130 Million Years ago, in a galaxy equally far away F. J. - - PowerPoint PPT Presentation

130 million years ago in a galaxy equally far away
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130 Million Years ago, in a galaxy equally far away F. J. - - PowerPoint PPT Presentation

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation 130 Million Years ago, in a galaxy equally far away F. J.


slide-1
SLIDE 1

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

130 Million Years ago, in a galaxy equally far away

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-2
SLIDE 2

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

130 Million Years ago, in a galaxy equally far away

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-3
SLIDE 3

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Gravitational radiation from neutron star merger

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-4
SLIDE 4

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

One needs to know...

◮ Nuclear physics ◮ Particle physics ◮ General relativity ◮ Numerical analysis . . .

So that requires a giant of physics Which is, of course, the chairman. (Need extra time to fit some slides)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-5
SLIDE 5

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

One needs to know...

◮ Nuclear physics ◮ Particle physics ◮ General relativity ◮ Numerical analysis . . .

So that requires a giant of physics Which is, of course, the chairman. (Need extra time to fit some slides)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-6
SLIDE 6

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

One needs to know...

◮ Nuclear physics ◮ Particle physics ◮ General relativity ◮ Numerical analysis . . .

So that requires a giant of physics Which is, of course, the chairman. (Need extra time to fit some slides)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-7
SLIDE 7

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Equation of State for modified gravity studies at neutron stars

Felipe J. Llanes-Estrada

Universidad Complutense de Madrid, Departamento de F´ ısica Te´

  • rica

Ongoing work in collaboration with Eva Lope Oter & Ivan Sayago (@UCM), Mark Alford and Andreas Windisch (@ WU St. Louis)

26th/6/2018 Strong and Electroweak Matter, Barcelona

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-8
SLIDE 8

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-9
SLIDE 9

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Outline

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-10
SLIDE 10

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Amazing: γ delayed 1.7sec in a 130 Mly travel

◮ Little matter in the way (Compton scattering): galaxy’s edge ◮ GWs and light have precisely the same speed to 10−15 ◮ But where does the delay come from?

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-11
SLIDE 11

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Amazing: γ delayed 1.7sec in a 130 Mly travel

◮ Little matter in the way (Compton scattering): galaxy’s edge ◮ GWs and light have precisely the same speed to 10−15 ◮ But where does the delay come from?

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-12
SLIDE 12

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Amazing: γ delayed 1.7sec in a 130 Mly travel

◮ Little matter in the way (Compton scattering): galaxy’s edge ◮ GWs and light have precisely the same speed to 10−15 ◮ But where does the delay come from?

Whether jet or fireball, the instant when matter becomes transparent is delayed arxiv:1711.03112

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-13
SLIDE 13

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

10−15!! and Einstein failed to find a Unified Field Theory...

(As this cartoon by Quino illustrates)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 14

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

LIGO is testing General Relativity

Post-Newtonian coeffs. constrained 103 better with their BH-BH than with earlier binary-pulsar orbital period measurement

LIGO scientific coll. PRL116 221101 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 15

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Coming to GW170817: Tidal deformability

Upper bound Λ = 2 3k2

  • (c2/G)(R/m)

5 ≤ 800 (low spin priors; could be 1400) Constraint on allowed equations of state... if you assume General Relativity

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 16

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Distinguishing Nuclear matter- from Gravitational- effects

The strong equivalence principle difficults assigning corrections to either T or G Example: cosmological constant Gµν + λgµν = 8πG c4 Tµν Same problem in neutron stars

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 17

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

So here an example from home

N-Star oscillation frequency against mass Can slide up or down the curve with both EOS and theory EITHER test the EoS OR test GR but not both

(F. Navarro from UCM et al.)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-18
SLIDE 18

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

R + aR2 gravity: N-star mass increased for sufficiently large a

R (km) 7.5 8 8.5 9 9.5 10 M (Msun) 0.5 1 1.5 2 2.5 3 3.5 4 4.5

GR a= - 0.001 a= - 0.01 a= - 0.03 a= - 0.05

R (km) 9 9.5 10 10.5 11 11.5 12 12.5 M (Msun) 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2

GR a= - 0.001 a= - 0.01 a= - 0.03 a= - 0.05

R (km) 10.5 11 11.5 12 12.5 13 13.5 14 14.5 M (Msun) 2 2.5 3 3.5

GR a= - 0.001 a= - 0.01 a= - 0.03 a= - 0.05

◮ State equations of Hebeler et al. APJ773:11 (2013) ◮ Matching to exterior Schwarzschild (careful: lot of energy

there)

◮ Find heavier stars

(M. Aparicio Resco et al., Phys. Dark Universe 2016; also works by Odintsov and coll. and Yazadjev & Doneva)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-19
SLIDE 19

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Outline

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-20
SLIDE 20

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

What we gain with NS mergers

Retarded metric for a linear wave (t′ = t − |x − y|/c) ¯ hαβ(t, x) = 4G c4

  • d3yTαβ(t′, y)

|x − y| Tαβ(t′, y), that’s us! T = T (0)

  • Perfect, isotropic EOS P(ρ))

+τ dissipative + T anisotropic

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-21
SLIDE 21

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

What we gain with NS mergers

Retarded metric for a linear wave (t′ = t − |x − y|/c) ¯ hαβ(t, x) = 4G c4

  • d3yTαβ(t′, y)

|x − y| Tαβ(t′, y), that’s us! T = T (0)

  • Perfect, isotropic EOS P(ρ))

+τ dissipative + T anisotropic

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-22
SLIDE 22

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Input to numerical relativity simulations

Quote off numerical relativity work (Parma-Louisiana 1605.03424) “The true EOS for nuclear matter in an environment similar to a neutron star is still not known. (...) We thus have to simulate the effect of different plausible EOSs on observable quantities, in the hope to learn about the EOS indirectly through observations.” Standard in that field: Akmal, Pandharipande and Ravenhall, PRC58 1804 (1998) (basically, Argonne potential + some 3-body force)

Also used: Skyrme-Lyon interaction (Douchin, Haensel arXiv:astro-ph/0111092), Hyperon EOS by Lackey, Nayyar, and Owen, PRD73 024021 (2006), Muller and Serot, PRC52 2072 (1995).

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-23
SLIDE 23

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Static observables: Mass and radius

Quark matter + B 1608.00602 Fogaca et al (Navarra) Neutron matter Argonne+Urbana+QMC 1307.5815 Gandolfi et al. Neutron matter (Skyrme+HFB) 1607.05943 Chamel

6 8 10 12 14 16 R (km) 0.5 1 1.5 2 2.5 M/Msun Free neutron gas ChEfT, no constraint Causal ChEfT

Neutron matter (EFT+dispersion) PRC85 012801 (2012) Dobado et al.

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 24

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

GW predictions hampered by EOS

For example, uncertainty in predicting the phase, but also O(15%) uncertainty in predicting the merging time, O(25%) uncertainty for the hmax amplitude, O(50%) uncertainty in the peak frequency emitted after merging, O(100%) uncertainty in the total radiated energy.

1605.03424; but not systematic uncertainties

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-25
SLIDE 25

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Can hadron physics control the EOS?

Check perturbative convergence Chiral counting of nucleon forces in medio

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-26
SLIDE 26

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Modern calculations in EFT+unitarity

Neutron stars: large Fermi momentum = ⇒ EFT with pions

Leading Order Vr=1 Op5 1 Vr=1 Next−to−Leading Order Op6 2 Next−to−Leading Order Vr=2 Op6

... 3.1 3.2 ...

(Lacour, Oller and Meissner Ann. Phys. 326 (2011) 241, consistent power counting in nuclear matter)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 27

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Changes of phase soften the EOS

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-28
SLIDE 28

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Changes of phase soften the EOS

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-29
SLIDE 29

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Changes of phase soften the EOS

P(ρ) will be below whatever Neutron Matter computation yields Anything “exotic” beyond neutrons is a softener

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-30
SLIDE 30

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

LO+NLO

Cutoff variation (450-600) MeV

Sammarruca et al. (INFN-Idaho) Proc. of Science Chiral Dynamics 15 026 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-31
SLIDE 31

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

NNLO

3-body force: local density approx. Not a full Bethe-Faddeev computation

Sammarruca et al. (INFN-Idaho) Proc. of Science Chiral Dynamics 15 026 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-32
SLIDE 32

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

NNLO+ part of N3LO

From N3LO only 2-body part (to add 3-body, need to refit triton)

Sammarruca et al. (INFN-Idaho) Proc. of Science Chiral Dynamics 15 026 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-33
SLIDE 33

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

One thing is sure

2-body 3-body This group will extend the 2-body force to N4LO soon (ask Entem)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-34
SLIDE 34

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

One thing is sure

2-body 3-body This group will extend the 2-body force to N4LO soon (ask Entem)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-35
SLIDE 35

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

So here is the competence

  • C. Drischler et al. (Schwenk) 1608.05615
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-36
SLIDE 36

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

So here is the competence

  • J. Hu et al. (Meissner) 1612.05433
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-37
SLIDE 37

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Neutron star cores beyond reliability of χpt

◮ Typically you cannot trust theory past kF ≃ 400 − 600 MeV ◮ But kF in heavy 2M⊙ stars could easily reach 800 MeV-1 GeV.

Sometimes: EoS extrapolated with polytrope functions P = cργ

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-38
SLIDE 38

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Outline

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-39
SLIDE 39

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Ren´ e Descartes taught us

The first was never to accept anything for true which I did not clearly know to be such; that is to say, carefully to avoid precipi- tancy and prejudice, and to com- prise nothing more in my judg- ment than what was presented to my mind so clearly and dis- tinctly as to exclude all ground

  • f doubt.
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-40
SLIDE 40

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

A little above nuclear density, e.g. NNLO Idaho EoS

50 100 150 200 250 300 ε(MeV/fm

3)

5 10 15 20 P (MeV/fm

3)

EoS Idaho Chiral

  • F. Sammarruca et al. PoS CD15 (2016) 026
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-41
SLIDE 41

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

But the bulk of a neutron star has higher density

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-42
SLIDE 42

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

How to use the EoS from asymptotically high density?

A.Kurkela et al., PRD 81 (2010) 105021

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-43
SLIDE 43

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Causality: cs ≤ c

4 8 12 16 ε (mπ

4)

0.3 0.6 0.9 1.2 1.5 (cs/c)

2

Causality limit cs<c Chiral Effective Theory Free neutron gas

(Note χEFT has repulsion built in: it exceeds c2

s = 1/3 but that’s ok)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-44
SLIDE 44

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Monotonicity

dP dǫ ≥ 0 → c2

s ≥ 0

(Less fundamental but credible: quarks are fermions)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-45
SLIDE 45

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

EOS from first principles + mass + tidal constraints

Kurkela et al. 1711.02644 (assumes General Relativity) (see slides of T. Gorda)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-46
SLIDE 46

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Outline

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-47
SLIDE 47

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

What we want to avoid

Simple parametrization interpolating the two bands Uncontrolled systematic error from the parametrization

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-48
SLIDE 48

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Advance from ǫ = 0 with Von Neumann’s rejection

Unbiased; inefficient but simple (less bugs)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-49
SLIDE 49

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Same through middle band interpolating low-high energy

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 50

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Fortran code

◮ Advance with random step & reject if outside the band; start

  • ver

◮ Parameters: Λlow for the chiral theory, ΛhighforpQCD

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-51
SLIDE 51

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Advantages of the method

◮ State of the art EoS that do not assume General

Relativity (ideal to check extensions thereof)

◮ Systematic errors from countings ◮ New information from QCD available? No

problem, we substitute our low-ǫ/high-ǫ bands

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-52
SLIDE 52

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Example: 10 EOS on a sparse grid on the stiff side

10 100 1000 10000 1e+05 ε(MeV/fm

3)

1×10 1×10

1

1×10

2

1×10

3

1×10

4

1×10

5

P (MeV/fm

3)

PRELIMINARY

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-53
SLIDE 53

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

How to deliver 100-1000 EoS candidates to a user?

◮ Give us the ǫ-grid,

we return P on it?

◮ We give a callable function and interpolate our

  • wn grid? (e.g. pdfs)

◮ We develop a web interface?

Or clean up and release the code? Send us an email with your needs!

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-54
SLIDE 54

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

How to deliver 100-1000 EoS candidates to a user?

◮ Give us the ǫ-grid,

we return P on it?

◮ We give a callable function and interpolate our

  • wn grid? (e.g. pdfs)

◮ We develop a web interface?

Or clean up and release the code? Send us an email with your needs!

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-55
SLIDE 55

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

How to deliver 100-1000 EoS candidates to a user?

◮ Give us the ǫ-grid,

we return P on it?

◮ We give a callable function and interpolate our

  • wn grid? (e.g. pdfs)

◮ We develop a web interface?

Or clean up and release the code? Send us an email with your needs!

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-56
SLIDE 56

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

How to deliver 100-1000 EoS candidates to a user?

◮ Give us the ǫ-grid,

we return P on it?

◮ We give a callable function and interpolate our

  • wn grid? (e.g. pdfs)

◮ We develop a web interface?

Or clean up and release the code? Send us an email with your needs!

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-57
SLIDE 57

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Are working on these things? consider...

Journal of Physics G focus issue Hadrons and Gravitational Waves after GW170817 Approved and open for submis- sions any day now

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-58
SLIDE 58

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Cosmocaixa is a shelter for theorists

Because there are no stars in Barcelona’s night sky

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-59
SLIDE 59

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

They are organizing the workshop

THANK YOU!

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

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SLIDE 60

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Equation of State for modified gravity studies at neutron stars

Felipe J. Llanes-Estrada

Universidad Complutense de Madrid, Departamento de F´ ısica Te´

  • rica

Ongoing work in collaboration with Eva Lope Oter & Ivan Sayago (@UCM), Mark Alford and Andreas Windisch (@ WU St. Louis)

26th/6/2018 Strong and Electroweak Matter, Barcelona

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-61
SLIDE 61

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Spare slides

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-62
SLIDE 62

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Effect of finite T?

◮ Mergers: temperatures of O(60) MeV ◮ At this level, T ∼ mπ ≪ mn (can use chiral counting at low ǫ) ◮ A. Dobado et al. PRC2002 teaches us that mρ, mσ are

unaffected

300 400 500 600 700 800 900 1000 Re

✁ ✂✄ ✄ ✄ ✄ ✄ ✄ ✄ ✄ ✄

spole

  • M

MeV

☎ ✆

250

200

150

100

50 m I

✝ ✞ ✟ ✟ ✟ ✟ ✟ ✟ ✟ ✟ ✟

s

e l

  • p
✠ ✡ ☛ ☞ ✌

2

V e M

T

  • 100 MeV

T

  • 200 MeV

T

  • 25 MeV

T

  • 100 MeV

T

  • 125 MeV

Pole evolution with Temperature:

pole

pole

Low energy dynamics controlled by M, not Γ: T is not the most urgent concern.

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-63
SLIDE 63

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Effect of finite T?

◮ Mergers: temperatures of O(60) MeV ◮ At this level, T ∼ mπ ≪ mn (can use chiral counting at low ǫ) ◮ A. Dobado et al. PRC2002 teaches us that mρ, mσ are

unaffected

300 400 500 600 700 800 900 1000 Re

✏ ✑✒ ✒ ✒ ✒ ✒ ✒ ✒ ✒ ✒

spole

✓ ✔

M

MeV

✓ ✕

250

200

150

100

50 m I

✖ ✗ ✘ ✘ ✘ ✘ ✘ ✘ ✘ ✘ ✘

s

e l

  • p
✙ ✚ ✛ ✜ ✢

2

V e M

T

100 MeV T

200 MeV T

25 MeV T

100 MeV T

125 MeV Pole evolution with Temperature:

pole

pole

Low energy dynamics controlled by M, not Γ: T is not the most urgent concern.

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-64
SLIDE 64

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Effect of finite T?

◮ Mergers: temperatures of O(60) MeV ◮ At this level, T ∼ mπ ≪ mn (can use chiral counting at low ǫ) ◮ A. Dobado et al. PRC2002 teaches us that mρ, mσ are

unaffected

300 400 500 600 700 800 900 1000 Re

✥ ✦✧ ✧ ✧ ✧ ✧ ✧ ✧ ✧ ✧

spole

★ ✩

M

MeV

★ ✪

250

200

150

100

50 m I

✫ ✬ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭

s

e l

  • p
✮ ✯ ✰ ✱ ✲

2

V e M

T

100 MeV T

200 MeV T

25 MeV T

100 MeV T

125 MeV Pole evolution with Temperature:

pole

pole

Low energy dynamics controlled by M, not Γ: T is not the most urgent concern.

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-65
SLIDE 65

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Effect of finite T?

◮ Mergers: temperatures of O(60) MeV ◮ At this level, T ∼ mπ ≪ mn (can use chiral counting at low ǫ) ◮ A. Dobado et al. PRC2002 teaches us that mρ, mσ are

unaffected

300 400 500 600 700 800 900 1000 Re

✵ ✶✷ ✷ ✷ ✷ ✷ ✷ ✷ ✷ ✷

spole

✸ ✹

M

MeV

✸ ✺

250

200

150

100

50 m I

✻ ✼ ✽ ✽ ✽ ✽ ✽ ✽ ✽ ✽ ✽

s

e l

  • p
✾ ✿ ❀ ❁ ❂

2

V e M

T

100 MeV T

200 MeV T

25 MeV T

100 MeV T

125 MeV Pole evolution with Temperature:

pole

pole

Low energy dynamics controlled by M, not Γ: T is not the most urgent concern.

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-66
SLIDE 66

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Interpolate between ρ grid points with Steffen’s method

A&A 239, 443-450 (1990). Plot by A. Windisch

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-67
SLIDE 67

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Are the EM and GW pulses from the same source?

(1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-68
SLIDE 68

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Are the EM and GW pulses from the same source?

There is about one γ-ray burst per day. What a coincidence in the sky... Distance to source: GW 40+8

−14 MPc

Electromagnetic 443

7 MPc

(associated galaxy)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-69
SLIDE 69

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Are the EM and GW pulses from the same source?

There is about one γ-ray burst per day. What a coincidence in the sky... Distance to source: GW 40+8

−14 MPc

Electromagnetic 443

7 MPc

(associated galaxy)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-70
SLIDE 70

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Tolman-Oppenheimer-Volkoff equation

General Relativistic Hydrostatic equilibrium (static, spherical body) dP dr = −GN r 2 (ε(r) + P(r))(M(r) + 4πr 3P(r)) 1 − 2GNM(r)

r

. + EOS + Mass: MGR = R⊙ 4πr 2ǫ(r)dr Compare with Newtonian Hydrostatic equilibrium dP = −GNM(r) r 2 dM dA Pressure profile

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-71
SLIDE 71

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Maximum mass for a given eq. of state

◮ Hydrostatic equilibrium:

pressure compensates weight of upper layers

◮ Causality limits the achievable pressure, c2 ≥ c2 s = dP dρ ◮ But nothing limits the amount of matter falling on the star ◮ ρ increases until P picks up ◮ When R∗ < RSchwarzschild = 2M∗, Gen. Rel. predicts collapse ◮ Within General Relativity, each EOS predicts a

maximum mass

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-72
SLIDE 72

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Maximum mass for a given eq. of state

◮ Hydrostatic equilibrium:

pressure compensates weight of upper layers

◮ Causality limits the achievable pressure, c2 ≥ c2 s = dP dρ ◮ But nothing limits the amount of matter falling on the star ◮ ρ increases until P picks up ◮ When R∗ < RSchwarzschild = 2M∗, Gen. Rel. predicts collapse ◮ Within General Relativity, each EOS predicts a

maximum mass

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-73
SLIDE 73

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Maximum mass for a given eq. of state

◮ Hydrostatic equilibrium:

pressure compensates weight of upper layers

◮ Causality limits the achievable pressure, c2 ≥ c2 s = dP dρ ◮ But nothing limits the amount of matter falling on the star ◮ ρ increases until P picks up ◮ When R∗ < RSchwarzschild = 2M∗, Gen. Rel. predicts collapse ◮ Within General Relativity, each EOS predicts a

maximum mass

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-74
SLIDE 74

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Maximum mass for a given eq. of state

◮ Hydrostatic equilibrium:

pressure compensates weight of upper layers

◮ Causality limits the achievable pressure, c2 ≥ c2 s = dP dρ ◮ But nothing limits the amount of matter falling on the star ◮ ρ increases until P picks up ◮ When R∗ < RSchwarzschild = 2M∗, Gen. Rel. predicts collapse ◮ Within General Relativity, each EOS predicts a

maximum mass

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-75
SLIDE 75

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Maximum mass for a given eq. of state

◮ Hydrostatic equilibrium:

pressure compensates weight of upper layers

◮ Causality limits the achievable pressure, c2 ≥ c2 s = dP dρ ◮ But nothing limits the amount of matter falling on the star ◮ ρ increases until P picks up ◮ When R∗ < RSchwarzschild = 2M∗, Gen. Rel. predicts collapse ◮ Within General Relativity, each EOS predicts a

maximum mass

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-76
SLIDE 76

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Measured pulsar masses before 2010

PRC77 065803 (2008)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-77
SLIDE 77

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Two-solar mass neutron star

Shapiro delay: allows for absolute measurement of the mass (Demorest et al. Nature 2010) ∆t = − log(1 − ˆ n1·ˆ n2)Rs c Confirmed with 2nd example (binary orbital data), Antoniadis et al. Science 340 1233232 (2013)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-78
SLIDE 78

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Bounds on the maximum

◮ All neutron stars have masses less than an (unknown)

EOS-dependent maximum

◮ The gravitational-wave event is claimed to bind that

maximum from above:

◮ Mmax < 2.17M⊙

1710.05938 from the radiation of the ejecta (not “red” enough) (a claim also in 1711.00314

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-79
SLIDE 79

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Bounds on the maximum

◮ All neutron stars have masses less than an (unknown)

EOS-dependent maximum

◮ The gravitational-wave event is claimed to bind that

maximum from above:

◮ Mmax < 2.17M⊙

1710.05938 from the radiation of the ejecta (not “red” enough) (a claim also in 1711.00314

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-80
SLIDE 80

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Bounds on the maximum

◮ All neutron stars have masses less than an (unknown)

EOS-dependent maximum

◮ The gravitational-wave event is claimed to bind that

maximum from above:

◮ Mmax < 2.17M⊙

1710.05938 from the radiation of the ejecta (not “red” enough) (a claim also in 1711.00314

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-81
SLIDE 81

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Used back then to exclude many models

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-82
SLIDE 82

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Static observables:

Bulk properties (very much like nuclear physics): M, R, I, Quadrupole moment Q, . . . , but also T, τcooling, Tidal deformability Qij = λEij Theory prediction of Q/J2 quadrupole moment for three equations of state

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-83
SLIDE 83

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

M(R) quite vertical for 1.4M⊙: a measurement fixes EOS

The three EOS of Hebeler et al. (Schwenk), APJ 773 11 (2013)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-84
SLIDE 84

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Radii from quiescent X-ray sources

(Picture from Ben Williams, UW)

  • 1. X-ray spectrum =

⇒ temperature T

  • 2. Lapparentd2 = LR2
  • 3. Luminosity to size

L = σ(πR2)T 4 R = 9.4 ± 1.2km

Guillot and Rutledge APJ796,1 (2014).

Typical radii calculated with GR: R ≃ 11 − 13km

New light U-boson exchange? (1509.02128)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-85
SLIDE 85

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Other attempts to measure radii

Problems:

◮ Atmosphere of star and interstellar gas absorb X-rays ◮ Bad thermal spectrum

Try methods with different systematics

◮ Thermonuclear burst sources R = (10.4 − 12.9)km ◮ Gravitational radiation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-86
SLIDE 86

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Other attempts to measure radii

Problems:

◮ Atmosphere of star and interstellar gas absorb X-rays ◮ Bad thermal spectrum

Try methods with different systematics

◮ Thermonuclear burst sources R = (10.4 − 12.9)km ◮ Gravitational radiation

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-87
SLIDE 87

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Where is the radius in a Gravitational Waveform?

After merger: Numerical relativity + EOS = ⇒ Maximum frequency reads off the radius Hoaw fast can you spin a bar?

Kaneyama et al. PRD93, 123010 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-88
SLIDE 88

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Where is the radius in a Gravitational Waveform?

After merger: Numerical relativity + EOS = ⇒ Maximum frequency reads off the radius Hoaw fast can you spin a bar?

Kaneyama et al. PRD93, 123010 (2016)

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-89
SLIDE 89

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Simulations = ⇒ Tidal deformability λ = ⇒ R

δR/0.91km R/13km = δλ/400 λ/1000 Extraction comparing simulated gravitational waveforms h1 and h2

Hotokezaka et al., PRD93, 064082 (2016) for M = 1.35M⊙

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-90
SLIDE 90

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Frequency maximum would closely track tidal deformability

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-91
SLIDE 91

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Frequency maximum would closely track tidal deformability

Rezzolla and Takami, 1604.00246

  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-92
SLIDE 92

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Other effects: waves in flat space

(Tight bounds because tpropagation tgeneration ∼ Distance Source mass

◮ Scalar (third) polarization h =

h0 + h+ hx −hx h0 − h+

  • ◮ Depending on the sign of a in aR2
  • 1. Dispersion relation with a mass m2

R = 1+f′R(0) 3f′′R(0)

(Ligo already constrains it to mR < 10−22eV see P. Bicudo, 1602.04337)

  • 2. superluminal speed (actually it is space contracting)
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars

slide-93
SLIDE 93

Neutron star mergers are a testbed for General Relativity Hadron physics input (this talk: Eq. of State) Providing an EoS with minimum bias Do not assume GR: a software implementation

Other effects: waves in flat space

(Tight bounds because tpropagation tgeneration ∼ Distance Source mass

◮ Scalar (third) polarization h =

h0 + h+ hx −hx h0 − h+

  • ◮ Depending on the sign of a in aR2
  • 1. Dispersion relation with a mass m2

R = 1+f′R(0) 3f′′R(0)

(Ligo already constrains it to mR < 10−22eV see P. Bicudo, 1602.04337)

  • 2. superluminal speed (actually it is space contracting)
  • F. J. Llanes-Estrada

Equation of State for modified gravity studies at neutron stars