  The spectrum of bound states of special strongly coupled confining field
theories might include a parametrically light dilaton, associated with the
formation of enhanced condensates that break (approximate) scale invariance
spontaneously. It has been suggested in the literature that such a state may
arise in connection with the theory being close to the unitarity bound in
holographic models. We extend these ideas to cases where the background
geometry is non-AdS, and the gravity description of the dual confining field
theory has a top-down origin in supergravity.
  We exemplify this programme by studying the circle compactification of Romans
six-dimensional half-maximal supergravity. We uncover a rich space of
solutions, many of which were previously unknown in the literature. We compute
the bosonic spectrum of excitations, and identify a tachyonic instability in a
region of parameter space for a class of regular background solutions. A
tachyon only exists along an energetically disfavoured (unphysical) branch of
solutions of the gravity theory; we find evidence of a first-order phase
transition that separates this region of parameter space from the physical one.
Along the physical branch of regular solutions, one of the lightest scalar
particles is approximately a dilaton, and it is associated with a condensate in
the underlying theory. Yet, because of the location of the phase transition,
its mass is not parametrically small, and it is, coincidentally, the
next-to-lightest scalar bound state, rather than the lightest one.

High Energy Physics - Theory;High Energy Physics - Lattice;High Energy Physics - Phenomenology