2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42879The thermodynamics of the O(N) nonlinear sigma model in 1+1 dimensions is studied. We calculate the finite temperature effective potential in leading order in the 1/N expansion and show that at this order the effective potential can be made finite by temperature independent renormalization. We will show that this is not longer possible at next-to-leading order in 1/N. In that case one can only renormalize the minimum of the effective potential in a temperature independent way, which gives us finite physical quantities like the pressure.8 pages, 2 figures, Seminar talk given at the 43st Cracow School of Theoretical Physics, 30 May - 8 June 2003, Zakopane, PolandHigh Energy Physics - Phenomenologytext