Figure - available from: Classical and Quantum Gravity
This content is subject to copyright. Terms and conditions apply.
Difference Δr between the numerically integrated time series of the distance with and without equation (3). The equations of motion were integrated with a numerical solver using explicit Runge–Kutta methods. We adopted a Sun-like star as primary and an Earth-sized planet as test particle. As far as the parameters ξ and Kα entering equation (3) are concerned, we adopted Kˆx=Kˆy=0>, while their magnitudes were chosen in order to have an initial ratio Anmc/ANewton ≈ 10⁻⁷ for equation (3) and the Newtonian acceleration; as far as their sign is concerned, the positive one was taken. As initial conditions of the test particle, common to both the numerical integrations, we adopted x0=a(1−e),y0=z0=0,x&a.dot;0=0,y&a.dot;0=GMa−1(1+e)(1−e)−1,z&a.dot;0=0>, with a = 1 au, e = I = 0. The time span is Δt = 100 yr. The resulting secular increase is in agreement with the theoretical prediction of equation (11) when calculated with the same physical and orbital parameters adopted in the numerical integration.
Source publication
We consider a non-rotating, massive test particle acted upon by a 'pressure'-type, non-geodesic acceleration arising from a certain general class of gravitational theories with nonminimal coupling between the matter and the metric. The resulting orbital perturbations for a two-body system are investigated both analytically and numerically. Remarkab...
Similar publications
A sinusoidally time-varying pattern of the values of the Newton's constant of
gravitation $G$ measured in Earth-based laboratories over the latest decades
has been recently reported in the literature. We put to the test the hypothesis
that the aforementioned harmonic variation may pertain $G$ itself in a direct
and independent way. We numerically i...
We present observations of three-dimensional magnetic power spectra in wavevector space to investigate the anisotropy and scalings of sub-Alfvénic solar wind turbulence at magnetohydrodynamic (MHD) scale using the Magnetospheric Multiscale spacecraft. The magnetic power distributions are organized in a new coordinate determined by wavevectors ( κ ˆ...
The transition between the supersonic solar wind and the subsonic heliosheath, the termination shock (TS), was observed by Voyager 2 (V2) on 2007 August 31-September 1 at a distance of 84 AU from the Sun. The data reveal multiple crossings of a complex, quasi-perpendicular supercritical shock. These experimental data are the starting point for a mo...
The role of large amplitude whistler waves in the energization and scattering of solar wind electrons has long been an interesting problem in Space Physics. To study this wave-particle interaction, we developed a vectorized test particle simulation with a variational calculation of the Lyapunov exponents. From using secular perturbation theory on t...
Retrieval of the properties of the middle and upper atmosphere can be performed using several different interferometric and photometric methods. The emission-shape and Doppler shift of both atomic and molecular emissions can be observed from the ground and space to provide temperature and bulk velocity. These instantaneous measurements can be combi...
Citations
... For these purposes, we will use the supplementary advances of the perihelia provided by INPOP10a (IMCCE, France) [34] and EPM2011 (IAA RAS, Russia) [35] ephemerides. These two ephemerides were recently adopted in planetary science [36,37] and in detecting gravitational effects and testing modified theories of gravity [28,[38][39][40][41][42][43][44][45][46][47]. In order to find a clearer bound, we will also take the Lense-Thirring effect due to the Sun's angular momentum into account. ...
As an extension of previous works on classical tests of Kaluza-Klein (KK)
gravity and as an attempt to find more stringent constraints on this theory,
its effects on physical experiments and astronomical observations conducted in
the Solar System are studied. We investigate the gravitational time delay at
inferior conjunction caused by KK gravity, and use new Solar System ephemerides
and the observation of \textit{Cassini} to strengthen constraints on KK gravity
by up to two orders of magnitude. These improved upper bounds mean that the
fifth-dimensional space in the soliton case is a very flat extra dimension in
the Solar System, even in the vicinity of the Sun.
... For these purposes, we will use the supplementary advances of the perihelia provided by the INPOP10a (IMCCE, France) [44] and EPM2011 (IAA RAS, Russia) [45] ephemerides. These two ephemerides were recently adopted in planetary science [46,47] and in detecting gravitational effects and testing modified theories of gravity [48][49][50][51][52][53][54][55][56][57]. Since INPOP10a and EPM2011 are significantly improved compared with their previous versions and the data sets they provide are much more accurate, we expect to obtain a tighter upper bound on αν. ...
The renormalization group running of the gravitational constant has a universal form and represents a possible extension of general relativity. These renormalization group effects on general relativity will cause the running of the gravitational constant, and there exists a scale of renormalization αν, which depends on the mass of an astronomical system and needs to be determined by observations. We test renormalization group effects on general relativity and obtain the upper bounds of αν in the low-mass scales: the Solar System and five systems of binary pulsars. Using the supplementary advances of the perihelia provided by INPOP10a (IMCCE, France) and EPM2011 (IAA RAS, Russia) ephemerides, we obtain new upper bounds on αν in the Solar System when the Lense-Thirring effect due to the Sun's angular momentum and the uncertainty of the Sun's quadrupole moment are properly taken into account. These two factors were absent in the previous work. We find that INPOP10a yields the upper bound as αν=(0.3±2.8)×10-20 while EPM2011 gives αν=(-2.5±8.3)×10-21. Both of them are tighter than the previous result by 4 orders of magnitude. Furthermore, based on the observational data sets of five systems of binary pulsars: PSR J0737-3039, PSR B1534+12, PSR J1756-2251, PSRB1913+16, and PSR B2127+11C, the upper bound is found as αν=(-2.6±5.1)×10-17. From the bounds of this work at a low-mass scale and the ones at the mass scale of galaxies, we might catch an updated glimpse of the mass dependence of αν, and it is found that our improvement of the upper bounds in the Solar System can significantly change the possible pattern of the relation between log|αν| and logm from a linear one to a power law, where m is the mass of an astronomical system. This suggests that |αν| needs to be suppressed more rapidly with the decrease of the mass of low-mass systems. It also predicts that |αν| might have an upper limit in high-mass astrophysical systems, which can be tested in the future.
... For other NMC gravity theories and their potential applications, see e.g. [22,23,24,25,26]. ...
In this work, the effects of a nonminimally coupled model of gravity on a
perturbed Minkowski metric are presented. The action functional of the model
involves two functions $f^1(R)$ and $f^2(R)$ of the Ricci scalar curvature $R$.
Based upon a Taylor expansion around $R = 0$ for both functions $f^1(R)$ and
$f^2(R)$, we find that the metric around a spherical object is a perturbation
of the weak-field Schwarzschild metric: the time perturbation is shown to be a
Newtonian plus Yukawa term, which can be constrained using the available
experimental results. We conclude that the Starobinsky model for inflation
complemented with a generalized preheating mechanism is not experimentally
constrained by observations. The geodetic precession effects of the model are
also shown to be of no relevance for the constraints.
By making use of the supplementary advances of the perihelia provided by INPOP10a and INPOP15a (France) and EPM2011 (Russia) ephemerides, we obtain improved Solar System bounds on the cosmologically viable \(f(\mathcal{G})\) gravity, where \(f\) is an arbitrary function of the Gauss–Bonnet invariant \(\mathcal{G}\). When we estimate new bounds on its model parameters, we consider the Lense–Thirring effect caused by the Sun’s angular momentum and the uncertainty of the Sun’s quadrupole moment, neither of which were included in related works before. The bounds we obtain in the present work are tighter than the previous ones by at least 5 orders of magnitude.
By using purely geometric forces on a noncommutative spacetime, noncommutative spectral geometry (NCSG) was proposed as a possible way to unify gravitation with the other known fundamental forces. The correction of the NCSG solution to Einstein's general relativity (GR) in the four-dimensional spacetime can be characterized by a parameter \(\beta\sim 1/\sqrt{f_{0}}\), where \( f_{0}\) denotes the coupling constants at the unification. The parameter \( \beta\) contributes a Yukawa-type correction \(\mathrm{exp}(-\beta r)/r\) to the Newtonian gravitational potential at the leading order, which can be interpreted as either the massive component of the gravitational field or the typical range of interactions carried by that component of the field. As an extension of previous works, we mainly focus on the Solar System and stellar tests of the theory, and the constraints on \(\beta\) obtained by the present work is independent of the previous ones. In the Solar System, we investigate the effects of the NCSG on the perihelion shift of a planet, deflection of light, time delay at superior conjunction (SC) and inferior conjunction (IC), and the Cassini experiment by modeling new observational results and adopting new datasets. In the binary pulsars system, based on the observational data sets of four systems of binary pulsars, PSR B1913+16, PSR B1534+12, PSR J0737-3039, and PSR B2127+11C, the secular periastron precessions are used to constrain this theory. These effects in the scale of the Solar System and binary pulsars were not considered in previous works. We find that the lower bounds given by these experiments are \(\beta \simeq 10^{-9} \sim 10^{-10}\) m⁻¹, considerably smaller than those obtained in laboratory experiments. This confirms that experiments and observations at smaller scales are more favorable for testing the NCSG theory.
The effects of a nonminimally coupled curvature-matter model of gravity on a perturbed Minkowski metric are presented. The action functional of the model involves two functions f1(R) and f2(R) of the Ricci scalar curvature R. This work expands upon previous results, extending the framework developed there to compute corrections up to order O(1/c4) of the 00 component of the metric tensor. It is shown that additional contributions arise due to both the nonlinear form f1(R) and the nonminimal coupling f2(R), including exponential contributions that cannot be expressed as an expansion in powers of 1/r. Some possible experimental implications are assessed with application to perihelion precession.
In the work of Hohmann et al. [Phys. Rev. D 88, 084054 (2013)], the authors worked out the parametrized post-Newtonian (PPN) parameters γ and β of a scalar-tensor theory with an arbitrary coupling function and a generic potential, and they found that these two PPN parameters depend on the radial distance r from the Sun, γ(r) and β(r). Based on the assumption that measurements on the PPN parameters can be characterized by the shortest distance to the Sun, the authors obtained their best constraints on the model parameters of the scalar-tenor theory by light deflection observation and the Cassini tracking experiment. However, as the authors stated, this approach might not be rigorous. In the present work, we physically model astronomical observations and physical experiments by calculating the null and timelike geodesics in the scalar-tensor theory. We show that, contrary to the results in the previous work, the light deflection and the Cassini tracking cannot distinguish the scalar-tensor theory from general relativity. We also investigate the additional advances in perihelia caused by the largest correction of the scalar field on the Newtonian potential. Since this correction has a Yukawa-like form, we obtain very much improved lower bounds on the model parameters by using current upper limits on the Yukawa parameters.
As an extension of previous works on classical tests of a braneworld model which is called as the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution, and as an attempt to find more stringent constraints on this model, we investigate its effects on physical experiments and astronomical observations conducted in the Solar System by modeling new observable effects and adopting new datasets. First, we investigate gravitational time delay at inferior conjunction (IC) caused by the braneworld model, which was not considered in previous works, because these measurements are not affected by the solar corona noise. Second, the Cassini superior conjunction (SC) experiment is, for the first time, used to test the DMPR model. Third, compared to previous works, we refine the model, which confronts the perihelion shift induced by the braneworld model with modern Solar System ephemerides INPOP10a (IMCCE, France) and EPM2011 (IAA RAS, Russia). The correction of DMPR solution to Einstein's general relativity (GR) in the four-dimensional spacetime can be characterized by a constant bulk "tidal charge" parameter Q, which is confined in the present work. We find that time delay experiment at IC is independent of Q and not suitable for testing the braneworld model. However, the Cassini SC experiment and modern Solar System ephemerides can give better upper bounds on Q: (1) |Q|≤ 1.2 × 107m2 by Cassini, and (2) |Q|≤ 61m2 based on the supplementary advances of the perihelia provided by INPOP10a and |Q|≤ 3.0 × 102m2 based on the ones of EPM2011. The latter upper bounds are improved to be tighter than the ones of previous works by at least two orders of magnitude. Besides, the stronger constraints on the brane tension are given by the modern ephemerides, which are ≥ 3.1 × 105MeV4 for INPOP10a and ≥ 6.2 × 104MeV4 for EPM2011. These improved upper bounds mean that the Solar System tests can serve as a good testbed for high dimensional theories.
We give more than 10 examples based on astronomical observations showing that dark energy acts not only on large scales but also on small scales. In particular, we present several independent arguments that the average Earth-Sun distance increases by about 5 m/yr. Such a large recession speed cannot be explained by the solar wind, tidal forces, plasma outbursts from the Sun, or by the decrease of the Solar mass due to nuclear reactions. We also discuss possible reasons for disagreement with other authors, who propose much smaller values.
As a generalization of Einstein’s general relativity (GR), the f(R, T) gravity replace the gravitational Lagrangian of GR with an arbitrary function of the Ricci scalar R and of the trace of the stress-energy tensor T. It can induce an extra acceleration a
E in the dynamics of massive test particles due to the physical coupling between matter and geometry. In this work, we confront this extra acceleration with planetary motions in the solar system. Using the supplementary advances in the perihelia provided by current INPOP10a and EPM2011 ephemerides, we obtain new upper limits on a
E when the uncertainty of the Sun’s quadrupole moment and the Lense-Thirring effect due to the Sun’s angular momentum are properly taken into account. These two factors were mostly absent in previous works dealing with a
E. We find that INPOP10a yields the upper limit as a
E=(−0.04±4.81)×10−15 m s −2 and EPM2011 gives a
E=(0.06±1.58)×10−15 m s −2. Both of them are improved at least by about 10 times than previous results obtained in the solar system and they are smaller than the results given by fitting rotation curves of galaxies by about 4 orders of magnitude. This discrepancy of a
E on these scales seems to imply that its effects might be screened in high density regions.
