Phase-diagram and quasiparticles of a lattice SU(2) scalar-fermion model in (2+1) dimensions
arXiv:cond-mat/9907288 · doi:10.1103/PhysRevD.61.034501
Abstract
The phase diagram at zero temperature of a lattice SU(2) scalar-fermion model in (2+1) dimensions is studied numerically and with Mean-Field methods. Special attention is devoted to the strong coupling regime. We have developed a new method to adaptate the Hybrid Monte Carlo algorithm to the O(3) non-linear $Ï$ model constraint. The charged excitations in the various phases are studied at the Mean-Field lev el. Bound states of two charged fermions are found in a strongly coupled {\it paramagnetic} phase. On the other hand, in the strongly coupled antiferromagnetic phase fermionic excitations around momenta $(\pm\fracÏ{2},\pm\fracÏ{2},\pm\fracÏ{2})$ emerge.
28 pages plus 7 postscript figures