PM: Electron and Positron Magnetic Moments from a Quantum Cyclotron

在这个项目中，研究生将开发设备并部署具有非凡精度的量子方法。这种不同寻常的灵敏度应该可以探测到单个基本粒子的单量子跃迁。单个电荷的极微小运动将产生微小的电流，这些电流将被冷却到接近绝对零度的仪器检测到。一套新的量子方法将极大地抑制探测器中电子热运动产生的微弱噪声。悬浮在仪器上的粒子的量子态将由被捕获的电子或正电子在交替量子态之间跳跃的速率推断出来。新的仪器和量子方法将使测试我们对物理现实最基本的数学描述的最精确预测成为可能，即所谓的粒子物理标准模型（SM）。现代物理学的一大谜团是，这种SM描述在大多数情况下都非常有效，尽管它与我们宇宙的基本特征不一致。考虑到改变我们对物理现实的基本范式几乎肯定会导致新的科学技术，解决这个基本谜团将是极其重要的。此外，一个对国际科学和商业使用的单位制至关重要的基本常数将比以往任何时候都更精确地测量。新探测方法的核心是测量粒子振荡频率的“量子规避”方法。这些将与量子跃迁光谱一起使用，量子跃迁光谱采用量子非拆除检测占据的量子态。新方法将检测反作用力减小到最小内禀值到粒子振荡量子零点运动的反作用力。这个资助期的直接目标是确定电子和正电子的磁矩，达到前所未有的4 / 10^14的精度。这将是迄今为止对基本粒子进行的最精确的测量，它将使对SM的最精确预测达到这种不同寻常的精度成为可能，这种测试比目前可能的测试严格10倍。电子和正电子磁矩在这种非凡精度下的比较，将测试轻子CPT不变性，这是SM最基本的对称不变性，其严格程度可能高达200倍。这些测量也将为更精确地测量μ子磁矩铺平道路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, graduate students will develop apparatus and deploy quantum methods that are capable of extraordinary precision. The unusual sensitivity should allow detection of one-quantum transitions of a single elementary particle. Extremely small motions of a single charge will produce tiny electrical currents that will be detected using instruments cooled to temperatures near to absolute zero. The faint noise from the thermal motion of the electrons in the detector will be greatly suppressed with a new suite of quantum methods. The quantum state of the particle suspended on the apparatus will be deduced from the rate at which the trapped electron or positron jumps between alternate quantum states. The new apparatus and quantum methods will make it possible to test the most precise prediction of our most fundamental mathematical description of physical reality, the so-called Standard Model of Particle Physics (SM). A great mystery of modern physics is that this SM description works extremely well in most cases, even though it is not consistent with basic features of our universe. A resolution of this fundamental mystery would be extremely important, given that a change to our fundamental paradigm for physical reality would almost certainly lead to new science and technology. Furthermore, a fundamental constant that is essential to the system of units used internationally for science and commerce will be measured more accurately than ever before. At the heart of the new detection methods are “quantum circumvention” methods for measuring particle oscillation frequencies. These will be used with quantum jump spectroscopy that employs quantum nondemolition detection of occupied quantum states. The new methods will reduce the detection backaction to the minimal intrinsic value to that from the quantum zero-point motion of particle oscillations. The immediate goal for this grant period is to determine the electron and positron magnetic moments to an unprecedented accuracy of 4 parts in 10^14. This will be the most precise measurement ever made of an elementary particle, and it will make is possible to test the most precise prediction of the SM to this unusual precision, a test that is 10 times more stringent than is currently possible. The comparison of the electron and positron magnetic moments at this extraordinary precision will test lepton CPT invariance, the most fundamental symmetry invariance of the SM more stringently by a factor that could be as large as 200. The measurements will also prepare the way for more accurate measurements of the muon magnetic moment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.