Measurements of the gravitational constant using two independent methods

Li, Qing; Xue, Changxi; Liu, Jianping; Wu, Jing; Yang, Shan-Qing; Shao, Cheng-Gang; Quan, Lidi; Tan, Wen-Hai; Tu, Lai; Liu, Qi; Xu, Heming; Liu, Linxia; Wang, Qinglan; Hu, Zhong-Kun; Zhou, Zebing; Luo, Pengshun; Wu, Shiyou; Milyukov, V. K.; Luo, Jun

doi:10.1038/s41586-018-0431-5

Cited by 135 publications

(123 citation statements)

References 45 publications

Supporting

Mentioning

112

Contrasting

Unclassified

Order By: Relevance

“…The recently published results of the new measurements [4] show that, despite two independent methods of measuring the gravitational constant (using torsion pendulum experiments with the time-of-swing method and the angular-acceleration-feedback method), the results differ in the fourth order after the decimal point. The G values of 6.674184 × 10 −11 and 6.674484 × 10 −11 were obtained with a relative standard uncertainties of 11.64 ppm and 11.61 ppm, respectively.…”

Section: Introductionmentioning

confidence: 99%

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

Zaripov¹

2019

Symmetry

View full text Add to dashboard Cite

This work is the extension of author's research, where the modified theory of induced gravity (MTIG) is proposed. The theory describes two systems (stages): Einstein (ES) and "restructuring" (RS). We consider equations with quadratic potential that are symmetric with respect to scale transformations. The solutions of the equations obtained for the case of spaces defined by the Friedman-Robertson-Walker metric, as well as for a centrally symmetric space are investigated. In our model arise effective gravitational and cosmological "constants" , which are defined by the "mean square" of the scalar fields. In obtained solutions the values of such parameters as "Hubble parameter", gravitational and cosmological "constants" in the RS stage fluctuate near monotonically evolving mean values. These parameters are matched with observational data, described as phenomena of dark energy and dark matter. The MTIG equations for the case of a centrally symmetric gravitational field, in addition to the Schwarzschild-de Sitter solutions, contain solutions that lead to the new physical effects at large distances from the center. The Schwarzschild-Sitter solution becomes unstable and enters the oscillatory regime. For distances greater than a certain critical value, the following effects can appear: deviation from General relativity and Newton's law of gravitational interaction, antigravity. Telescope (HST) and Planck observatory [5]. The Hubble Space Telescope is tuned to measure the parallax Milky Way Cepheid variables and the distances are 1.7-3.6 kpc (the modern Universe). The measurements of the Planck spacecraft correspond to distant galaxies (the early Universe is about 375,000 years old). In 2018, the accuracy of the measurement of H 0 is increased to 2.3 percent, which gives H 0 = 73.48 ± 1.66 km · s −1 Mpc −1 . In the early Universe, based on the data received from the "Planck" spacecraft and ΛCDM theory, the predicted value is H 0 = 67.0 ± 1.2 km · s −1 Mpc −1 . The difference is about 9 percent. The accuracy of the measurements is about 4.5 percent. There is also a variance in the observations made at different times and different methods. For example, as indicated in the work [6], the local and direct definition of H 0 gives H 0 = 73.24 ± 1.74 km · s −1 Mpc −1 , and the most recent value from [7] in consent with ΛCDM is 66.93 ± 0.62 km · s −1 Mpc −1 . In our opinion, the problem can be reduced to a strong binding of calculations of the Hubble parameter H 0 to the ΛCDM model. In our work we present a model where, due to the oscillatory regime in the solutions of equations, the Hubble parameter also fluctuates with respect to the mean value-which is also a function of time.3. The problems of so-called "dark energy" (DE) and "dark matter" (DM). The first of them can be reduced to the problem of existence and smallness of the "cosmological constant" (par. 1). The challenge posed by the cosmological constant problem [1] has spurred many attempts at directly modifying Einstein's gravity at large distances [8]. As example of s...

show abstract

Section: Introductionmentioning

confidence: 99%

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

Zaripov¹

2019

Symmetry

View full text Add to dashboard Cite

show abstract

“…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: 98%

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

Kawasaki

2020

Class. Quantum Grav.

View full text Add to dashboard Cite

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.

show abstract

“…A similar methodology of MOND corrections needs to be applied for G values determined by the "angular acceleration feedback" (AAF) method, originally developed by Gundlach and Merkowitz [26] and later compared with the "time-of-swing" (ToS) method by Li et al [22]. Here the measured pendulum deflection during the cyclic motion of the source masses between "near" and "far" position (in this case a rotation of the source masses around the pendulum axis with constant angular velocity) is compensated by a feedback loop.…”

Section: Mond Corrections For Four Different Operational Modes Of Cavmentioning

confidence: 99%

“…Since the pendulum amplitude determines the MOND-related frequency increase 0 of the pendulum, the corresponding relative increase of  is given by The case of a mixed gravitational/electromagnetic restoring force is of particular interest for the socalled "time-of-swing" (ToS), which has gained popularity in recent years. As explained in detail in [22,31], this method relies on measurements of small changes of the resonance frequency of the pendulum for two different positions of the source masses: In the "near" position the additional gravitational force between the source masses and the pendulum body generates a small gravitational component of the restoring torque coefficient, which has to be added to the electromagnetic torque coefficient of a fibre-based torsion pendulum. It is of special interest to evaluate the MOND-induced restoring torque is a few percent of the total one only, which is the case for all ToS experiment listed in table 1.…”

Section: Figs 2c and Dmentioning

confidence: 99%

See 1 more Smart Citation

Evidence for modified Newtonian dynamics from Cavendish-type gravitational constant experiments

Klein

2020

Class. Quantum Grav.

View full text Add to dashboard Cite

Recent experimental results for the gravitational constant G from Cavendish-type experiments were analysed in the framework of Modified Newtonian Dynamics (MOND). MOND corrections were applied to the equation of motion of a pendulum, under the assumption that the magnitude of the horizontal time dependent gravitational acceleration determines the amount of MOND corrections. The large vertical component of the local gravitational field of the earth is fully compensated by the alignment of the torsion pendulum in accordance with Newton's third law and therefore not considered for MOND corrections. From the analysis of the MOND corrected equation of motion of a realistic torsion pendulum with mixed gravitational and electromagnetic restoring torque simple rules for meaningful MOND corrections of measured G values determined by different operational modes of Cavendish type G experiments were derived. Based on this analysis the reported discrepancies for G determined by "static deflection" and "electrostatic servo" methods of the "BIPM" experiment by Quinn et al. and between time-of-swing and angular acceleration feedback methods for the "HUST" experiment by Li et al. could be fully resolved by MOND corrections using one common MOND interpolation function, determined by a one parameter fit. The MOND corrected "BIPM" and "HUST" results, along with other "single method" results from G experiments by Gundlach and Merkovitz, Schlamminger et al. and Newman et al. lead to an average G value of 6.6742210 -11 m 3 kg -1 s -2 with a standard deviation of 12.5 ppm only. The applied MOND correction procedure and the fitted interpolation function employed for the G experiments were found to be consistent with the most viable MOND fits to galaxy rotation curves.

show abstract

Measurements of the gravitational constant using two independent methods

Cited by 135 publications

References 45 publications

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological ‘Coupling Constants’ in the Theory of Induced Gravity

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

Evidence for modified Newtonian dynamics from Cavendish-type gravitational constant experiments

Contact Info

Product

Resources

About