LLI and Solid State electron edm searches

本实验研究计划的重点是继续测试局部洛伦兹不变性（LLI）和CPT（电荷共轭宇称时间）不变性的实验。LLI是相对论的基本假设之一，它认为物理定律在所有局部惯性系中都是一样的。众所周知，如果改变粒子的电荷、系统的宇称或时间的方向，实验可能会得到不同的结果，但如果这三者同时发生变化，那么CPT不变性预示着什么都不会改变。迄今为止，没有证据表明情况并非如此。为了得到结果，研究小组比较了汞和铯磁力计的相对进动频率，将其作为应用磁场相对于恒星方向的函数。这个实验的早期版本建立了几种可能违反这些对称性的最佳极限。在此期间，实验已经完全重建，该小组希望将实验精度提高100倍。在这一层次上，实验应对违反LLI和CPT的几种可能机制进行最严格的检验。该项目的更广泛影响涉及到一个特别强大的本科项目，该项目已经成功地培养了许多未来的科学家，并有望继续这样做。

This experimental research program focuses on the continuation of an experiment to test Local Lorentz Invariance (LLI) and CPT (charge conjugation parity time) invariance. LLI, one of the fundamental postulates of the theory of relativity, is the notion that the laws of physics are the same in all locally inertial frames. While it is known that an experiment may give a different result if one changes the charge on a particle or the parity of the system or the direction of time, if changes are made in all three at the same time, then CPT invariance predicts that nothing may change. To date there is no evidence to indicate that this is not the case.To get at the results the group compares the relative precession frequencies of mercury and cesium magnetometers as a function of the orientation of an applied magnetic field with respect to the fixed stars. An earlier version of this experiment established the best limits on several possible violations of these symmetries. In the interim the experiment has been completely rebuilt, and the group expects to achieve a factor of 100 improvement in the experimental precision. At this level the experiment should provide the most stringent test of several possible mechanisms for violating LLI and CPT. The broader impact of the project involves a particularly strong undergraduate program that has successfully trained a number of future scientists and may be expected to continue to do so.