Intro Review Tides Octupoles EOB Summary
Self-force calculations:synergies and invariants
Sam R Dolan
University of Sheffield, UK.
Perturbation Methods in GR @ Fields Institute, 20th May 2015.
Intro Review Tides Octupoles EOB Summary
Overview
1 Motivation
GW astronomy with Adv. LIGO
2 Synergies: a review from 2012
ISCO shift and periastron advanceCalibrating EOB
3 Tides
Asymptotic matched expansionsInvariants for circular orbitsOctupoles
4 Effective One-Body theory
Tidally-interacting neutron stars
5 Prospects
Eccentric orbits. Kerr.
Intro Review Tides Octupoles EOB Summary
“Large Two Forms”
Art Gallery of Ontario
Fµνωµ ∧ ων
“Large Two-Forms”
Fields Institute
Intro Review Tides Octupoles EOB Summary
“Large Two Forms”
Art Gallery of Ontario
Fµνωµ ∧ ων
“Large Two-Forms”
Fields Institute
Intro Review Tides Octupoles EOB Summary
Motivation: the general 2-body problem in relativity
Intro Review Tides Octupoles EOB Summary
Motivation: the general 2-body problem in relativity
Effective One-Body (EOB) model [Buonanno & Damour 1999].
Intro Review Tides Octupoles EOB Summary
Motivation: gravitational-wave astronomy
Intro Review Tides Octupoles EOB Summary
Self-Force: Two complementary viewpoints
accelerated motion on abackground spacetime
µ~ag = ~Fself
m
geodesic motion in a perturbedregular vacuum spacetimeg + hR
µ~ag+hR = 0
Intro Review Tides Octupoles EOB Summary
Self-Force ⇔ motion in a regular perturbed spacetime
Detweiler-Whiting split (’03):
h = hR + hS
R for Radiative / Regular
S for Symmetric / Singular
Motion of non-spinning compact body is geodesic ingR = g + hR.
We can compute hR at first-order O(µ/M), up to gaugefreedom,
hµν → hµν + ξ(µ;ν)
Intro Review Tides Octupoles EOB Summary
Self-Force ⇔ motion in a regular perturbed spacetime
Detweiler-Whiting split (’03):
h = hR + hS
R for Radiative / Regular
S for Symmetric / Singular
Motion of non-spinning compact body is geodesic ingR = g + hR.
We can compute hR at first-order O(µ/M), up to gaugefreedom,
hµν → hµν + ξ(µ;ν)
Intro Review Tides Octupoles EOB Summary
Three (related) methods for GSF calculations
1 Worldline integral (MiSaTaQuWa equation, schematically):
F selfa = local terms+µ2uµuν
∫ τ−
−∞∇[αGµ]νµ′ν′(z(τ), z(τ ′)uµ
′uν′dτ ′
2 Mode sum regularization: hretab =
∑ilm h
(i)lmab Y
(i)lm (θ, φ)
F aself =∞∑`=0
[F `ret(p)−AL−B − C/L
]−D
where L = l + 1/2.
3 Effective source / puncture schemes hR = h− hS
F aself = −µ2
(gab + uaub
) (2hRbc;d − hRcd;b
)ucud.
Intro Review Tides Octupoles EOB Summary
Three (related) methods for GSF calculations
1 Worldline integral (MiSaTaQuWa equation, schematically):
F selfa = local terms+µ2uµuν
∫ τ−
−∞∇[αGµ]νµ′ν′(z(τ), z(τ ′)uµ
′uν′dτ ′
2 Mode sum regularization: hretab =
∑ilm h
(i)lmab Y
(i)lm (θ, φ)
F aself =∞∑`=0
[F `ret(p)−AL−B − C/L
]−D
where L = l + 1/2.
3 Effective source / puncture schemes hR = h− hS
F aself = −µ2
(gab + uaub
) (2hRbc;d − hRcd;b
)ucud.
Intro Review Tides Octupoles EOB Summary
Harte (2012): Mechanics of extended masses in GR
A compact body with mass µM and spin s Gµ2/cundergoes parallel transport in the regular perturbedspacetime gR = g + hR.
ub∇bua = 0,
ub∇bsa = 0.
Intro Review Tides Octupoles EOB Summary
Example: spin precession on circular orbit
ψ ≡ Precession angle per orbit / 2π.
∆ψ at O(µ) is gauge invariant.
Intro Review Tides Octupoles EOB Summary
Synergies: Recap from Jan 2012
What were we excited about three years ago?
1 Comparison of gauge-invariant results with Post-Newtoniantheory (PN) and Numerical Relativity (NR):
ISCO shift due to conservative part of GSF
Perihelion advance of eccentric orbits
Benefits of using ‘symmetric mass-ratio’
2 Calibration of Effective One-Body (EOB) theory with GSF
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (I) The redshift invariant
Circular geodesic motion on Schwarzschild at radiusr > 3M ,
E =r − 2M√r(r − 3M)
µ,dE
dt= −Ft/ut0
The dissipative components, Ft and Fr, corresponding toenergy and angular momentum loss, are gauge-invariant(*).The conservative component Fr is gauge-dependent.Detweiler identified two quantities which are gaugeinvariant under transforms that respect the helicalsymmetry of the circular orbit.
1 Orbital frequency Ω ⇔ radius R ≡ (M/Ω2)1/3
2 Redshift z = 1/ut
Both defined w.r.t Schw. t coordinate of background.z(R) is a gauge-invariant relation.Results of Regge-Wheeler and Lorenz gauge calculationscompared by Detweiler, and Sago & Barack (’08).
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (II) The ISCO shift
Innermost stable circular orbit (ISCO) where dE/dr = 0.
For geodesic motion,
risco = 6M, Ωisco =(
63/2M)−1
.
The conservative part of GSF shifts the ISCO by O(µ).
∆Ωisco is invariant under gauge transformations thatrespect the helical symmetry of the circular orbit.
GSF prediction:
∆Ωisco
Ωisco= 0.4870µ/M
Barack & Sago, PRL 102, 191101 (2009), arXiv:0902.0573.
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (II) The ISCO shift
GSF prediction must be modified for comparison with PN,because Lorenz gauge is not asymptotically-flat(htt ∼ O(r0)).
Apply simple monopolar gauge transformation to get:
∆Ωisco
Ωisco= 1.2512µ/M
A challenge: can a resummed Post-Newtonian expansionmatch this strong-field result?
Challenge taken up in M. Favata, PRD 83, 024027 (2011),arXiv:1008.4622.
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (II) The ISCO shift
Table 1 in M. Favata, PRD 83, 024027 (2011),arXiv:1008.4622.
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (II) The ISCO shift on Kerr
(M + µ)Ωisco = MΩ(0)isco
(1 +
µ
MCΩ + . . .
)Isoyama et al., PRL 113, 161101 (2014).
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (III) The periastron advance
GR ⇒ periastron advance δ ≈ 6πM[(1−e2)p]
(e.g. 43” per century for Mercury).
Conservative part of GSF ⇒ ∆δ ∼ O(µ)
∆δ < 0 for all eccentric orbits
∆δ is gauge-invariant (within restricted class of gauges)
Numerical results in Barack & Sago, PRD 83, 084023(2011), arXiv:1101.3331.
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (III) Periastron advance
Periastron advance was compared between NR, PN, EOBand GSF in comparable mass regime 1/8 ≤ µ/M ≤ 1.
Le Tiec et al. PRL 107, 141101 (2011) [arXiv:1106.3278]
Remarkably, the GSF prediction works well even incomparable mass regime if we replace µ/M with symmetricmass ratio:
µ/M → ν = µM/(µ+M)2
Plots on next slide show K = Ωφ/Ωr = 1 + δ/(2π).
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (III) Periastron advance
From Le Tiec, Mroue, Barack, Buonanno, Pfeiffer, Sago andTaracchini, PRL 107, 141101 (2011), arXiv:1106.3278.
Intro Review Tides Octupoles EOB Summary
Synergies: Comparisons (III) Periastron advance
From Le Tiec, Mroue, Barack, Buonanno, Pfeiffer, Sago andTaracchini, PRL 107, 141101 (2011), arXiv:1106.3278.
Intro Review Tides Octupoles EOB Summary
Synergies: Calibration of EOB theory
Damour and collaborators have fed GSF results into theEOB model.Idea: Compare precession of small-eccentricity orbits atfirst-order in µ
Ω2r
Ω2φ
= 1− 6x+( µM
)ρ(x) +O
((µ/M)2
)where
x ≡ [(M + µ)Ωφ]2/3 .
PN theory gives the (weak-field) expansion
ρPN (x) = ρ2x2+ρ3x
3+(ρc4+ρlog4 lnx)x4+(ρc5+ρlog
5 lnx)x5+O(x6)
ρ2, ρ3 are given by 3PN.logarithmic contributions at 4PN and 5PN (ρlog
4 and ρlog5 )
have been derived by Damourρc4 and ρc5 were unknown in PN.
Intro Review Tides Octupoles EOB Summary
Synergies: Calibration of EOB theory
Using accurate GSF results, ρ2, ρ3, ρlog4 , ρlog
5 may betested, and the unknown parameters ρc4 and ρc5 may beconstrained:
ρc4 = 69+7−4, ρc5 = −4800+400
−1200, ρlog6 < 0.
Determination of ρ(x) in the range 0 ≤ x ≤ 1/6 gives firstinfo on strong-field behaviour of a combination of EOBfunctions a(u) and d(u) [where u = G(M + µ)/(c2rEOB)].
Advantage of GSF calibration: Both GSF and EOB splitnaturally into conservative and dissipative effects.
GSF data for ρ(x) may be fitted with simple 2-point Padeapproximation that also makes use of PN information.
Intro Review Tides Octupoles EOB Summary
Synergies: Calibration of EOB theory
From Barack, Damour and Sago, Phys. Rev. D 82, 084036 (2010)
[arXiv:1008.0935].
Intro Review Tides Octupoles EOB Summary
Invariants lead to synergies . . .
Key Questions:
1 Does hR still have unexplored latent physical content?Yes.
2 What are the physical gauge-invariant quantitiesassociated with a geodesic γ with tangent vector ua
on a regular vacuum black hole spacetime gRab?
Intro Review Tides Octupoles EOB Summary
Invariants lead to synergies . . .
Key Questions:
1 Does hR still have unexplored latent physical content?Yes.
2 What are the physical gauge-invariant quantitiesassociated with a geodesic γ with tangent vector ua
on a regular vacuum black hole spacetime gRab?
Intro Review Tides Octupoles EOB Summary
Asymptotic Matched Expansions
image from
Zlochower et al.,
arXiv:1504.00286.
Intro Review Tides Octupoles EOB Summary
Outer solution: Expansion about a worldline
Detweiler ’05: In THZ coordinates t, xi
gab = ηab + 2Hab + 3Hab +O(r4/R4)
with quadrupole part
2Habdxadxb = Eijxixj(dt2 + δkldx
kdxl) +4
3εklmBmi xlxidtdxk
and octupole part 3Habdxadxb =
−1
3E(ijk)x
ixjxk(dt2 + δkldx
kdxl)
+1
2εkpqBqijx
pxixjdtdxk +
−20
21
[Eij0xixjxk −
2
5r2Eik0x
i
]dtdxk
+5
21
[εjpqBqk0xix
pxk − 1
5r2εpqiBjq0xp
]dxidxj
Intro Review Tides Octupoles EOB Summary
Inner solution: Tidally-perturbed black hole
A tidally-perturbed BH can be written
gab = gSchwab + 2hab + 3hab +O(r4/R4)
with quadrupole part
2habdxadxb = −Eijxixj
[(1− 2µ/r)2dt2 + dr2 + (r2 − 2µ2)dΩ2
]+
4
3εkpqBqi x
pxi(1− 2µ/r)dtdxk
and octupole part. . .
Intro Review Tides Octupoles EOB Summary
Matching
Match in buffer regime µ r M
Analyze O(µ) parts
Coordinate + gauge subtleties (see e.g. Poisson;Johnson-McDaniel; Pound)
Key claim: The ‘external multipole moments’E(ijk), Eij0, etc., are those computed in regular perturbed
spacetime g + hR.
Intro Review Tides Octupoles EOB Summary
Tidal dynamics?
Consider compact body with linear and angularmomentum pa and sa and electric & magnetic quadrupolemoments Qab(E) and Qab(B)
Hartle & Thorne (’85) used a matched asymptoticexpansion to obtain
dpidτ
= −Biasa −1
2EiabQab(E)
dsidτ
= −εiabQa(E)cEcb − 4
3εiabQ
a(B)cB
cb
Role for external quadrupole and octupole tidal tensors
BH : quadrupole moments are small, Qab(E) ∼ µ3a2 ∼ µ5
Neutron stars : not necessarily so.
Intro Review Tides Octupoles EOB Summary
Tidal effects
Introduce electric- and magnetic-type tidal tensors:
Eab = Racbducud
Bab = R∗acbducud
where ∗ is (left) Hodge dual.
Eab generates geodesic deviation:
D2Xa
dτ2= −EabXb
Bab generates differential precession . . .
∆Ωa = BabXb
. . . and Papapetrou-Pirani force on a gyroscope
Dpa
dτ= −Babsb
Intro Review Tides Octupoles EOB Summary
Tidal effects
Introduce electric- and magnetic-type tidal tensors:
Eab = Racbducud
Bab = R∗acbducud
where ∗ is (left) Hodge dual.
Eab generates geodesic deviation:
D2Xa
dτ2= −EabXb
Bab generates differential precession . . .
∆Ωa = BabXb
. . . and Papapetrou-Pirani force on a gyroscope
Dpa
dτ= −Babsb
Intro Review Tides Octupoles EOB Summary
Tidal effects
Introduce electric- and magnetic-type tidal tensors:
Eab = Racbducud
Bab = R∗acbducud
where ∗ is (left) Hodge dual.
Eab generates geodesic deviation:
D2Xa
dτ2= −EabXb
Bab generates differential precession . . .
∆Ωa = BabXb
. . . and Papapetrou-Pirani force on a gyroscope
Dpa
dτ= −Babsb
Intro Review Tides Octupoles EOB Summary
Tidal effects
Electric- and magnetic-type tidal tensors are . . .
Transverse: Babub = 0 = Eabub
Symmetric: Eab = Eba, Bab = BbaTraceless: Baa = 0, Eaa = 0 (in vacuum)
⇒ 2× 5 = ten degrees of freedom, like Weyl tensor
Introduce an orthonormal triad eai on γ anddefine 3× 3 tidal matrices:
Eij = Eabeai ebj , Bij = Babeai ebj
Intro Review Tides Octupoles EOB Summary
Tidal effects
Electric- and magnetic-type tidal tensors are . . .
Transverse: Babub = 0 = Eabub
Symmetric: Eab = Eba, Bab = BbaTraceless: Baa = 0, Eaa = 0 (in vacuum)
⇒ 2× 5 = ten degrees of freedom, like Weyl tensor
Introduce an orthonormal triad eai on γ anddefine 3× 3 tidal matrices:
Eij = Eabeai ebj , Bij = Babeai ebj
Intro Review Tides Octupoles EOB Summary
Tidal effects
3× 3 symmetric matrices Eij & Bij have
3 real eigenvalues
3 orthogonal eigenvectors
Traceless condition:
λE1 + λE2 + λE3 = 0 = λB1 + λB2 + λB3
Two orthogonal eigenbases define three Euler angles
Seven ‘intrinsic’ degrees of freedom in eigenvalues/vectorsof tidal matrices (2 + 2 + 3).
Three remaining degrees of freedom depend on choice oftriad along γ.
Could use parallel transport to define a preferred triadon γ⇒ three more Euler angles.
Intro Review Tides Octupoles EOB Summary
Tidal effects
3× 3 symmetric matrices Eij & Bij have
3 real eigenvalues
3 orthogonal eigenvectors
Traceless condition:
λE1 + λE2 + λE3 = 0 = λB1 + λB2 + λB3
Two orthogonal eigenbases define three Euler angles
Seven ‘intrinsic’ degrees of freedom in eigenvalues/vectorsof tidal matrices (2 + 2 + 3).
Three remaining degrees of freedom depend on choice oftriad along γ.
Could use parallel transport to define a preferred triadon γ⇒ three more Euler angles.
Intro Review Tides Octupoles EOB Summary
Tidal effects
3× 3 symmetric matrices Eij & Bij have
3 real eigenvalues
3 orthogonal eigenvectors
Traceless condition:
λE1 + λE2 + λE3 = 0 = λB1 + λB2 + λB3
Two orthogonal eigenbases define three Euler angles
Seven ‘intrinsic’ degrees of freedom in eigenvalues/vectorsof tidal matrices (2 + 2 + 3).
Three remaining degrees of freedom depend on choice oftriad along γ.
Could use parallel transport to define a preferred triadon γ⇒ three more Euler angles.
Intro Review Tides Octupoles EOB Summary
Tidal effects
Alternatively, use the electric eigenbasis as the triad.
3 electric + 6 magnetic components - 2 traces = 7
Define relative precession three-vector Ωi = εijkΩjk,
Ωij = gabeai
Debjdτ
May also examine octupolar tensors
Eabc = Radbe;cudue, Babc = R∗adbe;cu
due
and resolve these in the electric eigenbasis.
cf. tidal tendexes and vortexes by Zimmerman et al.cf. gravitoelectromagnetism.
Intro Review Tides Octupoles EOB Summary
Tidal effects
Alternatively, use the electric eigenbasis as the triad.
3 electric + 6 magnetic components - 2 traces = 7
Define relative precession three-vector Ωi = εijkΩjk,
Ωij = gabeai
Debjdτ
May also examine octupolar tensors
Eabc = Radbe;cudue, Babc = R∗adbe;cu
due
and resolve these in the electric eigenbasis.
cf. tidal tendexes and vortexes by Zimmerman et al.cf. gravitoelectromagnetism.
Intro Review Tides Octupoles EOB Summary
Circular orbits
Define gauge-invariant relationships at O(µ) via
∆χ(y) = limµ→0
χ(y)− χ(y)
µ
where χ is the test-particle (µ = 0) function on BH
background, and y =(GMΩ/c3
)2/3is frequency-radius
Zero derivatives: Detweiler’s redshift invariant ∆U(’08)
First derivatives: spin precession invariant ∆ψ (’14)
Second derivatives: Three independent eigenvalues oftidal tensors ∆λE1 ,∆λ
E2 ,∆λ
B and one angle ∆χ.
Third derivatives: Octupolar invariants ∆E(ijk)
Intro Review Tides Octupoles EOB Summary
Octupoles!
Intro Review Tides Octupoles EOB Summary
Octupoles for circular orbits
Project Rabcd;eubud onto electric-quadrupolar eigenbasis,
i.e.χi0j... = χabc...e
ai u
becj
Three types of terms:
Eij0, Ei[j;k], and E(ijk),
Bij0, Bi[j;k], and B(ijk),
First two types are derived from quadrupole & dipoleinvariants
Intro Review Tides Octupoles EOB Summary
Octupoles for circular orbits
Eij0 : all components zero except
E130 = ω (E11 − E33) , B120 = −ω B23, B230 = ω B12.
Ei[jk] : all components zero except
E2[23] = E1[31] =1
2ωB23,
E3[31] = E2[12] = −1
2ωB12,
B1[12] = B3[23] =1
2ω (E11 − E33) ,
E(ijk) and B(ijk) :
7 new dof = 10 symmetrized components - 3 traces.
Intro Review Tides Octupoles EOB Summary
Symmetries for circular orbits
Triad:
ea1 points in radial / ‘electric-stretch’ eigendirection
ea2 points out of the plane
ea3 = εabcdubec1e
d2
Equatorial symmetry: Electric (magnetic) componentswith odd (even) number of ‘2’ components are zero.
Reversal symmetry: Electric and magnetic componentswith an odd number of ‘3’ components on the BHbackground are zero (but not in general).
Intro Review Tides Octupoles EOB Summary
Equatorial symmetry, general triad
Eij + iBij =
E11 iB12 E13
· E22 iB23
· · E33
Align triad with electric eigenbasis,
Eij + iBij =
E11 iB12 0· E22 iB23
· · E33
On black hole background,
Eij + iBij =
E11 iB12 0· E22 0· · E33
Intro Review Tides Octupoles EOB Summary
Equatorial symmetry: Electric (magnetic) componentswith odd (even) number of ‘2’ components are zero.
Just six components are non-zero on background:
E(111), E(122), E(133),
B(211), B(222), B(233).
Four components are zero on background due to reversalsymmetry:
E(311), E(322), E(333), B(123)
Three trace conditions:
E(111) + E(122) + E(133) = 0
B(211) + B(222) + B(233) = 0
E(311) + E(322) + E(333) = 0
Intro Review Tides Octupoles EOB Summary
A classification: conservative / dissipative
For circular orbits,
∇n Conservative Dissipative
n = 0 Un = 1 ψ F3
n = 2 E11, E22, B12 B23
n = 3 E(111), E(122), B(211), B(222) E(311), E(322), B(123)
The dissipative quantities:
may be computed from 12 (hret − hadv)
“do not require regularization”
are zero on the background
have an odd number of ‘3’ legs
Intro Review Tides Octupoles EOB Summary
Results: PN series in y ≡ (GMΩ/c3)2/3
Redshift [Detweiler (2008)]:
∆U = −y − 2y2 − 5y
3+
(4132π2 − 121
3
)y4
+(−
1157
15− 128
5γ + 677
512π2 − 256
5log 2− 64
5log y
)y5
+ . . .
Spin precession [Dolan, Harte et al. (2014)]
∆ψ = y2 − 3y
3 − 152y4
+(− 6277
30− 16γ + 20471
1024π2 − 496
15log 2
)y5 − 8y
6+ . . .
Tidal invariants [Dolan, Nolan et al. (2014); Bini & Damour (2014)]
∆E11 = 2y3
+ 2y4 − 19
4y5
+(
2273− 593
256π2)y6
+(− 71779
4800+ 768
5γ − 719
256π2
+ 15365
log 2)y7
+ . . .
∆E22 = −y3 − 32y4 − 23
8y5
+(
12491024
π2 − 2593
48
)y6
+(− 362051
3200− 256
5γ + 1737
1024π2 − 512
5log 2
)y7
+ . . .
∆E33 = −y3 − 12y4
+ 618y5
+(
11231024
π2 − 1039
48
)y6
+(
12297119600
− 5125γ + 1139
1024π2 − 1024
5log 2
)y7
+ . . .
∆B12 = 2y7/2
+ 3y9/2
+ 594y11/2
+(
276124− 41
16π2)y13/2
+ . . .
∆B23 =
Intro Review Tides Octupoles EOB Summary
Results: PN series in y ≡ (GMΩ/c3)2/3
Octupoles [Nolan, Kavanagh, Dolan, Warburton, Wardell & Ottewill, arXiv:]
∆E(111) = −8y4
+ 8y5
+ 30y6 − ( 1711
6− 4681
512π2)y
7+
+( 136099
400− 6255
1024π2 − 2048
5γ − 4096
5log 2− 1024
5log y
)y8
+ . . .
∆E(122) = 4y4 − 7
3y5 − 9y
6+ ( 1369
8− 9677
2048π2)y
7+
+( 121369
7200+ 265
192π2
+ 10245γ + 2048
5log 2 + 512
5log y
)y8
+ . . .
∆E(133) = 4y4 − 17
3y5 − 21y
6+ ( 2737
24− 9047
2048π2)y
7 −
−( 2571151
7200− 14525
3072π2 − 1024
5γ − 2048
5log 2− 512
5log y
)y8
+ . . .
∆E(113) = 1285y13/2 − 108
5y15/2
+ 5125πy
8 − 46978105
y17/2
+ 379445
πy9
+ . . .
∆E(223) = − 325y13/2 − 18
5y15/2 − 128
5πy
8+ 8276
105y17/2 − 15242
315πy
9+ . . .
∆E(333) = − 965y13/2
+ 1265y15/2 − 384
5πy
8+ 38702
105y17/2 − 3772
105πy
9+ . . .
∆B(123) = 643y7
+ 365y8
+ 2563πy
17/2 − 534715
y9
+ 219715
πy19/2
+ . . .
∆B(211) = −8y9/2
+ 163y11/2 − 20y
13/2+ (− 677
2+ 5101
512π2)y
15/2+ . . .
∆B(222) = 6y9/2 − 4y
11/2+ 83
4y13/2
+ ( 10694− 7809
1024π2)y
15/2+ . . .
∆B(233) = 2y9/2 − 4
3y11/2 − 3
4y13/2
+ ( 2854− 2393
1024π2)y
15/2+ . . .
Intro Review Tides Octupoles EOB Summary
Results: PN series vs Numerical data (conservative)
Relative difference between the numerical data and successive truncations
of the relevant PN series for conservative components.
Intro Review Tides Octupoles EOB Summary
Results: PN series vs Numerical data (dissipative)
Relative difference between the numerical data and successive truncations
of the relevant PN series for dissipative components.
Intro Review Tides Octupoles EOB Summary
Results: Light-ring divergences
Divergence of the conservative octupolar invariants as the orbital radius
approaches the light-ring: z = 1 − 3M/r0.
Intro Review Tides Octupoles EOB Summary
Effective One-Body Theory
The Newtonian two-body problem may be reformulatedin terms of a single effective potential Veff with reducedmass
µ =m1m2
M, M = m1 +m2,
where
Veff =P 2φ
2µR2+ V (R)
Intro Review Tides Octupoles EOB Summary
Effective One-Body Theory
In EOB formalism there is a relativistic radial potential,
Weff =√A(R) (µ2 + (Pφ/R)2)
A(R) is a radial function where
A(R) ≈ 1 + 2V (R)/µ as R→∞ ,
A(R) ≈ 1− 2M/R as m1,m2 → 0
A(R) modified by
Finite mass-ratio ν ⇒ repulsion
Tidal polarizability κ(`)i : ⇒ attraction
Tidal effects modify the radial potential:
A(R; ν;κ(`)A ) = A0(R; ν) +AT (R;κ
(`)i )
Intro Review Tides Octupoles EOB Summary
Fig 1 in “Modeling the dynamics of tidally-interacting binary neutron stars
up to merger”, Bernuzzi, Nagar, Dietrich & Damour, Phys. Rev. Lett.
114, 161103 (2015), arXiv:1412.4553.
Intro Review Tides Octupoles EOB Summary
Effective One-Body Theory
Electric (+) tidal contribution (u = M/R)
A(+)T (u; ν) = −
∑`=2
[κ
(`)1 u2`+2A
(`+)1 + (1↔ 2)
]Tidal polarizability:
κ(`)i = 2k
(`)i
(mi/M
Ci
)2`+1 mj
mi
where k(`)i are the dimensionless Love numbers and Ci
are stars’ compactnesses
‘Resummed’ term
A(2+)i = 1 +
3u2
1− rlru+XiA
(2+)1SF1
(1− rlru)7/2+X2i A
(2+)2SF2
(1− rlru)4
Intro Review Tides Octupoles EOB Summary
Effective One-Body Theory
Effective Field Theory approach ⇒ terms Ai are built fromirreducible invariants
Je2 ≡ TrE2, Jb2 ≡ TrB2, Je3 ≡ TrE3, . . .
viaAJi =
√F (u)U−1J
U is redshift and F (u) is related to A(R).
Intro Review Tides Octupoles EOB Summary
EOB : Irreducible invariants
EOB + Effective Field Theory ⇒ model calibrated withscalar invariants
TrE2, TrB2, TrE3, E(abc)E(abc), etc.
May be obtained from our component invariants, e.g.,
K3+ = E(abc)E(abc)
= E2(111) + E2
(333) + 3(E2
(122) + E2(133) + E2
(311) + E2(322)
)−6E2
(130)
∆K3+
K3+= δK3+ + 2h00
Intro Review Tides Octupoles EOB Summary
EOB : Irreducible invariants
δK3+ = − 83
+ 35845y + 11848
675y2
+ (− 358190340500
+ 46811536
π2)y
3+
( 6147944832430000
− 79093192160
π2 − 2048
15γ − 4096
15log 2− 1024
15log y
)y4
+(− 759123028241
1020600000+ 431520437
11059200π2
+ 10707041575
γ + 354064225
log 2− 14587
log 3 + 5353521575
log y)y5 − 219136
1575πy
11/2
+( 12569905047667
2187000000− 1903269674027
1769472000π2 − 42147341
6291456π4
+ 181080056212625
γ − 123628168212625
log 2 + 7395335
log 3 + 90540028212625
log y)y6
+ 118163398165375
πy13/2
+ y7(
52369829422440012073990186120000000
− 4176344893416403990904320000
π2
+ 3512069844616039797760
π4 − 4143716714678
245581875γ + 1753088
1575γ2
− 6124042466966245581875
log 2 + 70123521575
γ log 2 + 70123521575
log2
2− 21435048930800
log 3 + 976562514256
log 5− 2071858357339245581875
log y
+ 17530881575
γ log y + 35061761575
log 2 log y + 4382721575
log2y − 32768
15ζ(3)
)+ 169822838237
245581875πy
15/2
+y8(
123440508676629175685507910812832430400000000
− 205165828703043199754214400000
π2 − 4004468043930067
11596411699200π4
+ 6403209826927357335219259375
γ − 819289024165375
γ2
+ 18668500151420029335219259375
log 2− 4048635776165375
γ log 2− 4434375616165375
log2
2− 4137804755289196196000
log 3 + 22744849
γ log 3
+ 22744849
log 2 log 3 + 11372449
log2
3− 88378906251111968
log 5 + 6300230470447357670438518750
log y − 819289024165375
γ log y
− 2024317888165375
log 2 log y + 11372449
log 3 log y − 204822256165375
log2y + 10678144
1575ζ(3)
)+(− 1048639996225198903
58998589650000π − 3506176
4725π3
+ 375160832165375
πγ + 750321664165375
π log 2 + 187580416165375
π log y)y17/2
+O(y9). (1)
Intro Review Tides Octupoles EOB Summary
EOB : Tidally-interacting binary neutron stars
Punchline of Bernuzzi et al. (2015) : Compare red and bluelines
Intro Review Tides Octupoles EOB Summary
Summary
The self-force approach yields various physical invariantsat O(µ/M)
Invariants allow for comparisons (with PN & NR) andcalibration (e.g. EOB)
Tidally-calibrated EOB models needed for (e.g.) Adv.LIGO data analysis for NS binaries
Frontiers:
Schwarzschild → Kerr BHs
Eccentric and non-equatorial orbits
Second-order self-force at O(µ2/M2)