Gravitational waves from first-order phase transitions: Towards model separation by bubble nucleation rate

• Published in: arXiv.org 2018-03
• Main Authors: Jinno, Ryusuke, Lee, Sangjun, Hyeonseok Seong, Takimoto, Masahiro
• Format: Article
• Language: English
• Subjects: Bubbles; Dependence; Gravitation; Gravitational waves; Nucleation; Phase transitions; Separation; Shape recognition; Tensors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1708.01253

We study gravitational-wave production from bubble collisions in a cosmic first-order phase transition, focusing on the possibility of model separation by the bubble nucleation rate dependence of the resulting gravitational-wave spectrum. By using the method of relating the spectrum with the two-point correlator of the energy-momentum tensor \(\left< T(x)T(y) \right>\), we first write down analytic expressions for the spectrum with a Gaussian correction to the commonly used nucleation rate, \(\Gamma \propto e^{\beta t}\rightarrow e^{\beta t-\gamma^2t^2}\), under the thin-wall and envelope approximations. Then we quantitatively investigate how the spectrum changes with the size of the Gaussian correction. It is found that the spectral shape shows \({\mathcal O}(10)\%\) deviation from \(\Gamma \propto e^{\beta t}\) case for some physically motivated scenarios. We also briefly discuss detector sensitivities required to distinguish different spectral shapes.