爱因斯坦狭义相对论的基本假设之一是光速不变性,其直接推论就是光子的静止质量必须为零,因此实验检验光子是否具有非零的静止质量一直备受关注,非零光子静止质量以Proca方程组为基础,其实验检验主要针对真空光速(频率)色散效应、库仑反平方定律和安培环路定律的偏离、寻找纵向电磁波以及磁偶极场的Yukawa势等几个方面。文章作者所在的实验小组采用精密扭秤调制方法将国际上同类实验结果提高了2个数量级,给出光子静止质量上限为mγ≤1.5×10^52g,对光子静止质量的实验检验,也是对光速不变原理的一种检验,即使光子仅有非常微小的静质量,如一日得到实验的检验,将会对整个物理学的发展产生巨大而深刻的影响。
One of the hypotheses of Einstein's special relativity is the constant speed of light, which directly implies that the photon should be massless, and hence experimental tests of its foundations are always of considerable interest. Based on Proca's equations, some far - reaching implications for nonzero photon mass, for example, the frequency dependence of the speed of light in free space, the deviations of Coulomb's Law and Ampere's Law, the existence of longitudinal electromagnetic waves and the additional Yukawa potential of magnetic dipole fields were seriously studied. Through use of a modulated to.ion balance our experimental measurements improved the current upper limits on the photon rest mass by at least two orders, and gave mγ≤ 1.5 × 10^-52g. Experimental investigations of the photon rest mass are an indirect test of the constancy of the speed of light, and any conclusive evidence of a finite mass for the photon will greatly affect the development of all physics.