  Both black hole thermodynamics and finite volume effects in quantum field
theory violate the null energy condition. Motivated by this, we compare
thermodynamic features between two 1+1-dimensional systems: (i) a scalar field
confined to a periodic spatial interval of length $a$ and tunneling between two
degenerate vacua; (ii) a dilatonic black hole at temperature $T$ in the
presence of matter fields. If we identify $a\propto T^{-1}$, we find similar
thermodynamic behaviours, which suggests some deeper connection arising from
the presence of non-trivial boundary conditions in both systems.
