Finite-Size Effects with Boundary Conditions on Bose-Einstein Condensation

We investigate the statistical distribution for ideal Bose gases with constant particle density in the 3D box of volume $V=L^3$. By changing linear size $L$ and imposing different boundary conditions on the system, we present a numerical analysis on the characteristic temperature and condensate fraction, and find that the smaller linear size is efficient to increase the characteristic temperature and condensate fraction. Moreover, there is a singularity under the antiperiodic boundary condition.