Correspondence of I- and Q-balls as Non-relativistic Condensates

Understand

If a real scalar field is dominated by non-relativistic modes, then it approximately conserves its particle number and obeys an equation that governs a complex scalar field theory with a conserved global U(1) symmetry.

• From this fact, it is shown that the I-ball (oscillon) can be naturally understood as a projection (e.g., real part) of the non-relativistic Q-ball solution.
• In particular, we clarify that the stability of the I-ball is guaranteed by the U(1) symmetry in the corresponding complex scalar field theory as long as the non-relativistic condition holds.
• We also discuss the longevity of I-ball from the perspective of the complex scalar field in terms of U(1) charge violating processes.