论文标题
用国际脉冲星定时阵列挤压宇宙学相变
Squeezing Cosmological Phase Transitions with International Pulsar Timing Array
论文作者
论文摘要
一阶MEV尺度宇宙学相变（PT）可以在纳米氏菌频率周围的随机重力波背景的功率谱中产生峰值。随着最近的国际PULSAR正时阵列数据发布两个涵盖纳米赫兹频率的两个，我们搜索了这样的相变信号。对于标准的4参数PT模型，我们以$ [66 MEV，30 GEV]获得PT温度$ T_ \ Star \，这表明在66 MeV以下的黑暗或QCD相变已排除在$ 2 \，σ$置换水平。该约束比Nanograv的$ T_ \ star \ sim $ [1 MeV，100 GEV]更紧。我们还给PT持续时间$ H_ \ Star/β> 0.1 $，强度$α__\ Star> 0.39 $和摩擦$η<2.74 $的PT持续时间上的$ 2 \，σ$界限。我们第一次发现$ \ mathrm {log} _ {10} t_ \ star $和$ \ mathrm {log} _ {10} _ {10} h_ \ star/β$之间的正相关，暗示PT温度随着泡泡核的增加而增加。为了避免在计算PT光谱时进行大量理论不确定性，我们制作气泡频谱形状参数$ a $ a $，$ b $，$ c $和四个PT参数免费，并与数据与此模型面对数据。我们发现PULSAR时机对参数$ a $非常敏感，并给出了第一个清晰的约束$ a = 1.27 _ { - 0.54}^{+0.71} $，$ 1 \，σ$置信度级别。
A first-order MeV-scale cosmological phase transition (PT) can generate a peak in the power spectrum of stochastic gravitational wave background around nanohertz frequencies. With the recent International Pulsar Timing Array data release two covering nanohertz frequencies, we search for such a phase transition signal. For the standard 4-parameter PT model, we obtain the PT temperature $T_\star\in$ [66 MeV, 30 GeV], which indicates that dark or QCD phase transitions occurring below 66 MeV have been ruled out at $2\,σ$ confidence level. This constraint is much tighter than $T_\star\sim$ [1 MeV, 100 GeV] from NANOGrav. We also give much tighter $2\,σ$ bounds on the PT duration $H_\star/β>0.1$, strength $α_\star>0.39$ and friction $η<2.74$ than NANOGrav. For the first time, we find a positive correlation between $\mathrm{log}_{10}T_\star$ and $\mathrm{log}_{10}H_\star/β$ implying that PT temperature increases with increasing bubble nucleation rate. To avoid large theoretical uncertainties in calculating PT spectrum, we make bubble spectral shape parameters $a$, $b$, $c$ and four PT parameters free together, and confront this model with data. We find that pulsar timing is very sensitive to the parameter $a$, and give the first clear constraint $a=1.27_{-0.54}^{+0.71}$ at $1\,σ$ confidence level.
