2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180364The blackbody radiation in a box L^3 with periodic boundary conditions in thermal equilibrium at a temperature T is affected by finite-size effects. These bring about modifications of the thermodynamic functions which can be expressed in a closed form in terms of the dimensionless parameter LT. For instance, when LT~4 - corresponding to the value where the most reliable SU(N) gauge lattice simulations have been performed above the deconfining temperature T_c - the deviation of the free energy density from its thermodynamic limit is about 5%. This may account for almost half of the pressure deficit observed in lattice simulations at T~ 4 T_c.9 pages, 2 figures v2:a side remark on the final result and references addedHigh Energy Physics - LatticeAstrophysicsStatistical MechanicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext