Search for Gravity-Like Forces at Sub-100 microns Scale

寻找 100 微米以下尺度的类重力

• 批准号: 0554170
• 负责人: Aharon Kapitulnik
• 金额: $ 65.04万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0554170&HistoricalAwards=false
• 关键词: Search; Gravity; Like; Forces; Sub

This award supports an experimental program to probe deviations from Newtonian gravity at distances on the order of 25 microns as predicted by theories of physics beyond the Standard Model of fundamental particle interactions. A low temperature probe has been built to measure tiny forces expected at these distances. The force sensor is a micromachined silicon cantilever. A gold test mass is glued to the end of the cantilever. An alternating pattern of gold and silicon bars is oscillated below the test mass; the coupling between the test mass and the varying gravitational field of the moving drive mass excites the cantilever on resonance. A fiber interferometer measures the cantilever motion and from this measurement, the force between the masses is deduced. Due to the geometry of the drive mass, as the longitudinal equilibrium position of the drive mass is varied, any gravitational force will show a distinct periodicity. Comparison of the measured force to predictions from finite element analysis yields bounds on new gravity-like forces which could signal new physics.While the Standard Model successfully unifies the electromagnetic, the strong and the weak interactions, it ignores gravity. This poses a great mystery in fundamental physics: why is even this most feeble subatomic force, i.e. the weak force, so much stronger than gravity? Modern theories that attempt to answer this question predict modifications to Newton's law at much longer length scales, up to 1 millimeter. The technology used in this experiment is at the cutting edge of micro-fabricated devices.

该奖项支持一个实验计划，以探测牛顿重力以25微米的距离探测牛顿重力的偏差，这是物理学理论以外的基本粒子相互作用的标准模型所预测的。 已经建立了低温探针，以测量在这些距离处预期的微小力。力传感器是微机械硅悬臂。黄金测试块被粘在悬臂的尽头。在测试质量下方，将黄金和硅条的交替模式振荡。测试质量与移动驱动质量的不同重力场之间的耦合激发了悬臂共振。纤维干涉仪可以测量悬臂运动，并从这种测量中，推导质量之间的力。由于驱动质量的几何形状，随着驱动质量的纵向平衡位置的变化，任何重力都会显示出明显的周期性。比较测得的力与有限元分析的预测的比较在新的重力样力上产生了界限，这可能会向新的物理发出信号。虽然标准模型成功地统一了电磁，强和弱相互作用，但它忽略了重力。这在基本物理学上构成了一个巨大的谜：为什么即使是这种最微弱的亚原子力，即弱力，比重力强得多？试图回答这个问题的现代理论预测了牛顿定律的修改，长度较长，最高为1毫米。 该实验中使用的技术位于微型制造设备的最前沿。