  In gravitational Higgs mechanism graviton components acquire mass in the
process of spontaneous breaking of diffeomorphisms (via scalar vacuum
expectation values). Recently, gravitational Higgs mechanism was discussed in
the context of obtaining massive gravity directly in four dimensions. We
discuss a setup, with all diffeomorphisms spontaneously broken by scalars,
where gravitational Higgs mechanism results in massive gravity in Minkowski
space with no non-unitary propagating modes. This is achieved by including
higher derivative terms in the scalar sector. Decoupling the non-unitary mode
(trace of the graviton) then requires tuning a single parameter, namely, the
cosmological constant. We also discuss a setup where only spatial
diffeomorphisms are broken. In this case we obtain massive gravity in Minkowski
space with only transverse modes propagating, so the mode count is the same as
for a massless graviton.
