New Torsion Balance Technique to Test Gravity at Short Distances

短距离测试重力的新扭转平衡技术

• 批准号: 0700912
• 负责人: Jens Gundlach
• 金额: --
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-11-15 至 2008-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0700912&HistoricalAwards=false
• 关键词: New; Torsion; Balance; Technique; Test

This award supports preliminary research on a new method to test Newton's law of gravity at length scales shorter than 100 micrometers. Recent theoretical suggestions including unification scenarios, extra dimensions, and cosmological considerations involving dark energy all involve the possibility of a breakdown of Newtonian gravity for short ranges. Previously published results by the PI and others described upper limits to such a breakdown at around 100 micrometers using a torsion pendulum with an array of holes. The new method uses a different true null-experiment with a simple, yet highly efficient geometry designed to detect violations of Newtonian gravity at much shorter distances. A vertical plate torsion pendulum will hang parallel to an attractor plate which generates a uniform gravitational field. As this plate is moved toward and away from the pendulum, the forces on the pendulum will not change if Newtonian gravity holds. To maximize the pendulum's sensitivity to violations of Newtonian gravity, it is made from a plate with a step in its density profile, so that one half of the plate's mass is closer to the attractor than the other. To avoid forces due to electrostatics and residual gas, a thin metallic membrane is placed in the space between the attractor and the pendulum. This experiment is an alternative approach to test using existing torsion balances, with entirely different systematic uncertainties and the potential to test gravity at length scales as small as 20 micrometers. This award will support graduate students to build a scientific instrument and conduct a very challenging measurement, providing excellent training in all the aspects of experimental physics and scientific research. The new method involves many technical innovations that may find applications in other areas such as gravity-wave detection.

该奖项支持在小于 100 微米的长度尺度上测试牛顿万有引力定律的新方法的初步研究。最近的理论建议，包括统一情景、额外维度和涉及暗能量的宇宙学考虑，都涉及牛顿引力在短距离内崩溃的可能性。 PI 和其他人之前发表的结果描述了使用带有一系列孔的扭摆在 100 微米左右的击穿上限。新方法使用了不同的真实零实验和简单而高效的几何结构，旨在在更短的距离内检测违反牛顿引力的情况。垂直板扭摆将平行于吸引板悬挂，从而产生均匀的引力场。当该板朝向和远离摆锤移动时，如果牛顿引力成立，摆锤上的力将不会改变。为了最大限度地提高摆锤对违反牛顿引力的敏感度，它由一块密度分布有台阶的板制成，这样板的一半质量比另一块更靠近吸引子。为了避免静电和残余气体产生的力，在吸引器和摆锤之间的空间中放置了一层薄金属膜。该实验是使用现有扭力天平进行测试的另一种方法，具有完全不同的系统不确定性，并且有可能在小至 20 微米的长度尺度上测试重力。该奖项将支持研究生建造科学仪器并进行极具挑战性的测量，为实验物理和科学研究的各个方面提供出色的培训。新方法涉及许多技术创新，可能会在重力波探测等其他领域得到应用。