We discuss the possible role of non-topological solitons (Q-balls) during first-order phase transitions in the early Universe. We argue that Q-balls cannot mediate such a transition unless the self-coupling in the effective potential is large, in which case the tunnelling probability is in any case high. A corollary of our analysis is that Q-balls do not solve the entropy problems of flat potentials such as those of Coleman and Weinberg, no-scale models and superstring models with intermediate scales. We also comment on other problems of superstring models with intermediate scales.
Bibliographical noteFunding Information:
The work of K E was supported in part by the Emil Altonen Foundation The work of D V N was supported in part by DOE grant DE-AC02-76ER-0081 and in part by the University of Wisconsin Research Committee with funds granted by the Wisconsin Alumni Research Foundation The work ofK A O was supported in part by DOE grant DE-AC02-83ER-40105 and by a Presidential Young Investigator Award