Effective actions and bubble nucleation from holography
  We discuss the computation of the quantum effective action of strongly
interacting field theories using holographic duality, and its use to determine
quasi-equilibrium parameters of first order phase transitions relevant for
gravitational wave production. A particularly simple holographic model is
introduced, containing only the metric and a free massive scalar field. Despite
the simplicity, the model contains a rich phase diagram, including first order
phase transitions at non-zero temperature, due to various multi-trace
deformations. We obtain the leading terms in the effective action from
homogeneous black brane solutions in the gravity dual, and linearised
perturbations around them. We then employ the effective action to construct
bubble and domain wall solutions in the field theory side and study their
properties. In particular, we show how the scaling of the effective action with
the effective number of degrees of freedom of the quantum field theory
determines the corresponding scaling of gravitational wave parameters.
