Tests of Fundamental Symmetries Using Spin Magnetometers

该项目包括两个实验，旨在使用自旋磁力计测试自然界的基本对称性。第一个实验将通过使用液体129-Xe寻找永久电偶极矩(EDM)，为违反时间反转对称性设定新的限制。它将限制由超对称性和标准模型的其他扩展引起的T和CP破坏的新来源。目前抗磁原子电火花加工的最佳极限来自199-Hg实验，并受到统计噪声的限制。与最新版本的199-Hg实验相比，使用液体Xe，我们将能够将原子数量增加8个数量级，将电场强度增加10倍。SQUID磁强计将用于检测自旋进动和监测泄漏电流。实验二将通过比较同一晶胞中3-He和39-K原子的自旋进动频率，对CPT破坏和Lorentz对称性破坏设定新的极限。弦理论和其他量子引力理论中可能会出现CPT和Lorentz对称性破坏。K磁强计将在低磁场和高数密度下工作，消除了自旋交换引起的弛豫。我们将使用一种新的自补偿设计，它利用K和3-He原子之间的自旋交换耦合，同时自动消除磁场波动，并消除许多通常限制原子自旋磁强计的系统影响。我们预计将把现有的限制提高2-3个数量级。

This project consists of two experiments aimed at testing fundamental symmetries of nature using spin magnetometers. The first experiment will set new limits on violation of time-reversal symmetry by searching for a permanent Electric Dipole Moment (EDM) using liquid 129-Xe. It will constrain new sources of T and CP violation caused by Supersymmetry and other extensions of the Standard Model. The current best limit on EDM of a diamagnetic atom comes from the 199-Hg experiment and is limited by statistical noise. Using liquid Xe we will be able to increase the number of atoms by eight orders of magnitude and the electric field strength by a factor of 10 relative to the latest version of the 199-Hg experiment. SQUID magnetometers will be used for detection of spin precession and for monitoring leakage currents. The limits on CP violation can be improved by 2 to 4 orders of magnitude.The second experiment will set new limits on CPT violation and Lorentz symmetry violation by comparing the spin precession frequencies of 3-He and 39-K atoms contained in the same cell. CPT and Lorentz symmetry violations can occur in string theories and other theories of quantum gravity. The K magnetometer will operate at low magnetic field and high number density, eliminating relaxation due to spin exchange. We will use a new self-compensating design that takes advantage of the spin-exchange coupling between K and 3-He atoms, while automatically canceling magnetic field fluctuations and eliminating many systematic effects typically limiting atomic spin magnetometers. We expect to improve the existing limits by 2-3 orders of magnitude.