2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/18706The quantum discrete $ϕ^4$ model at finite temperature is studied in the mean-field approximation. The phase diagrams are obtained for a wide range of the model parameters. The domains of applicability for the classical, quantum, and order-disorder limits are determined. It is shown that a remarkable part of the phase diagram is reproduced by the first quantum correction to the classical result. Parameters of Sn$_2$P$_2$S$_6$, SrTiO$_3$, and KH$_2$PO$_4$ are placed in the phase diagram of the model.3 figures, figures were changedStatistical Mechanicstext