REVIEW
Third post-Newtonian accurate generalized quasi-Keplerian parametrization for compact binaries in eccentric orbits
General Relativity and Quantum Cosmology · Submitted 13 Jul 2004 · 33 references
Pith's verdict: A careful, fully explicit 3PN quasi-Keplerian parametrization in both ADM and harmonic coordinates; the algebra is long but the cross-gauge agreement on n and Φ is a real check, not just a formality.
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Referee report
The paper
The paper claims
The paper derives a Kepler-style description of eccentric binary orbits accurate to third post-Newtonian order, with every orbital element written explicitly in terms of the orbit's conserved energy and angular momentum.
The reading
What carries the argument
The load-bearing device is the turning-point factorization. Because $ṙ^2$ and $dφ/ds$ (with $s = 1/r$) both come out as polynomials of degree seven in $s$ at 3PN order, the two positive roots $s_-$ and $s_+$ that survive as $1/c → 0$ can be read as the periastron and apastron. Writing $a_r = (s_- + s_+)/(2 s_- s_+)$ and $e_r = (s_- - s_+)/(s_- + s_+)$ turns the radial integral into the standard Kepler-like form and yields the radial period $P$, hence the mean motion $n = 2π/P$. The angular motion is handled by evaluating the $dφ/ds$ integral between the same two roots to get $Φ$, then introducing a third eccentricity $e_φ$ and choosing its PN corrections so that no $sin v$ term survives in the angle equation — the requirement that fixes $e_φ$ uniquely and reproduces the Keplerian structure at first PN order. Two consistency checks carry the weight of the algebra: $ṙ^2$ and $φ̇^2$ recomputed from the parametrization are compared against the same quantities computed from the Hamiltonian equations of motion (ADM) or from the conserved $E$ and $J$ (harmonic), and both agree to 3PN order.
Extended reading notes
Core claim
The central claim is that the 3PN-accurate conservative equations of motion for a non-spinning compact binary in an eccentric orbit admit a generalized quasi-Keplerian representation of exactly the same structural shape as the 2PN one: $r = a_r(1 - e_r cos u)$; a Kepler equation $l = n(t-t_0) = u - e_t sin u + (g_{4t}/c^4 + g_{6t}/c^6)(v-u) + (f_{4t}/c^4 + f_{6t}/c^6) sin v + (i_{6t}/c^6) sin 2v + (h_{6t}/c^6) sin 3v$; and an angle equation $2π(φ-φ_0)/Φ = v + (f_{4φ}/c^4 + f_{6φ}/c^6) sin 2v + (g_{4φ}/c^4 + g_{6φ}/c^6) sin 3v + (i_{6φ}/c^6) sin 4v + (h_{6φ}/c^6) sin 5v$, with $v = 2 arctan[((1+e_φ)/(1-e_φ))^{1/2} tan(u/2)]$. All elements — $a_r$, $e_r^2$, $n$, $e_t^2$, $Φ$, $e_φ^2$ — and all twelve orbital functions are written out explicitly in terms of $E$, $h$ and $η$ (Eqs. 20 and 25), together with the PN relations linking the three eccentricities (Eqs. 21 and 26). A second, independent claim is that the mean motion $n$ and the periastron advance per revolution $Φ$ come out identical in ADM-type and harmonic coordinates to 3PN order, which the authors present as a nontrivial confirmation of the expectation that these two quantities, expressed through gauge-invariant $E$ and $h$, should be coordinate-independent. From that invariance they extract gauge-invariant expressions for the dimensionless energy $E/c^2$ and squared angular momentum $(hc)^2$ in terms of $x = (GMn/c^3)^{2/3}$ and $k' = (Φ-2π)/(6π)$, generalizing the circular-orbit energy–frequency relation to eccentric orbits.
Load-bearing premise
The whole construction rests on $ṙ^2$ and $dφ/ds$ remaining polynomials of degree seven in $s = 1/r$ at 3PN order, which in harmonic coordinates holds only after adopting a specific coordinate transformation to remove logarithmic terms and a specific value for the regularization ambiguity — both taken from earlier work rather than derived here.
Editorial extensions
If this is right
- Search templates for gravitational waves from inspiralling eccentric compact binaries can be extended from the existing 2.5PN treatment to a fully 3.5PN-accurate orbital description.
- The explicit 3PN orbit supplies the input needed to compute $O(1/c^{11})$ corrections to orbit-averaged far-zone fluxes for eccentric binaries, once those fluxes are available.
- Because $n$ and $Φ$ are gauge invariant, eccentric orbits can be characterized by quantities that do not depend on the coordinate system, giving a cleaner post-Newtonian diagnostic for comparing numerical-relativity simulations against PN predictions.
- The parametrization provides the analytic solution needed to extend the relativistic binary-pulsar timing formula beyond its current PN order, which matters for long-baseline timing of systems such as the double pulsar.
- The gauge-invariant relations in Eq. (28) generalize the circular-orbit energy–frequency relation to eccentric orbits, opening the way to 3PN expressions for $dx/dt$ and $dk'/dt$ in terms of $x$ and $k'$.
Reading between the lines
- The identical form of $n(E,h)$ and $Φ(E,h)$ in two coordinate systems is the paper's strongest internal evidence; a reader can treat it as a numerical cross-check that a bug in either derivation would almost certainly break.
- Because the parametrization is purely conservative, the elements are constants here; the authors note that with radiation reaction switched on they become slowly evolving variables, which is what would make the construction usable inside an adiabatic inspiral template.
- The degree-seven polynomial structure in $s = 1/r$ is what makes the whole approach work; if a future 4PN treatment introduces non-polynomial terms (as logarithms already do at 3PN in harmonic coordinates before the coordinate transformation), the turning-point method would need to be rethought rather than merely extended.
- The eccentricity relations in Eqs. (21) and (26) mean that a single chosen eccentricity (say $e_r$) fixes the other two; a reader comparing PN eccentricity definitions across the literature should expect offsets of PN order, not agreement.
Original abstract
We present Keplerian-type parametrization for the solution of third post-Newtonian (3PN) accurate equations of motion for two non-spinning compact objects moving in an eccentric orbit. The orbital elements of the parametrization are explicitly given in terms of the 3PN accurate conserved orbital energy and angular momentum in both Arnowitt, Deser, and Misner-type and harmonic coordinates. Our representation will be required to construct post-Newtonian accurate `ready to use' search templates for the detection of gravitational waves from compact binaries in inspiralling eccentric orbits. Due to the presence of certain 3PN accurate gauge invariant orbital elements, the parametrization should be useful to analyze the compatibility of general relativistic numerical simulations involving compact binaries with the corresponding post-Newtonian descriptions. If required, the present parametrization will also be needed to compute post-Newtonian corrections to the currently employed `timing formula' for the radio observations of relativistic binary pulsars.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We present Keplerian-type parametrization for the solution of third post-Newtonian (3PN) accurate equations of motion for two non-spinning compact objects moving in an eccentric orbit. The orbital elements of the parametrization are explicitly given in terms of the 3PN accurate conserved orbital energy and angular momentum in both Arnowitt, Deser, and Misner-type and harmonic coordinates. Our representation will be required to construct post-Newtonian accurate `ready to use' search templates for the detection of gravitational waves from compact binaries in inspiralling eccentric orbits. Due to the presence of certain 3PN accurate gauge invariant orbital elements, the parametrization should be useful to analyze the compatibility of general relativistic numerical simulations involving compact binaries with the corresponding post-Newtonian descriptions. If required, the present parametrization will also be needed to compute post-Newtonian corrections to the currently employed `timing formula' for the radio observations of relativistic binary pulsars.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We present Keplerian-type parametrization for the solution of third post-Newtonian (3PN) accurate equations of motion for two non-spinning compact objects moving in an eccentric orbit. | contribution 1.00 | 0.95 | 0.56 | asserted 1.00 |
| s1 | The orbital elements of the parametrization are explicitly given in terms of the 3PN accurate conserved orbital energy and angular momentum in both Arnowitt, Deser, and Misner-type and harmonic coordinates. | contribution 0.49 | 0.92 | 0.17 | asserted 1.00 |
| s2 | Our representation will be required to construct post-Newtonian accurate `ready to use' search templates for the detection of gravitational waves from compact binaries in inspiralling eccentric orbits. | future work 0.55 | 0.21 | 0.21 | asserted 0.73 |
| s3 | Due to the presence of certain 3PN accurate gauge invariant orbital elements, the parametrization should be useful to analyze the compatibility of general relativistic numerical simulations involving compact binaries with the corresponding post-Newtonian descriptions. | interpretation 0.84 | 0.24 | 0.08 | hedged possibility 0.93 |
| s4 | If required, the present parametrization will also be needed to compute post-Newtonian corrections to the currently employed `timing formula' for the radio observations of relativistic binary pulsars. | future work 0.67 | 0.13 | 0.06 | hedged possibility 0.96 |
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Figures
Figures reproduced from arXiv:gr-qc/0407049 by the authors.
References
How later papers used it
108 later papers cite it
4 later papers by other authors are listed below: 4 used its method or tool and 1 compared its own results with it. 1 of them appears under more than one label. 2 more papers by the same authors are listed: 1 built on it and 1 used its method or tool.
Builds on it 1 paper · 1 by the same authors
By the same authors
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Computed 4PN order corrections to this paper's 3PN-accurate generalized quasi-Keplerian parametric solution in Arnowitt, Deser, and Misner coordinates.
Generalized quasi-Keplerian solution for eccentric, non-spinning compact binaries at 4PN order and the associated IMR waveform (2021) (same authors) · 1.00 · paraphrased: the licence does not allow quoting
Uses its method or tool 5 of 36 papers with this label · 1 by the same authors
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Followed this paper's well-explained method to obtain the quasi-Keplerian parametrization, which it briefly summarized.
Spin effects in gravitational waveforms and fluxes for binaries on eccentric orbits to the third post-Newtonian order (2023) · 1.00 · paraphrased: the licence does not allow quoting
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Following another work, used this paper's formalism to obtain a PN estimate for the eccentricity.
Anomalies in the gravitational recoil of eccentric black-hole mergers with unequal mass ratios (2021) · 1.00 · paraphrased: the licence does not allow quoting
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Utilized this paper's 3PN accurate quasi-Keplerian orbital parametrization.
Gravitational Waves from the Inspiral of Supermassive Black Holes in Galactic-scale Simulations (2019) · 1.00 · paraphrased: the licence does not allow quoting
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We employ similar techniques which allowed to obtain a simple parametrization for the solution of Post Newtonian accurate equations of motion for compact binaries in eccentric orbits [ref] .
Testing modified gravity via Yukawa potential in two body problem: Analytical solution and observational constraints (2022) · Introduction · 0.93
By the same authors
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We let BH binaries move in 3PN-accurate precessing eccentric orbits with the help of generalized quasi-Keplerian parametrization [ref] , where the 3PN-accurate description incorporates $(v/c)^6$-order general relativistic corrections to Newtonian motion.
Pulsar timing array signals induced by black hole binaries in relativistic eccentric orbits (2020) (same authors) · Introduction · 0.99
Compares with it 1 of 5 papers with this label
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Recovered this paper's results to 2PN in the nonspinning case.
Spin effects in gravitational waveforms and fluxes for binaries on eccentric orbits to the third post-Newtonian order (2023) · 0.97 · paraphrased: the licence does not allow quoting
How the literature uses it
83 arXiv papers cite this in 177 sentences
Papers citing it · 98 sentences without a confident label
Builds on it 1 paper
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This paper computes 4PN order corrections to the 3PN-accurate generalized quasi-Keplerian parametric solution of Ref. [ref] in the Arnowitt, Deser, and Misner (ADM) coordinates.
Generalized quasi-Keplerian solution for eccentric, non-spinning compact binaries at 4PN order and the associated IMR waveform · Introduction · 1.00
Uses its method or tool 24 papers
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We use the 3 PN conservative quasi-Keplerian orbit equations [ref] , combined with the 2 PN evolution of the orbital elements [ref] to construct adiabatic PN waveforms, determined by four independent initial parameters.
Comparisons of eccentric binary black hole simulations with post-Newtonian models · Introduction · 1.00
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Anyway, as the spins do not precess, the quasi-Keplerian parameterisation [ref] can be employed to obtain a parametric solution to the dynamics.
Aligned Spins: Orbital Elements, Decaying Orbits, and Last Stable Circular Orbit to high post-Newtonian Orders · Introduction · 0.96
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In this section, we follow closely the paper [ref] [ref] on the eccentric PN model since only the early-stage inspiral phase is considered in our case.
The GWs from the S-stars revolving around the SMBH at Sgr A* · The GWs from eccentric BBHs system · 0.99
Uses its data or values 5 papers
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The explicit expressions of $E$ and $h$ up to the 2PN order can be found in Eqs. (23a) – (23h) in Ref. [ref] .
Analytical coordinate time at the second post-Newtonian order · Preliminaries · 0.89
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+ 1/c^2H_1(r,p̂) +1/c^4 H_2(r,p̂) +1/c^6 H_3(r,p̂) +1/c^8 H_4(r,p̂) , where the explicit expressions for the 1PN, 2PN and 3PN contributions are given in Eq. (7) of Ref. [ref] .
Generalized quasi-Keplerian solution for eccentric, non-spinning compact binaries at 4PN order and the associated IMR waveform · Incorporating local-in-time 4PN Hamiltonian: generalized quasi-Keplerian solution · 0.90
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In ADM coordinates, the 3PN-accurate expressions for the orbital elements read [ref]
Comparison Between Self-Force and Post-Newtonian Dynamics: Beyond Circular Orbits · The generalized quasi-Keplerian representation · 0.83
Compares with it 5 papers
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It should be obvious that the resulting 4PN order $Φ$ expression depends on $E, h$ and $η$ and we have verified that our expression is consistent with Eq. (20-k) in Ref. [ref] .
Generalized quasi-Keplerian solution for eccentric, non-spinning compact binaries at 4PN order and the associated IMR waveform · Incorporating local-in-time 4PN Hamiltonian: generalized quasi-Keplerian solution · 1.00
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In the nonspinning case, we recover the results in Ref. [ref] to 2PN, at which the structure of the 3PN spin contribution is similar to the 2PN nonspinning contribution.
Spin effects in gravitational waveforms and fluxes for binaries on eccentric orbits to the third post-Newtonian order · Quasi-Keplerian parametrization · 0.97
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We have checked our expressions for $r$ and $ϕ̇$, as well as the 3 PN Kepler equation, by deriving them from the orbital elements in terms of $E$ and $h$ [ref] , and comparing with the explicit expressions in terms of $n$ and $e_t$ [ref] .
Comparisons of eccentric binary black hole simulations with post-Newtonian models · Eccentric post-Newtonian model · 0.95
Cites it as background 33 papers
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(Reference [ref] also includes the corresponding 3PN QK representation of [ref] for nonspinning systems in harmonic coordinates.) It may be worth noting that the QK representation presented in [ref] is in harmonic coordinates or more specifically in modified harmonic (MH) coordinates that were introduced to remove the presence of logarithmic terms in expressions for mass quadrupole moment at 3PN order [ref] and have been extensively used in numerous efforts focusing on modeling compact binary inspirals in elliptical orbits [ref] . 5pt The QK representation involves connecting variables describing compact binaries in general orbits to those characterizing the orbit one wishes to specialize to.
Spin effects in Spherical Harmonic Modes of Gravitational Waves from Eccentric Compact Binary Inspirals · quasi-keplerian representation · 0.83
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These extensions, detailed in Refs. [ref] , may be referred to as the `generalized quasi-Keplerian' parametric solution for describing PN-accurate orbital dynamics of compact binaries in eccentric orbits.
Generalized quasi-Keplerian solution for eccentric, non-spinning compact binaries at 4PN order and the associated IMR waveform · Keplerian type solution at 4PN order · 0.83
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Indeed, the quasielliptic motion was studied using an elegant generalization of the Kepler solution to first post-Newtonian (1PN) order, dubbed the quasi-Keplerian (QK) parametrization, which was introduced by Damour and Deruelle [ref] , and generalized up to 3PN order [ref] and partially to 4PN order [ref] .
Quasi-Keplerian parametrization for compact binaries on hyperbolic orbits in scalar-tensor theories at second post-Newtonian order · Introduction · 0.88
Discussion
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