Hubble-induced phase transitions: Walls are not forever
  The interplay between non-minimally coupled scalar fields and a
kinetic-dominated era following the end of inflation triggers the spontaneous
symmetry breaking of internal symmetries and the subsequent evolution of the
fields towards large expectation values. We present here a detailed analysis of
the associated dynamics in quintessential inflation scenarios involving a
non-minimally coupled $Z_2$-symmetric spectator field. By analytically
following the evolution of the spectator field fluctuations at early times, we
characterize the formation of classical, homogeneous and spatially-localized
field configurations separated by domain walls. The life expectancy of these
dividing barriers is set by the scale of inflation, the non-minimal coupling
and self-interactions of the spectator field and potentially, but not
necessarily, the duration of the heating stage. For most of the parameter
space, the domain walls are doomed to disappear before big bang
nucleosynthesis. Potential phenomenological consequences of the scenario are
discussed.
