通过下落原子对自由降落的普遍性进行高精度测试的基本限制
Fundamental limitations to high-precision tests of the universality of free fall by dropping atoms
摘要：
对自由降落和弱等效原理的普适性检验是对广义相对论基础的探索。违反的证据可能会导致发现一种新的力量。最好的扭秤实验已经排除了10^-13。冷原子跌落试验的结果已经达到了10^-7，而且无论是在地面上还是在太空中，都有望提高7 ~ 10个数量级。它们受到随机散粒噪声的限制，随机散粒噪声取决于云中原子的数量N。由于是在地球非均匀引力场中进行的质量下落实验，对初始条件比较敏感。由于云的初始条件误差引起的随机加速度被设计为与散粒噪声处于相同的水平，因此它们可以随着随其下降的数量而减小。在STE-QUEST太空任务计划中，目标是2 × 10 ^-15，它们必须比海森堡的原理极限高出8倍左右，减少这两个误差所需的积分时间为3年，任务持续时间为5年。相反，在不同的原子云之间的释放的偏移误差是系统性的，并引起一个系统性的效果，模仿违反。必须证明此类偏移在所有液滴中都与要求的一样小，设计时必须很小，并且必须进行测量。对于STE-QUEST来说，要达到它的目标，它们必须比每个单独的云的大小小几个数量级，而每个单独的云的大小又必须比不确定原理限制大8倍。即使所有的技术问题都解决了，释放出的云的系统误差可以忽略不计，仍然必须测量它们。然后，海森堡原理规定测量持续的时间与实验的时间一样长，并且效应的系统性需要多次测量才能排除它作为违反的来源。
英文摘要：
Tests of the universality of free fall and the weak equivalence principle probe the foundations of General Relativity. Evidence of a violation may lead to the discovery of a new force. The best torsion balance experiments have ruled it out to 10^-13. Cold-atom drop tests have reached 10^-7 and promise to do 7 to 10 orders of magnitude better, on the ground or in space. They are limited by the random shot noise, which depends on the number N of atoms in the clouds. As mass-dropping experiments in the non-uniform gravitational field of Earth, they are sensitive to the initial conditions. Random accelerations due to initial condition errors of the clouds are designed to be at the same level as shot noise, so that they can be reduced with the number of drops along with it. This sets the requirements for the initial position and velocity spreads of the clouds with given N. In the STE-QUEST space mission proposal aiming at 2x10^-15 they must be about a factor 8 above Heisenberg's principle limit, and the integration time required to reduce both errors is 3 years, with a mission duration of 5 years. Instead, offset errors at release between different atom clouds are systematic and give rise to a systematic effect which mimics a violation. Such offsets must be demonstrated to be as small as required in all drops, must be small by design and must be measured. For STE-QUEST to meet its goal they must be several orders of magnitude smaller than the size of each individual cloud, which in its turn must be at most 8 times larger than the uncertainty principle limit. Even if all technical problems are solved and the clouds are released with negligible systematic errors, still they must be measured. Then, Heisenberg's principle dictates that the measurement lasts as long as the experiment and the systematic nature of the effect requires many measurements for it to be ruled out as a source of violation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
