标题： 关于用卫星梯度测量约束引力的宇称破坏 显示英文标题

标题： Towards Constraining Parity-Violations in Gravity with Satellite Gradiometry

摘要： 引力中的宇称破缺（如果存在）可能会产生重要的影响，寻找和检验可能的观测效应具有重要意义。Chern-Simons修正引力是一种自然的引力宇称破缺模型。特别是，考虑到扩展到爱因斯坦-希尔伯特作用量的二阶曲率项时，已知引力宇称破缺理论将归结为动力学Chern-Simons引力。在这封信中，我们概述了利用轨道重力梯度仪测试动力学Chern-Simons引力的理论原理，这些梯度仪可以自然地融入未来的卫星重力任务中。由于Mashhoon-Theiss（异常）效应，在动力学Chern-Simons引力中计算出的长期重力梯度信号，可以改善由这种测量方案得到的相应Chern-Simons长度尺度$\xi^{\frac{1}{4}}_{cs}$的约束。对于轨道超导梯度仪或光学读数的梯度仪，原则上可以获得一个界限$\xi^{\frac{1}{4}}_{cs}\leq 10^6 \ km$（甚至更好），这至少比基于GP-B任务和LAGEOS I、II卫星观测结果的当前界限强两个数量级。 显示英文摘要

摘要： Parity violation in gravity, if existed, could have important implications, and it is meaningful to search and test the possible observational effects. Chern-Simons modified gravity serves as a natural model for gravitational parity-violations. Especially, considering extensions to Einstein-Hilbert action up to second order curvature terms, it is known that theories of gravitational parity-violation will reduce to the dynamical Chern-Simons gravity. In this letter, we outline the theoretical principles of testing the dynamical Chern-Simons gravity with orbiting gravity gradiometers, which could be naturally incorporated into future satellite gravity missions. The secular gravity gradient signals, due to the Mashhoon-Theiss (anomaly) effect, in dynamical Chern-Simons gravity are worked out, which can improve the constraint of the corresponding Chern-Simons length scale $\xi^{\frac{1}{4}}_{cs}$ obtained from such measurement scheme. For orbiting superconducting gradiometers or gradiometers with optical readout, a bound $\xi^{\frac{1}{4}}_{cs}\leq 10^6 \ km$ (or even better) could in principle be obtained, which will be at least 2 orders of magnitude stronger than the current one based on the observations from the GP-B mission and the LAGEOS I, II satellites.