Coset space construction for the conformal group: Spontaneously broken phase and inverse Higgs phenomenon

We establish a mathematically rigorous way to construct effective theories resulting from the spontaneous breaking of conformal invariance. We show that the Nambu–Goldstone field corresponding to spontaneously broken generators of special conformal transformations is always a nondynamical degree of freedom. We prove that the developed approach and the standard approach including application of the inverse Higgs mechanism are equivalent.