In this paper, the authors consider a real scalar field theory in d-dimensional flat Minkowski space-time, with the action given by
S=∫ddx[12(∂μϕ)2−U(ϕ)],
where
U(x) is a general self-interaction potential. Then, the authors proceed by saying that for the standard
ϕ4 theory, the interaction potential can be written as
U(ϕ)=18ϕ2(ϕ−2)2.
Why is this so? What is the significance of the cubic term present?
In this question Willie Wong answered by setting ψ=ϕ−1, why is that? Or why is this a gauge transformation?
Does anyone have better argument to understand the interection potential?
This post imported from StackExchange Physics at 2014-03-22 17:08 (UCT), posted by SE-user Unlimited Dreamer