Search for Gravitational Strength Forces Below 1 cm

将进行实验，以检验牛顿引力定律在质量间分离小于1厘米时的情况。对于一厘米到十分之一毫米之间的距离，实验将足够灵敏，可以探测重力，并测试是否偏离牛顿平方反比定律。对于较小的分离，实验可以探测到所提出的新的短程力比引力强，但仍然比其他已知力弱许多个数量级。研究人员将首先用现有的室温仪器完成正在进行的实验，然后建造一种灵敏度更高的新低温仪器。灵敏测力器采用平面钨-张力振荡器。目前，理论物理学家对在一厘米以下的长度尺度上可能存在新的弱力的可能性非常感兴趣。弦理论试图涵盖所有已知的物理学，包括引力，它通常预测光场的模数。当它们通过某些机制获得质量时，它们可能会调节一毫米范围内的力。探测这种力将为严格理论提供戏剧性的证据。理论家还提出，在通常的三维空间之外，可能存在几个新的紧凑空间维度，引力之所以弱，是因为它能够在额外的维度中展开。当额外维度数为2时，这一观点会导致在约1毫米处偏离牛顿引力定律。预测偏差的实验证据将是我们理解基础物理的戏剧性的一步。

Experiments will be conducted to test Newtons law of gravitation atinter-mass separations of less than one centimeter. For separationsbetween one centimeter and one tenth of a millimeter, the experimentswill be sensitive enough to detect gravity and to test for deviationsfrom Newtons inverse-square law. For smaller separations theexperiments could detect proposed new short-range forces stronger thangravity but still many orders of magnitude weaker than other knownforces. The investigators will first complete on-going experiments withan existing room temperature apparatus, and then construct a newcryogenic instrument with greater sensitivity. A planar tungstentorsional oscillator is used as the sensitive force detector. There iscurrently intense interest among theoretical physicists in thepossibility that there may exist new feeble forces at length scalesbelow one centimeter. String theory, which seeks to encompass allknown physics including gravitation, generally predicts light fieldscalled moduli. When these acquire mass through certain mechanisms,they may mediate forces with a range of about one millimeter.Detecting such forces would provide dramatic evidence for stringtheory.Theorists have also proposed that there may exist several new compactspatial dimensions beyond the usual three, and that gravity is weakbecause it is able to spread out in the extra dimensions. When thenumber of extra dimensions is two, this view leads to large deviationsfrom Newtons law of gravitation at about one millimeter. Experimentalevidence of the predicted deviations would be a dramatic step forwardfor our understanding of fundamental physics.