Astroparticle-physics search for Lorentz violation in the photon sector

时空是动态的，量子力学本质上是随机的。这表明，在非常小的长度尺度下，空间可能不是完全光滑的，洛伦兹不变性可能从根本上被破坏。洛伦兹不变性的理想试验场是光子扇区。有19个无量纲参数，其中10个会导致真空双折射，并且已经被约束在10-32水平。当务之急是确定非双折射修正麦克斯韦理论剩余的9个参数。在这9个参数中，单一的各向同性参数是最难在实验室中确定或绑定的。申请者从超高能宇宙射线(Pierre Auger天文台)和TeV伽马射线(H.E.S.S.)获得了最佳间接边界。这个项目的目的是将这些界限提高至少两个数量级，这对各向同性参数尤其重要。在实验方面，这需要构建适当的俄歇数据样本。在理论方面，能量阈值条件必须加以改进，以纳入这样一个事实，例如，质子不是点粒子。此外，总有可能发现违反洛伦兹效应。出于这个原因，这个项目的很大一部分致力于搜索战略和对来自Auger的可用数据的初步扫描。探测光子区域中的洛伦兹破坏和提取非常严格的上界对整个物理学都是重要的，但当然是以不同的方式。

Spacetime is dynamic and quantum mechanics inherently random. This suggests that space may not be perfectly smooth at very small length scales and that Lorentz invariance may be fundamentally violated. An ideal testing ground of Lorentz invariance is the photon sector. There are 19 dimensionless parameters, of which 10 lead to vacuum birefringence and are already constrained at the 10-32 level. The most urgent task is to bound the remaining 9 parameters of the nonbirefringent modified Maxwell theory. Of these 9 parameters, the single isotropic parameter is the most difficult to bound or determine in the laboratory. The best indirect bounds were obtained by the applicants from ultra-high-energy cosmic rays (Pierre Auger Observatory) and TeV gamma-rays (H.E.S.S.). This project aims at improving these bounds by at least two orders of magnitude which is especially important for the isotropic parameter. On the experimental side, this requires the construction of an appropriate Auger data sample. On the theoretical side, the energy-threshold conditions must be refined to incorporate the fact that the proton, for example, is not a point particle. In addition, there is always the possibility of discovery of Lorentz-violating effects. For this reason, a significant part of this project is devoted to search strategies and a preliminary scan of the available data from Auger. Both the detection of Lorentz violation in the photon sector and the extraction of extremely tight upper bounds would be of importance to physics as a whole, but in a different way, of course.