Feedback control of torsion balance in measurement of gravitational constant <i>G</i> with angular acceleration method

Quan, Lidi; Chen, Xue; Shao, Cheng-Gang; Yang, Shan-Qing; Tu, Liangcheng; Wang, Yongji; Luo, Jun

doi:10.1063/1.4861189

Cited by 16 publications

(14 citation statements)

References 16 publications

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“…In Ref. [13], the distance between the center of the test mass and the source masses is ∼ 17 cm [44]. However, in the case of gravitational wave detectors and optically-levitated microspheres, the typical smallest distances in the analysis above are 5 m and 30 cm, respectively.…”

Section: Discussion On Accuracymentioning

confidence: 99%

Measurement of the Newtonian constant of gravitation G by precision displacement sensors

Kawasaki

2020

Class. Quantum Grav.

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The Newtonian constant of gravitation G historically has the largest relative uncertainty over all other fundamental constants with some discrepancies in values between different measurements. We propose a new scheme to measure G by detecting the position of a test mass in a precision displacement sensor induced by a force modulation from periodically rotating source masses. To seek different kinds of experimental setups, laser interferometers for the gravitational wave detection and optically-levitated microspheres are analyzed. The high sensitivity of the gravitational wave detectors to the displacement is advantageous to have a high signal-to-noise ratio of 10 −6 with a few hours of the measurement time, whereas the tunability of parameters in optically-levitated microspheres can enable competitive measurements with a smaller scale setup dedicated to the G measurement. To achieve an accuracy of G better than currently available measurements, developments in force calibration is essential. These measurements can provide an alternative method to measure G precisely, potentially leading to the improvement in the accuracy of G, as well as a better search for non-Newtonian gravity at a length scale of ∼ 1 m.

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Section: Discussion On Accuracymentioning

confidence: 99%

Measurement of the Newtonian constant of gravitation G by precision displacement sensors

Kawasaki

2020

Class. Quantum Grav.

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“…Here, we would like to make an analysis on the systematic error of torsion experiment. As shown in Figure 6, when the big ball attracts the small ball on its own side, it should attract the other small one on the opposite side (Xue et al, 2014) (Rosi et al, 2014) (Newman et al, 2014) (Fan et al, 2008) (Quan et al, 2014). This can lead to the notable systematic error.…”

Section: Figure 4: the Fitting Equations And Fitting Linesmentioning

confidence: 98%

Two Values Of The Constant G Obtained From Inclining-Pull Projection Method

Qing-Gui¹

2019

Indian Journal of Scientific Research

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The Newtonian gravitational constant is regarded as the most fundamental constant. So far, more than 200 experiments have been done to measure its true value. But large discrepancies in those results appeared. Owing to the weakness of the gravitational interaction and the impossibility of shielding its effects, it is very difficult to find new method to measure G. Thus, most previous experiments were based on the torsion pendulum or torsion balance. Here we report the inclining-pull projection method to measure the gravitational constant G. The experimental idea is completely different from previous. With different center distances of two balls, we do this experiment two times and gain two values: G = 6.858448 X 10-11 m 3 kg-1 S-2 , with an uncertainty of about 2.5%; G = 6.785245 X 10-11 m 3 kg-1 S-2 , with the uncertainty of about 2.3%. It implies it is possible for G not to be a constant.

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“…Our group conducted the proof‐of‐principle experiment with the angular acceleration feedback method from 2008 to 2012, and the main goal of this experiment is testing all aspects of the experimental design, especially the stability and the feedback function . Then the apparatus was redesigned and completely rebuilt, and the schematic diagram of the apparatus is shown in Figure .…”

Section: Latest Measurement Of Gmentioning

confidence: 99%

Progress in Precise Measurements of the Gravitational Constant

Liu

et al. 2019

Annalen der Physik

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The Newtonian gravitational constant G, which is one of the earliest fundamental constants introduced by human beings, plays an important role in cosmology, astrophysics, geophysics, metrology, and so on. In spite of the measurement of G having a relative longer history and more than 200 measurement results having been obtained during the past 200 years, G still remains the least precisely known among all fundamental physical constants up to now. Over the past three decades, many experimental physicists devoted themselves to the G measurement with various methods and resulted in a dozen precise values of G. However, the determined results are still in poor agreement with each other. A brief overview of the significance of the gravitational constant G is given herein, followed by an introduction into the history of G measurement. A summary of the five latest precise measurements performed during the past few years is presented. Finally, an outlook of the future development of G measurement is provided.

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Feedback control of torsion balance in measurement of gravitational constant G with angular acceleration method

Cited by 16 publications

References 16 publications

Measurement of the Newtonian constant of gravitation G by precision displacement sensors

Measurement of the Newtonian constant of gravitation G by precision displacement sensors

Two Values Of The Constant G Obtained From Inclining-Pull Projection Method

Progress in Precise Measurements of the Gravitational Constant

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