Precision Measurements with Nuclear Spins

点击翻译按钮获取中文摘要

In this project, large collections of atoms will be manipulated with laser light in order to align their magnetic fields. This will allow high precision measurements of the atomic precession frequencies to address several practical and fundamental physics questions. One question is whether the Universe is filled with invisible particles, called dark matter, which only interact very weakly with ordinary atoms. If such particles exist, they can modify the atomic precession frequencies. New measurement techniques will be developed to increase the sensitivity of the experiment to such interactions. Another question is whether atoms placed in empty space have a certain preferred orientation direction. Sensitive measurements of the atomic precession frequencies can also be used to detect very weak magnetic fields and can be used for spatial orientation. The question of fundamental sensitivity limits in these practical applications will be explored during the project.Large ensembles of polarized nuclear spins with long spin coherence times will be used for several precision measurements. A continuous-flow liquid Xe-129 magnetometer will be developed to search for possible resonant interactions with dark matter particles. A He-3-Ne-21 co-magnetometer will be developed to search for very light dark matter particles and for tests of local Lorentz invariance. A Rb-Ne co-magnetometer with high bandwidth and improved long-term stability will be developed to search for new long-range spin dependent forces. In each system the interactions between dense spin-polarized ensembles will be studied in detail in order to approach the fundamental quantum limits of spin co-magnetometers and to allow further advances in practical applications of precision spin sensing.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.