Measurement of the Gravitostatic Aharonov-Bohn Effect

在基本力中，引力可能是日常生活中最熟悉的一种，但它的物理学却最不为人所知。首先，它不符合基于量子力学的粒子物理学的标准模型。此外，量子力学中的引力作用在实验测量中相对难以捉摸。因此，物理学中最重要的挑战之一就是找到研究引力如何影响量子系统的新方法。该小组将演示所谓的引力Aharonov-Bohm效应（AB效应）。在经典物理学中，两个物体之间的相互作用可以等效地用力或势能来描述。然而，Aharonov和Bohm指出，在量子力学中，即使两个物体之间没有力，它们也可以相互影响。这已经在电磁力和电势的实验中得到了验证。该小组将建造一个专门的仪器来研究重力是否存在类似的阿哈罗诺夫-玻姆效应。这将证明，即使在引力没有引起任何经典力的情况下，它也会影响量子系统；关于经典引力作用于粒子局部的知识不足以预测粒子的量子力学行为；用费曼的话说，很长一段时间以来，人们都认为势不是“真实的”，因为在描述任何当时已知的可观测现象时，势都可以用力场来代替。然而，AB效应证明了势是真实存在的，力正在从物理定律的现代表达中慢慢消失。该小组正在与工业伙伴合作，将这项工作中开发的技术应用于生产先进的惯性传感器，以改善导航和定位。该实验将以激光冷却铯原子为基础，这些原子被放置在一个光学晶格中，在两个球形质量的特殊排列中，产生“W”形的引力势。原子将处于重力势的极值，因此在球形质量和原子之间将没有合力。然而，质量应该引起原子物质波的相对相移。该小组将通过实验证明AB效应的显著特征，如非局域性和非色散性。光学晶格将成为法布里-珀罗腔内的驻波，以控制光学波阵面并提供激光强度增强。

Of the fundamental forces, gravity is probably the one most familiar in everyday life, yet its physics is the least well understood. For one, it does not fit into the standard model of particle physics, which is based on quantum mechanics. In addition, the action of gravity in quantum mechanics has been relatively elusive to experimental measurement. One of the most important challenges in physics is thus to find new ways to investigate how gravity affects quantum systems. The group will give a demonstration of the so-called Aharonov-Bohm effect (AB effect) for gravity. In classical physics, the interaction between two objects can be described equivalently based on forces or on potential energies. Aharonov and Bohm, however, pointed out that in quantum mechanics, two objects can influence each other even if there are zero forces between them. This has been verified experimentally for electromagnetic forces and potentials. The group will construct a specialized apparatus to investigate whether there is an analogous Aharonov-Bohm effect for gravity. This will demonstrate that gravity affects a quantum system even when it does not cause any classical force; that knowledge of the classical gravitational force acting locally on a particle is not sufficient to predict the particle's quantum-mechanical behavior; and help develop a new way of measuring Newton's gravitational constant G. Paraphrasing R. P. Feynman, for a long time it was believed that potentials were not "real", since they could be replaced by force fields in the description of any observable phenomenon then known. However, the AB effect has established that potentials are real, and forces are slowly disappearing from the modern expression of physical law. The group is collaborating with industrial partners to apply the techniques developed in this work in the production of advanced inertial sensors for improved navigation and positioning.The experiment will be based on laser-cooled cesium atoms held in an optical lattice, inside a special arrangement of two spherical masses that produce a "W"-shaped gravitational potential. The atoms will be at extrema of the gravitational potential, so that there will be no net force between the spherical masses and the atoms. Nevertheless, the masses should cause a relative phase shift of the atomic matter waves. The group will experimentally demonstrate the distinguishing features of the AB effect, such as nonlocality and nondispersiveness. The optical lattice will be a standing wave inside a Fabry-Perot cavity, to control the optical wave-fronts and provide laser intensity enhancement.