High-precision test of isotropy of light propagation using actively rotated optical resonators

局部洛伦兹不变性（LLI）是自然界的一种基本对称性，迄今为止已被实验证明在很大程度上是有效的。然而，不知道LLI是严格有效还是仅近似有效。如果发现存在违反LLI的情况，其详细特征可以为所有力的基本理论提供输入。从理论的角度来看，LLI的违反是可能的，并提出了描述它的模型。由于这个原因，全世界都在努力对粒子和光子进行更精确的实验测试。最近，我们对光子进行了最精确（10倍）的LLI测试（Antonini et al., 2005），达到（c/c < 6¿10-16）的水平。重要的是进一步提高这一水平几个数量级，因为根据理论论证，LLI违反的可能水平由基本比Mw/Mplanck（1¿10-I7）给出，其中Mw是电弱相互作用的规范玻色子的质量。我们提出的实验提供了在这个水平上对光子的洛伦兹违反（以及由于电子的非自旋贡献）的第一个和一个强有力的测试。在提议的3年项目中，我们期望：将光速可能的各向异性的极限提高1000倍，达到（c/c < 6¿10-19）的水平；测量标准模型扩展理论的8个系数，精度比目前最好的结果高100到1000倍，达到2¿10-18的水平。这个实验将是世界上第一个在这个水平上探索LLI光子的实验。我们将开发的技术也将为开发适用于下一代光学原子钟的超稳定激光器做出重大贡献。

Local Lorentz Invariance (LLI) is a fundamental symmetry of nature that has until now experimentally been proven to be valid to a high degree. However, it is not known if LLI is strictly or only approximately valid. If a violation of LLI is found to exist, its detailed characterization could provide input for a fundamental theory of all forces. From the theoretical point of view, a violation of LLI is regarded as possible and models describing it have been proposed. For this reason there are worldwide efforts to perform more accurate experimental tests both on particles and on photons. Recently, we have performed the most precise (by a factor of 10) test of LLI for photons (Antonini et al., 2005), reaching the level (c/c < 6 ¿ 10-16.It is important to further improve this level by a few orders, since according to theoretical arguments, a possible level of LLI violation is given by the fundamental ratio Mw/Mplanck ( 1 ¿ 10-I7, where MW is the mass of the gauge bosons of the electroweak interaction. Our proposed experiment provides both the first and a strong test of Lorentz violation for photons (and non-spin contribution due to electrons) at this level.Within the proposed 3-year project we expect to:¿ improve the limits for a possible anisotropy of the velocity of light by a factor of 1000 to the level (c/c < 6 ¿ 10-19¿ measure 8 coefficients of the Standard Model extension theory with an accuracy between 100 and 1000 times higher than the currently best results, reaching a level of up to 2 ¿ 10-18.The experiment will be the first worldwide to explore LLI for photons at this level.The techniques we will develop will also make a significant contribution toward the development of ultrastable lasers suitable for next-generation optical atomic clocks.