We investigate the potential of gravitational-wave background searches to constrain cosmic histories characterized by a stiff equation of state, preceded by a period of matter domination. Such a scenario leads to a characteristic peak in the primordial gravitational-wave spectrum originating from cosmological inflation. Assuming instant transitions between distinct epochs, which allows for an analytical treatment of the gravitational-wave spectrum, we perform a Bayesian inference analysis to derive constraints from the first three observing runs of the LIGO-Virgo-KAGRA Collaboration. Additionally, we consider a smooth transition, employing an axionlike particle physics model, and highlight the differences compared to the instant transition approximation. Finally, we forecast detection prospects for such a cosmic history through future gravitational-wave experiments.

中文翻译：

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通过引力波研究僵硬时代的宇宙历史


我们研究了引力波背景搜索的潜力，以限制以僵硬状态方程为特征的宇宙历史，之前是一段物质主导时期。这种情况导致原始引力波谱中源自宇宙学膨胀的特征峰值。假设不同纪元之间存在瞬时转换，从而可以对引力波谱进行分析处理，我们进行贝叶斯推理分析，以从 LIGO-Virgo-KAGRA 合作的前三次观测运行中得出约束。此外，我们采用类似轴子的粒子物理模型考虑了平滑过渡，并强调了与瞬时过渡近似相比的差异。最后，我们通过未来的引力波实验预测了这种宇宙历史的探测前景。