Raising the Bose-Einstein condensation critical temperature using vacancies

We have studied the thermodynamic properties of an Ideal Bose gas confined within a semi-infinite box with periodic permeable multilayers [1], in particular we have calculated its BEC critical temperature and isochoric specific heat, where we have always observed a critical temperature $T_c$ smaller than the BEC critical temperature ($T_0$) of an infinite homogeneous ideal Bose gas. However, when we introduce a plane vacancy, a finite gap between the ground and first excited states in the particle energy spectrum is introduced, which increases the critical temperature beyond $T_0$ and generates a specific heat jump at $T_c$. We expect that these vacancies could lead to a raise in the critical temperature of superfluids within lattice structures. \noindent [1] P. Salas, et al., PRA {\bf 82}, 033632(2010); O.A. Rodr\'iguez, et al., J. Low Temp. Phys. {\bf 183}, 144 (2016); V.E. Barragan, et al., Int. J. Mod. Phys. B {\bf 30}, 1650099 (2016). \noindent We acknowledge partial support from grants PAPIIT IN107616 and CONACyT 221030.