(2015-12-15) Alberto, Pedro; Das, Saurya; Vagenas, Elias C.
We generalize the work of Alberto, Fiolhais and Gil and solve the problem of a Dirac particle
confined in a 3-dimensional box. The non-relativistic and ultra-relativistic limits are considered
and it is shown that the size of the box determines how relativistic the low-lying states are. The
consequences for the density of states of a relativistic fermion gas are briefly discussed.