Determine the role of parametric resonance in Chern–Simons production

Determine whether parametric resonance occurs in the post-transition oscillations of the singlet scalar field and quantify its importance for enhancing Higgs fluctuations, Higgs winding, and Chern–Simons number production in the two-field supercooled phase-transition model.

Background

The simulations show efficient Chern–Simons number production even for strongly non-degenerate vacua. After the phase transition, the singlet field oscillates around its true-vacuum value and modulates the effective Higgs mass through its coupling to the Higgs sector. These oscillations could transfer energy into Higgs fluctuations through parametric resonance, thereby facilitating the formation of Higgs winding and Chern–Simons number.

The simulations do not resolve whether this resonance actually occurs or how quantitatively important it is. Establishing its occurrence and contribution would clarify the mechanism responsible for the observed topological production in the strongly supercooled regime.

References

While our present simulations do not establish the occurrence or quantitative importance of parametric resonance, the results suggest that post-transition dynamics can play an important role in Chern-Simons number production even for highly non-degenerate vacua.

— Toward Simulations of Cold Baryogenesis via Supercooled Phase Transitions  (2610.09257 - Kitajima et al., 7 Oct 2026) in Section 3.3.3, “Generated baryon asymmetry”