Radiative corrections and instability of large Q-balls

Abstract

We discuss stability of Q-balls interacting with fermions in theory with small coupling constant g. We argue that for configurations with large global U (1)-charge Q the problem of classical stability becomes more subtle. For example, in model with flat direction there is maximal value of charge for stable solutions with Q ∼ 1 g 4 . This result may be crucial for the self-consistent consideration of Q-ball evaporation into the fermions. We study the origin of additional instability and discuss possible ways to avoid it.

Review of Nontopological Solitons in Theories with U(1)-Symmetry

“…In particular, one can discuss stability against tunneling into an energetically more favorable state [56,57]. By introducing the interaction of the soliton with other fields, one can ask if it evaporates into quanta of those fields [58,59], or if thermal fluctuations drive the system out of a local minimum of the energy where the soliton is located [49], or if radiative corrections to the scalar potential change it so that instability appears [60]. In the remainder of this section, we will focus on the linear classical stability of Q-balls and homogeneous condensates.…”