Looking for axions with astrophysical black holes Sergei Dubovsky - - PowerPoint PPT Presentation

Looking for axions with astrophysical black holes

Sergei Dubovsky

CCPP (NYU)

dark Solvay Workshop “The side of black holes”

Looking for axions with astrophysical black holes

Sergei Dubovsky

CCPP (NYU)

Solvay Workshop “The side of black holes” bright

Plan of the Talk

✦Brief overview of superradiance ✦Brief overview of axions ✦Superradiance and supermassive black hole nurturing ✦Superradiance and local phase transitions see a talk by Pani for an up to date detailed story

Generic superradiance: rotating absorbing

• bject may serve as a source of energy

Super-radiant scattering of a massive object

Zeldovich’71

Generic superradiance: rotating absorbing

• bject may serve as a source of energy

Super-radiant scattering of a massive object

Zeldovich’71

Generic superradiance: rotating absorbing

• bject may serve as a source of energy

Super-radiant scattering of a massive object Super-radiant scattering of a wave

Zeldovich’71

Generic superradiance: rotating absorbing

• bject may serve as a source of energy

Super-radiant scattering of a massive object Super-radiant scattering of a wave

Zeldovich’71

Penrose Process

Ergoregion Rotating Black Hole Penrose’69; Misner'72; Starobinsky’73

Penrose Process

Extracts angular momentum and mass from a spinning black hole

Ergoregion Rotating Black Hole Penrose’69; Misner'72; Starobinsky’73

Black Hole Bomb

Photons reflected back and forth from the black hole and through the ergoregion

Press & Teukolsky 1972

Black Hole Bomb

Photons reflected back and forth from the black hole and through the ergoregion

Press & Teukolsky 1972

Superradiance for a massive boson

Particle Compton wavelength comparable to the size of a black hole

Damour et al.’76; Gaina et al.’78; Detweiler’80; Zouros & Eardley’79; Press & Teukolsky’72

m ∼ 10−10 ÷ 10−20 eV

Superradiance for a massive boson

Particle Compton wavelength comparable to the size of a black hole

Damour et al.’76; Gaina et al.’78; Detweiler’80; Zouros & Eardley’79; Press & Teukolsky’72

m ∼ 10−10 ÷ 10−20 eV

Superradiance for a massive boson

Particle Compton wavelength comparable to the size of a black hole

Damour et al.’76; Gaina et al.’78; Detweiler’80; Zouros & Eardley’79; Press & Teukolsky’72

m ∼ 10−10 ÷ 10−20 eV

Standard Model Landscape

Arkani-Hamed, SD, Nicolis, Villadoro hep-th/0703067

What are the vacua in the Standard Model?

Radion Potential

R

V (R) classical contribution from Λ Casimir from g, γ

Rmax = 14 µm ∼ Λ−1/4

Casimir from

νe,µ,τ

R0 ∼ (2πmν)−1

lAdS ≈ 3.7 · 1027cm 2πR0 ≈ 20µm AdS3 × S1

vacuum with

Trichamoeba sp.

typical habitant of the SM Landscape 50µm

Extremal Reissner-Nordstrom black holes connect between flat and vacua AdS2 × S2

ds2 = (1 − rh r )2dt2 − dr2 (1 − rh

r )2 − r2dΩ2 2

Many More Vacua

Particles in vacuum

AdS3 × S1

✦All of the Standard Model ✦Radion (a cousin of graviton) with

mR ∼ R−2 MP l ∼ 10−40GeV

✦Axion (a cousin of photon/Aharonov-Bohm flux) with

ma ∼ eR−2

0 e−2πR0me ∼ e−108

f 2

a ∼

1 2πR0e2

Exponentially light axion comes from power-like small fa

String Lanscape:

Plenitude (‘ ‘) of vacua

∼ 10500

Ultimate Unification of Fundamental Physics and Geography

Standard Model Hidden Valley I Hidden Valley II

In both cases no reasons to apply Occam’s razor

Axions in String Theory

Exactly the same story! Starting from a higher dimensional theory, and very small and very complicated internal compact manifold

µa ∝ e−

MP l fa

suggests

MP l fa ∼ 100

the same factor is suggested by gauge coupling unification

The QCD axion

Sa = ⇤ d4x 1 2(⇤µa)2 + a 32⇥2fa µνλρTr GµνGλρ ⇥

θeff ⇥a(x)⇤ fa + ¯ θ = 0

solves strong CP!

Non-pert QCD gives potential of height

Λ4

QCD = µ4 exp(−8π/αs(µ))

Axion is a pseudo-Nambu-Goldstone boson

ma ∼ Λ2

QCD

fa ∼ 6 × 10−10eV 1016GeV fa ⇥

Minimum of potential leads to axion vev such that

V (a)

= ⇒

Gravitational Atom in the Sky

Occupation number Far from the Black Hole: Newtonian Potential fermions − → bosons 1 − → 1075 αEM = e2 4π − → α = GNMBHµa = Rgµa Ebinding = −α2

EMme

2n2 − → Ebinding = −α2µa 2n2

Arvanitaki, Dimopoulos, SD, Kaloper, March-Russel 0904.4720 Arvanitaki, SD 1004.3558

0.5 1.0 1.5 2.0 2.5 10-16 10-14 10-12 10-10 10-8 10-6 m aâ Rg Super -radiance Rate in units of Rg

• 1

0.0 0.1 0.2 0.3 0.4 0.5 10-16 10-14 10-12 10-10 10-8 10-6 m aâ Rg Super -radiance Rate in units of Rg

• 1

0.0 0.1 0.2 0.3 0.4 0.5 10-16 10-14 10-12 10-10 10-8 10-6 m aâ Rg Super -radiance Rate in units of Rg

• 1

l=1 l=2 l=3 l=5

a=1 a=0.9 a=0.8 a=0.7

Superradiance Parametrics

a : BH spin, between 0 and 1 ωaxion < m Ω+ Superradiance Condition µa + Ebinding < m a 2Rg(1 + √ 1 − a2) m : magnetic quantum number Maximum superradiance rate for level with min. l, max. m

l=4

Axion annihilations

BH Gravitational field ωgraviton = 2 maxion

Graviton Transitions

Super-Radiant Mode (n+1, l, m) Super-Radiant Mode (n, l, m) Gravitons

Spin Gap for the QCD Axion

ma=2x10-11eV, fa=3x1017GeV 5 10 15 20 0.0 0.2 0.4 0.6 0.8 1.0 Black Hole Mass HMüL Black Hole Spin a

Arvanitaki, Baryakhtar, Huang 1411.2263

QCD axion

2s exclusion

1 2 3 5 4 5: GRS 1915+105 4: Cyg X-1 3: GRO J1655-40 2: LMC X-1 1: M33 X-7

• 13
• 12
• 11
• 10
• 9
• 20
• 18
• 16
• 14
• 12
• Log@maêeVD

Log@GeVê faD

Combined Exclusion Plot

Arvanitaki, Baryakhtar, Huang 1411.2263

QCD axion

2s exclusion

1 2 3 5 4 5: GRS 1915+105 4: Cyg X-1 3: GRO J1655-40 2: LMC X-1 1: M33 X-7

• 13
• 12
• 11
• 10
• 9
• 20
• 18
• 16
• 14
• 12
• Log@maêeVD

Log@GeVê faD

Combined Exclusion Plot

“easy” Planckian QCD axion “hard” GUT QCD axion

Expected Events from Annihilations

Large uncertainties coming from tails of BH mass distribution

ANNIHILATIONS

tcoh=2 days ttot= 1 year

Explorer Voyager aLIGO Design aLIGO 2015

10-13 10-12 10-11 10-10 0.01 1 100 104 100 100 1000 1000 10000 ma HeVL Expected Events f HHzL

Expected detectable sources

Pessimistic: flat spin distribution and 0.1 BH/century Realistic: 30% above spin of 0.8 and 0.4 BH/century Optimistic: 90% above spin of 0.9 and 0.9 BH/century

Arvanitaki, Baryakhtar, Dimopoulos, SD, Lasenby 1604.03958

GUT QCD axion

✦ Running out of BHs. l>1, large regime ✦Spindown and annihilations signals are too small ✦Most conservative from theory viewpoint ✦Need to think how to go for high frequencies ✦Need to understand axion non-linearities. Bosenova burst? ✦Need to look for possible ways to transmit GW power into lower frequencies: ✦6g-5g transitions? ✦ Resonances in binary systems?

α

Baumann, Sheng Chia, Porto 1804.03208 Arvanitaki, Geraci 1207.5320

ma=2x10-11eV, fa=3x1017GeV 5 10 15 20 0.0 0.2 0.4 0.6 0.8 1.0 Black Hole Mass HMüL Black Hole Spin a

GUT QCD axion

✦ Running out of BHs. l>1, large regime ✦Spindown and annihilations signals are too small ✦Most conservative from theory viewpoint ✦Need to think how to go for high frequencies ✦Need to understand axion non-linearities. Bosenova burst? ✦Need to look for possible ways to transmit GW power into lower frequencies: ✦6g-5g transitions? ✦ Resonances in binary systems?

α

Baumann, Sheng Chia, Porto 1804.03208 Arvanitaki, Geraci 1207.5320

Transition Events Estimates

• Lower number of observable sources due to signal duration

Expected detectable sources

TRANSITIONS

tcoh=2 days ttot= 1 year Explorer Voyager aLIGO Design aLIGO 2015

1¥10-12 2¥10-12 5¥10-12 1¥10-11 2¥10-11 5¥10-11 1¥10-10 0.001 0.01 0.1 1 10 10 10 100 100 ma HeVL Expected Events f HHzL for a=1.25 and 6g5g

T = 1.×1010yrs; M = 10 M☉

⟵ Γ211

SR<T-1

⟵ Γ322

SR<T-1

⟵ Γ322

SR<200T-1

⟶ Multiple levels 211 growth affected ^

θ∼10-2 θ∼10-2 θ∼.05 θ∼10-3 θ∼10-4 δωλ ωgr ∼10-6 δωλ ωgr ∼10-4 δωλ ωgr ∼10-2

211 depleted before 322 grows GWs stop 322 growth ⟵ No 322 fa growth 1 2 3 4

1.×10-13 5.×10-13 1.×10-12 5.×10-12 1.×10-11 1 10 100 1000 104 105 106 μ (eV) Mpl/fa

Transition Events Estimates Non-linear dynamics is hard…

Baryakhtar, Galanis, Lasenby, Simon in progress

Remaining 10 orders of magnitude in masses: Many ways to be inventive!

Effects on BH accretion rate Axion spins BH down and accelerates the accretion rate

0.5 1.0 1.5 2.0 2.5 3.0 3.5 104 105 106 107 108 109 1010 Time in units of ΤEddington Black Hole Mass in units of MSolar

Arvanitaki, SD 1004.3558

dM dt = 1 − ✏M(¯ a) ✏M(¯ a) M ⌧E + ˙ Msr

Superradiant Creates Huge Field Values Setup:

✦Axion, coupled to QCD-like sector.

At least 3 light quark flavors with close masses. Pure glue also works.

L = F 2

π

4 Tr ∂U †∂U + Λ3 2 Tr

• Me−iθ/NU + Meiθ/NU †

Effective action describing axion and mesons:

✦Some portal, allowing for hidden pions to annihilate

into SM. Simplest example: dark photon with kinetic mixing.

SD, Gorbenko, 1012.2893

Maxima Saddle Points Minima

a) b) θ θc V θ θc V

. .

Figure 1: Extrema of the axion potential at N = 3 for equal quark masses (left), and for mass ratios 1:1.2:1.4 (right).

Axion Monodromy

Figure 2: A total energy release as a function of a characteristic temperature of a fireball for different values of parameters ↵ and l. Two red axes on top represent a corresponding black hole mass and time scale for ↵ = 0.5, l = 1. For the blue line a black hole mass is 5 times larger than the value on the red axis and a time scale is 5 times longer. For the green line a black hole is 5 times lighter and a time scale is ∼ 51/3 times longer.

What about QCD itself?

What happens to nuclear physics at large ?

θ

Conclusions

✦Superradiance opens lots of opportunities to

brighten up black holes

✦Lots of analytical and numerical work still needs

to be done to fully understand this phenomenon and to make a full use of these opportunities