RUI: Search for Anomalous Spin Interactions with Atomic Comagnetometers

我们的研究计划包括两个不同的项目。 第一个项目是对原子自旋和地球质量之间的长程相互作用进行实验性研究。 这样的相互作用可能是由于迄今未发现的“第五种力”，或者如果引力，而不是广义相对论中假设的纯粹张量相互作用，具有标量/赝标量分量。 最近的理论工作表明，这种相互作用可能是宇宙加速膨胀的原因，通常归因于暗能量。我们的实验试图通过使用激光光谱同时测量铷的两种同位素的自旋进动来检测这种效应。我们的实验旨在将实验对长程自旋-质量相互作用的灵敏度提高1-3个数量级。 我们的第二个项目的重点是开发一个原型传感器的全球网络的光学磁强计为外来物理（GNOME），一个阵列的地理上分离，时间同步的超灵敏原子comagnetometers，将搜索相关的瞬态信号预示着新的物理。GNOME将对各种奇异粒子和场的核和电子自旋耦合敏感。到目前为止，还没有进行过这样的搜索，这使得GNOME成为新物理学的一个新的实验窗口。 一个可以用GNOME探测到的新物理学的具体而可行的例子，目前不受天体物理学观测和实验室实验的限制，是轻赝标量场的畴壁网络。我们目前对基础物理学的理解面临着许多深刻的谜团：宇宙的物质-反物质不对称性的起源，暗能量的性质，以及暗物质的性质。 我们的实验在地球上的实验室进行，使用原子自旋的精确测量来测试可能解释这些奥秘的几个假设。 有人提出，如果我们目前的引力理论是不完整的，引力的额外分量既可以产生推动宇宙分开的暗能量，也可以在大爆炸后产生过量的物质。 这些额外的引力分量也会导致原子自旋在地球引力场中进动，我们的实验将寻找这种效应。暗物质的一个可能的解释是一个不可见的银河系规模的“域墙”网络，它储存了相当大的质量和能量。 这些看不见的域墙会对原子自旋施加一个小扭矩，当地球穿过一堵墙时，可以检测到。 我们正在建立一个原型传感器敏感的域跨壁事件，这样的扭矩。 基于我们的原型的时间同步传感器阵列将搜索预示着这种新物理的天体物理起源的瞬态信号。我们的研究是在一所公立本科院校进行的，拥有多元化的学生群体，为许多本科生（包括大量女性和代表性不足的少数民族）提供最先进的实验物理学实践经验。

Our research program encompasses two different projects. The first project is an experimental search for a long-range interaction between atomic spins and the mass of the Earth. Such an interaction could arise due to a heretofore undiscovered "fifth force" or if gravity, as opposed to being a purely tensor interaction as assumed in general relativity, has a scalar/pseudoscalar component. Recent theoretical work has shown that such interactions could be the cause of the accelerating expansion of the universe, commonly attributed to dark energy. Our experiment seeks to detect this effect by simultaneously measuring the spin precession of two isotopes of rubidium using laser spectroscopy. Our experiment aims to improve experimental sensitivity to long-range spin-mass interactions by 1-3 orders of magnitude. Our second project focuses on development of a prototype sensor for the Global Network of Optical Magnetometers for Exotic physics (GNOME), an array of geographically separated, time-synchronized ultrasensitive atomic comagnetometers that will search for correlated transient signals heralding new physics. The GNOME would be sensitive to nuclear and electron spin couplings to various exotic particles and fields. To date, no such search has ever been carried out, making the GNOME a novel experimental window on new physics. A specific, feasible example of new physics detectable with the GNOME, presently unconstrained by astrophysical observations and laboratory experiments, is a network of domain walls of light pseudoscalar fields.Our present understanding of fundamental physics is confronted by a number of deep mysteries: the origin of the matter-antimatter asymmetry of the universe, the nature of dark energy, and the nature of dark matter. Our experiments, conducted in laboratories on Earth, use precise measurements of atomic spins to test several hypotheses that might explain these mysteries. It has been proposed that if our present theory of gravity is incomplete, additional components of gravity could both generate the dark energy pushing the universe apart and produce an excess of matter over antimatter after the Big Bang. These additional components of gravity would also cause atomic spins to precess in the Earth's gravitational field, the effect for which our experiment will search. A possible explanation of dark matter is a network of invisible galactic-scale "domain walls" that store considerable mass and energy. These invisible domain walls would exert a small torque on atomic spins that could be detected when the Earth passes through a wall. We are building a prototype sensor sensitive to such torques from domain wall-crossing events. An array of time-synchronized sensors based on our prototype will search for transient signals of astrophysical origin heralding such new physics. Our research is being carried out at a public undergraduate institution with a diverse student body, providing hands-on experience in state-of-the-art experimental physics to many undergraduate students (including a significant number of women and underrepresented minorities).