It is well known that for some kind of double well potentials, there are two minima with one is unstable called the false vacuum while the other stable one called the true vacuum. The tunneling is allowed by quantum mechanics which is also called the false vacuum decay followed by the nucleation of bubbles. Colemann proved that the energy mostly locate on the bubble's wall. Now comes the question, what's the bublle's wall made up of? Since we always consider Higgs field, are they Higgs particles?
Inspired by the following discussions, I now know that there are no real particles associated with a static field. Because from the classical point of view, a real particle is an oscillation mode which we call plane wave. The static field may be treated as the a sea of virtual particles from the point of view of Fourier transformation. So are the domain walls.