomb interaction in the metallic phase near the Mott transition in agreement with the previous unbiased results. This unconventional metal at half filling is stabilized by a formation of electron-like pockets coexisting with an arc structure, which leads to a prominent differentiation of electrons in momentum space. Ail abrupt collapse of' the pocket and arc drives the first-order Mott transition.