Probing the equation of state of the early Universe with pulsar timing arrays
Probing the equation of state of the early Universe with pulsar timing arrays
复制标题
DOI：
10.1088/1475-7516/2023/11/071
复制
发表时间：
2023-07
影响因子：
6.4
通讯作者：
Lang Liu;Zu-Cheng Chen;Q. Huang
中科院分区：
文献类型：
--
作者：
Lang Liu;Zu-Cheng Chen;Q. Huang
脉冲星定时阵列（PTA）合作最近发布的数据已经积累了大量的证据，证实存在一个随机信号，与纳赫兹附近频率的引力波背景一致。我们调查的情况下，PTA信号起源于标量诱导引力波（SIGW），这是一个有价值的工具，探测宇宙的早期阶段的状态方程参数w。综合考虑NANOGrav 15年数据集、PPTA DR 3和EPTA DR 2的PTA数据，得出w = 0.60+0.32 - 0.39（中位数+90%可信区间），表明数据允许在SIGW生产期间存在凝析油占主导地位的时期。此外，数据还支持在90%可信区间内的辐射优势（w = 1/3）。我们还对再加热温度T rh <$0.2 GeV施加了一个上限，对w的约束揭示了有关暴胀势和暴胀结束时动力学的有价值的信息。
The recently released data by pulsar timing array (PTA) collaborations have amassed substantial evidence corroborating the existence of a stochastic signal consistent with a gravitational-wave background at frequencies around the nanohertz regime. We investigate the situation in which the PTA signal originates from scalar-induced gravitational waves (SIGWs), which serves as a valuable tool to probe the equation of state parameter w during the Universe's early stages. The joint consideration of the PTA data from the NANOGrav 15-year data set, PPTA DR3, and EPTA DR2 yields that w = 0.60+0.32 -0.39 (median + 90% credible interval), indicating a period of condensate domination at the production of SIGWs is allowed by the data. Moreover, the data also supports radiation domination (w = 1/3) within the 90% credible interval. We also impose an upper bound on the reheating temperature that T rh ≲ 0.2 GeV and the constraint on w reveals valuable information on the inflationary potential and the dynamics at the end of inflation.