The circular polarization of the stochastic gravitational wave background (SGWB) is a key observable for characterizing the origin of the signal detected by Pulsar Timing Array (PTA) collaborations. Both the astrophysical and the cosmological SGWB can have a sizeable amount of circular polarization, due to Poisson fluctuations in the source properties for the former, and to parity violating processes in the early universe for the latter. Its measurement is challenging since PTA are blind to the circular polarization monopole, forcing us to turn to anisotropies for detection. We study the sensitivity of current and future PTA datasets to circular polarization anisotropies, focusing on realistic modelling of intrinsic and kinematic anisotropies for astrophysical and cosmological scenarios respectively. Our results indicate that the expected level of circular polarization for the astrophysical SGWB should be within the reach of near future datasets, while for cosmological SGWB circular polarization is a viable target for more advanced SKA-type experiments.

中文翻译：

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使用脉冲星计时阵列测量引力波的圆极化


随机引力波背景 （SGWB） 的圆极化是表征 Pulsar Timing Array （PTA） 合作检测到的信号来源的关键可观测对象。天体物理学和宇宙学 SGWB 都可以具有相当大的圆极化，这是由于前者源属性的泊松波动，而后者是由于早期宇宙中违反奇偶性的过程。它的测量具有挑战性，因为 PTA 对圆极化单极子视而不见，迫使我们转向各向异性进行检测。我们研究了当前和未来的 PTA 数据集对圆极化各向异性的敏感性，分别专注于天体物理学和宇宙学情景的本征和运动各向异性的现实建模。我们的结果表明，天体物理学 SGWB 的预期圆极化水平应该在不久的将来数据集的范围内，而对于宇宙学 SGWB 来说，圆极化是更高级 SKA 类型实验的可行目标。