旋转物体的等效原理及其空间实验

Equivalence principle for a rotating body and its test in space

文章回溯了等效原理的历史,解释了弱等效原理(伽利略等效原理)、强等效原理(爱因斯坦等效原理)和甚强等效原理.实验检验表明,到10-13的实验精度时,没有观测到等效原理的破坏.文章最后,也是文章的主要目的,阐述了广义相对论的不足,即不能描写物质的自旋与引力场的耦合.自旋粒子或自转物体的能-动张量既有对称分量,也有非对称的分量,还有自旋张量.但是广义相对论的引力场方程中只包含了能-动张量对称分量,不包含反对称分量,更没有自旋张量的贡献.涉及自旋与引力场耦合的理论是(有挠率场的)引力规范理论,该理论预言:自旋粒子或旋转物体将偏离测地运动,因而破坏等效原理.为了检验这种破坏,文章作者及其合作者建议进行地面实验和空间实验.

The history of the equivalence principle（EP） is reviewed,and the weak EP（Galileo′s EP）,strong EP（Einstein′s EP）,and very strong EP are explained.Experiments show that EP has not been violated up to an experimental accuracy of 10-13.In the last part of the paper we point out the insufficiency of general relativity,which cannot describe the coupling between the spin of matter and the gravitational field.As we know,a spin particle or a rotating body can be characterized by an asymmetric energy-momentum tensor and a spin tensor.However,the gravitational field equations in general relativity only involve the symmetric components but not the asymmetric part of the former tensor,nor are there any contributions from the latter tensor.On the other hand,a gauge theory（with torsion） of gravitation does include the coupling of spin with the gravitation field.The theory predicts that the motion for a spin particle or a rotating body would deviate from a geodesic one,and hence violate EP.In order to test this violation we suggest experiments in both a laboratory on the Earth and a satellite in space.