  Spacetime boundaries with canonical Neuman or Dirichlet conditions preserve
conformal invarience, but "mixed" boundary conditions which interpolate
linearly between them can break conformal symmetry and generate interesting
Renormalization Group flows even when a theory is free, providing soluble
models with nontrivial scale dependence. We compute the (Rindler) entanglement
entropy for a free scalar field with mixed boundary conditions in half
Minkowski space and in Anti-de Sitter space. In the latter case we also compute
an additional geometric contribution, which according to a recent proposal then
collectively give the 1/N corrections to the entanglement entropy of the
conformal field theory dual. We obtain some perturbatively exact results in
both cases which illustrate monotonic interpolation between ultraviolet and
infrared fixed points. This is consistent with recent work on the
irreversibility of renormalization group, allowing some assessment of the
aforementioned proposal for holographic entanglement entropy and illustrating
the generalization of the g-theorem for boundary conformal field theory.
