2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/181576The usual path integral formulation for scalar particles at finite density involves a sign problem, making numerical simulation impractical. We present alternative methods free of this difficulty. We apply these approaches to phi^4 theory in 2+1 dimensions, presenting preliminary numerical results for physical quantities in the vicinity of the phase transition in the T-mu plane.7 pages, 5 figures, talk presented at Lattice 2006 (High Temperature and Density)High Energy Physics - Latticetext