2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/219405We study ground state properties of periodic Anderson model in a two-dimensional square lattice with variational Monte Carlo method. It is shown that there are two different types of quantum phase transition: a conventional antiferromagnetic transition and a Fermi-surface reconstruction which accompanies a change of topology of the Fermi surface. The former is induced by a simple back-folding of the Fermi surface while the latter is induced by localization of $f$ electrons. The mechanism of these transitions and the relation to the recent experiments on Fermi surface are discussed in detail.8 pages, 7 figures, submitted to Journal of the Physical Society of JapanStrongly Correlated Electronstext