Does a phase transition in the early universe produce the conditions needed for inflation\?
Abstract
In the standard ``new inflationary scenario,'' it is assumed that when the Higgs field φ is cooled below its phasetransition temperature T_{c} it is found in a metastable state which has negligible kinetic and spatialderivative energy but has large, positive potential energy V_{0}. Hence, in this picture, the stressenergy tensor of φ is of the form T_{ab}=V_{0}g_{ab} and remains of this form until the state becomes unstable and ``rolls down the hill'' to its true minimum at φ=φ_{c}. With this stressenergy tensor Einstein's equation for a RobertsonWalker model predicts expansion of the universe on an exponential time scale, i.e., inflation. We argue here that, at least in many possible models this standard picture of the behavior of φ as it is cooled to T_{c} and below is wrong. Rather than be ``supercooled'' to a state with φ~=0 locally, the field should rapidly form domains with φ near +/φ_{c}. The dynamics of the phase transition is governed by the growth and coalescence of these domains, not by a ``roll down the hill'' of the spatially averaged value of φ. Furthermore, the stressenergy tensor of φ does not take the form needed to produce inflation. Our arguments are based mainly on physical reasoning, but they are supported by the known behavior of certain condensedmatter systems. We believe that our description of dynamical behavior near the phase transition is applicable to a wide class of fieldtheory models considered in inflationin particular, to models where φ is not coupled to other fields and ColemanWeinberg gaugecoupled models with g^{2}~1although precise criteria for the applicability of our arguments have not been obtained.
 Publication:

Physical Review D
 Pub Date:
 January 1985
 DOI:
 10.1103/PhysRevD.31.273
 Bibcode:
 1985PhRvD..31..273M
 Keywords:

 98.80.Bp;
 11.15.Bt;
 Origin and formation of the Universe;
 General properties of perturbation theory