2025/11/09 by Sui, Xiao-Bin, Liu, Jing, Cai, Rong-Gen · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Pulsars and Gravitational Waves Research #Dark Matter and Cosmic Phenomena
paper · doi:10.48550/arxiv.2511.06421
We propose a novel mechanism where a first-order phase transition modulates the decay rate of a massive field. This modulation, even if the scalar field has negligible energy density, subsequently generates an observable stochastic gravitational-wave background. The stochastic nature of bubble nucleation leads to the asynchrony of phase transitions, generating superhorizon-scale density perturbations through spatial variations in the decay rate Γ. These perturbations subsequently source second-order gravitational waves with peak amplitudes governed by the phase transition parameter \(β/H_*\) and decay rate Γ. We apply this mechanism in the reheating scanario where the decay rate of inflaton are modulated by the scalar field that undergoes a first-order phase transition. Numerical calculations reveal that the gravitational wave energy spectrum typically reaches \(ΩGW ∼ 10-10\), demonstrating prospects for detection by space-based interferometers like LISA, TianQin and Taiji. This work establishes a new approach to probe phase transition processes in the early Universe without requiring significant vacuum energy release.