Determination of the Newtonian Gravitational Constant<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>G</mml:mi></mml:math>with Time-of-Swing Method

Luo, Jun; Liu, Qi; Tu, Lai; Shao, Cheng-Gang; Liu, Linxia; Yang, Shan-Qing; Li, Qing; Zhang, Yating

doi:10.1103/physrevlett.102.240801

Cited by 101 publications

(55 citation statements)

References 23 publications

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“…For example, in the measurement of the Newtonian gravitational constant G with the time-of-swing method, one needs to estimate the period of the torsion balance with high precision [1,2,3,4]. However, the experimental data is inevitably polluted by a variety of noises, and thus the precision of period estimation may be also limited by these noises.…”

Section: Introductionmentioning

confidence: 99%

Study on the Equivalence Between Nonlinear Least Squares Method and Correlation Method in Period Extraction of Torsion Pendulum

Zhan¹,

Wu²

2016

Proceedings of the 2nd Information Technology and Mechatronics Engineering Conference (ITOEC 2016TOEC 2016)

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Abstract. In the measurement of G using time-of-swing method, the accurate determination of G depends on the period extraction of torsion balance with high precision. There are a great many methods of extracting period, and the nonlinear least squares fitting method and the correlation method are most frequently applied to extract the torsion balance period accurately. Though some papers have claimed the two methods are equivalent, lacking in complete theoretical derivation. In this paper, the influence of Gaussian white noise on the period extraction accuracy by the two methods is theoretically derived detailedly and simulated in MATLAB. Both results show that although there exists some differences between two methods in process of data analysis, the accuracy of period extraction is still the same.

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Section: Introductionmentioning

confidence: 99%

Study on the Equivalence Between Nonlinear Least Squares Method and Correlation Method in Period Extraction of Torsion Pendulum

Zhan¹,

Wu²

2016

Proceedings of the 2nd Information Technology and Mechatronics Engineering Conference (ITOEC 2016TOEC 2016)

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“…Considering a linear density distribution along the axial direction, the eccentricities of the two cylinders are determined to be 10.3(2.6) and 6.3(3.7) µm, respectively, which contribute a correction of 210(78) ppm to the value of G. The other is from the air buoyancy when the source masses are moved out from the far position, which contributes a correction of 150 ppm. These two effects lead the HUST-99 G value to be 360 ppm larger, and the corrected G value is show the entire experimental apparatus and the pendulum and source masses in the vacuum chamber, respectively (in [8,16] is used as the torsion pendulum and hangs from a passive magnetic damper by using a 25 µm diameter, 890 mm long annealed tungsten fibre. The damper is suspended by a 50 µm diameter, 90 mm long pre-hanger tungsten fibre and used to reduce any tilt-twist coupling to the torsion fibre [32][33][34].…”

Section: Determination Of G At Hust (A) Hust-99 G Measurement and Itsmentioning

confidence: 99%

“…Up to now, there have been seven G values with claimed uncertainties of less than 50 ppm (parts per million) published by different groups [4][5][6][7][8][9][10], as shown in figure 1. Gundlach & Merkowitz [4] presented the most precise G value with u r = 14 ppm (UWash-00) by using the angular acceleration feedback method, which is slightly larger than G 2010 (CODATA-2010 recommended G value, hereinafter the same).…”

Section: Introduction (A) Backgroundmentioning

confidence: 99%

“…The revised G value was named as HUST-05 in the 2006 CODATA adjustment [15]. In 2009, we obtained a latest G value by using a rectangular glass block pendulum and two spherical source masses with the same method [8,16]. This result was adopted by 2010 CODATA adjustment and named HUST-09.…”

Section: Introduction (A) Backgroundmentioning

confidence: 99%

“…This paper presents the key features in HUST-99 (HUST-05), HUST-09 and the ongoing G measurements. For detailed descriptions of each experiment see earlier studies [8,11,14,16].…”

Section: Introduction (A) Backgroundmentioning

confidence: 99%

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G measurements with time-of-swing method at HUST

Liu

Zhao

et al. 2014

Phil. Trans. R. Soc. A.

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We review the G measurements with time-of-swing method at HUST. Two independent experiments have been completed and an improved experiment is in progress. The first G value was determined as 6.6699(7)×10 −11 m 3 kg −1 s −2 with a relative standard uncertainty ( u r ) of 105 ppm by using a long period torsion pendulum and two cylindrical source masses. Later, this result was corrected to be 6.6723(9)×10 −11 m 3 kg −1 s −2 with u r =130 ppm after considering the density distribution of the cylinders and the air buoyancy, which was 360 ppm larger than the previous value. In 2009, a new experiment by using a simple block pendulum and spherical source masses with more homogeneous density was carried out. A series of improvements were performed, and the G value was determined to be 6.67349(18)×10 −11 m 3 kg −1 s −2 with u r =26 ppm. To reduce the anelasticity of the torsion fibre, fused silica fibres with Q 's of approximately 5×10 4 are used to measure G in the ongoing experiment. These fibres are coated with thin layers of germanium and bismuth in turn to reduce the electrostatic effect. Some other improvements include the gravity compensation, reduction of the coating layer effect, etc. The prospective uncertainty of the next G value is 20 ppm or lower.

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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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Determination of the Newtonian Gravitational ConstantGwith Time-of-Swing Method

Cited by 101 publications

References 23 publications

Study on the Equivalence Between Nonlinear Least Squares Method and Correlation Method in Period Extraction of Torsion Pendulum

Study on the Equivalence Between Nonlinear Least Squares Method and Correlation Method in Period Extraction of Torsion Pendulum

G measurements with time-of-swing method at HUST

Progress in Precise Measurements of the Gravitational Constant

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