In Einstein's general relativity (GR), gravity is described by a massless spin-2 metric field, and the extension of GR to include a mass term for the graviton has profound implication for gravitation and cosmology. Besides the gravity experiments carried out in the Solar System and those recently with gravitational waves (GWs), pulsar timing observations provide a complementary means to test the masslessness of graviton. In this contribution, I overview three methods in probing the mass of graviton from precision timing of binary pulsars via the modified gravitational radiation (hence, the observed damping rate of the orbital period), as well as from the pulsar-timing-array (PTA) experiments via the modified Hellings-Downs angular-correlation curve. These tests probe different aspects of gravitation in its kinematics and dynamics, complementing tests of other kinds and providing valuable information to the fundamental theory of gravity.

中文翻译：

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引力子质量的脉冲星测试

在爱因斯坦的广义相对论 (GR) 中，重力由无质量自旋 2 度量场描述，GR 的扩展包括引力子的质量项对引力和宇宙学具有深远的意义。除了在太阳系中进行的重力实验和最近使用引力波 (GW) 进行的实验外，脉冲星计时观测还提供了测试引力子无质量的补充手段。在这篇文章中，我概述了通过修正的引力辐射（因此，观测到的轨道周期阻尼率）以及脉冲星计时阵列（PTA）从双脉冲星的精确计时中探测引力子质量的三种方法) 通过修改后的 Hellings-Downs 角相关曲线进行实验。这些测试探讨了引力在运动学和动力学方面的不同方面，