Cosmological tests of ultra-light axions

Transcription

1 Cosmological tests of ultra-light axions Daniel Grin University of Chicago IAU General Assembly, Honolulu, 8/11/2015 FM5 The legacy of Planck R.Hlozek, DG, D.J. E. Marsh, P.Ferreira, arxiv: , PRD 91,

2 Cosmological tests of ultra-light axions Daniel Grin University of Chicago IAU General Assembly, Honolulu, 8/11/2015 FM5 The legacy of Planck R.Hlozek, DG, D.J. E. Marsh, P.Ferreira, arxiv: , PRD 91,

3 What are axions? New scalar field with global U(1) symmetry! L CPV = g G G a f a g 2 G G a ' 1 ' 2 Couples to SM gauge fields (via fermions) Dynamically erases QCD CP-violation Mass from QCD instantons Peccei + Quinn (1977), Weinberg +Wilczek (1978), Kim (1979), Shifman et. al (1980), Zhitnitsky (1980), Dine et al. (1981), Sikivie (1983),D.B. Kaplan (1985), A.E Nelson (1985,1990) 2

4 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds 3

5 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Hundreds of scalars with approx shift symmetry 3

6 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Hundreds of scalars with approx shift symmetry Many axions 3

7 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Hundreds of scalars with approx shift symmetry Many axions Mass acquired non-perturbatively (instantons, D-Branes) m 2 a = µ4 f 2 a e Volume 3

8 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Hundreds of scalars with approx shift symmetry Mass acquired non-perturbatively (instantons, D-Branes) Scale of new ultra-violet physics m 2 a = µ4 f 2 a e Volume Many axions 3

9 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Hundreds of scalars with approx shift symmetry Many axions Mass acquired non-perturbatively (instantons, D-Branes) Scale of extra dimensions in Planck units m 2 a = µ4 fa 2 e Volume 3

10 Ultra-light axions (ULAS) in string theory In string theory, extra dimensions compactified: Calabi-Yau manifolds ' 1 ' 2 +. Axiverse! Arvanitaki Witten and Srvcek (2006), Acharya et al. (2010), Cicoli (2012) ' 1 ' 2 '1 ' 2 3

11 Cosmology of ultra-light axions: dark matter and dark energy candidates 10 0 Matter ULAs Density Scale of universe~ (1 + z)

12 Cosmology of ultra-light axions: dark matter and dark energy candidates 10 0 Matter ULAs Density 10 5 m a 3H -like behavior Scale of universe~ (1 + z)

13 Cosmology of ultra-light axions: dark matter and dark energy candidates 10 0 Matter ULAs Density m a 3H matter-like behavior Scale of universe~ (1 + z)

14 Cosmology of ultra-light axions: dark matter and dark energy candidates Scale corresponding to typical galaxy separation today Causal horizon Frieman et al 1995, Coble et al ULA as dark energy with specific w(z) m a ev ULA matter behavior starts too late for struct. formation 4

15 Cosmology of ultra-light axions: dark matter and dark energy candidates Scale corresponding to typical galaxy separation today Causal horizon Frieman et al 1995, Coble et al ULA as dark matter m a & ev ULA matter behavior starts in time for struct. formation 4

16 Cosmology of ultra-light axions: dark matter and dark energy candidates Scale corresponding to typical galaxy separation today Frieman et al 1995, Coble et al Causal horizon Corresponds to time of matter/radiation equality, when m = + 4

17 Cosmology of ultra-light axions: dark matter and dark energy candidates Scale corresponding to typical galaxy separation today Frieman et al 1995, Coble et al Causal horizon Simple relic density constraints: 4

18 What about ultra-light axions (ULAs)? Photon couplings are model-dependent: Use gravity and cosmological data to test ULAs 5

19 AxiCAMB CMB and matter perturbation code including ULAs! Code in prep for public release as part of CosmoSIS package Included in H recombination Expansion history AXIONS! Einstein equations NR fluid eqs. dark matter gravitational perturbations neutrinos NR fluid eqs. baryons photons Boltzmann hierarchy Thomson scattering 6 ULA of any mass is self-consistently followed from DE to DM regime 6

20 Growth Effective fluid of ula formalism perturbations for ULA DM Perturbed Klein-Gordon + Gravity Axionic Jeans Scale is macroscopic [in contrast to QCD axion]: J =2.5 Mpc Axion debroglie wavelength m 1/2 a h 1/ ev Macroscopic length scale

21 Growth Effective fluid of ula formalism perturbations for ULA DM Perturbed Klein-Gordon + Gravity Axionic Jeans Scale is macroscopic [in contrast to QCD axion]: Computing observables is expensive m a for 1/2 m a 3H: J =2.5 Mpc m h 1/2 a 3H ev Coherent oscillation requires prohibitive time step WKB approximation at late time, exact KG early times c 2 a = P a a = k 2 /m 2 a 4/(1 + z) 2 + k 2 /m 2 a 7

22 Growth Effective fluid of ula formalism perturbations for ULA DM ULA DM CDM Pressure stabilization for modes with k k J p mh Otherwise ULAs behave like cold dark matter (CDM) 8

23 ULAs as dark energy and the angular sound horizon D (sensitivetoanyenergysource) r s Atomic physics Sound horizon = r s D Fig. modified from T. Smith with permission 9 9 9

24 ULAs as dark energy and the angular sound horizon D (sensitivetoanyenergysource) ) ' 1.5 r s Atomic physics Sound horizon = r s D Fig. modified from T. Smith with permission 9 9 9

25 ULAs as dark energy and the angular sound horizon D(z decoupling ) D axion (zdecoupling axion ) D(z decoupling ) 9 9

26 ULAs as dark energy and the angular sound horizon `(` + 1)C ` TT /2 [µk 2 ] =0.68 ( a / d! 0) a / d =0.1, m a = ev a / d =0.25, m a = ev a / d =0.5, m a = ev a / d =0.66, m a = ev Planck Multipole ` 9 9

27 ULAs as dark energy and the angular sound horizon `(` + 1)C ` TT /2 [µk 2 ] H 0 = ( a / d! 0) a / d =0.1, m a = ev a / d =0.25, m a = ev a / d =0.25, m a = ev s a / d =0.1, m a = ev Planck d A / r 1 s d A (z =1100) = l peak CMB Z dz H(z) Absorb and lock onto usual peaks by lowering H Multipole ` 9 9

28 ULAs as dark energy and perturbations in other fluids Low mass (DE-like) case: late Integrated Sachs-Wolfe Effect CMB temperature anisotropies from potential decay 10 10

29 ULAs as dark energy and perturbations in other fluids Low mass (DE-like) case: late Integrated Sachs-Wolfe Effect CMB temperature anisotropies from potential decay 10 10

30 ULAs as dark energy and perturbations in other fluids Low mass (DE-like) case: late Integrated Sachs-Wolfe Effect CMB temperature anisotropies from potential decay 10 10

31 ULAs and the CMB: high mass and early ISW Higher mass (DM-like) case: high-l ISW CMB temperature anisotropies from potential decay 11 11

32 ULAs and the CMB: high mass and early ISW Higher mass (DM-like) case: high-l ISW CMB temperature anisotropies from potential decay 11 11

33 ULAs and the CMB: high mass and early ISW Higher mass (DM-like) case: high-l ISW Radiation pressure causes potential decay 11 11

34 ULAs and the CMB: high mass and early ISW Higher mass (DM-like) case: high-l ISW 11 11

35 Matter power spectrum for ULA (in DM regime) DM perturbation growth severely suppressed if Suppression grows with Analogous to effect of neutrinos 12

36 Matter power spectrum for ULA (in DM regime) Suppression grows with Analogous to effect of neutrinos 12

37 Data Planck 2013 temperature anisotropy power spectra (+SPT+ACT) Cosmic variance limited to WiggleZ galaxy survey (linear scales only ) 240,000 emission line galaxies at z<1 3.9 m Anglo-Australian Telescope (AAT) 13

38 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion 14

39 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion ULA parameters 14

40 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion Densities of standard species 14

41 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion ns 1 2 k R(k) A s k 0 Initial conditions 14

42 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion reion = Z dln e T 14

43 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion AxiCAMB Compare with data Explore posterior using Monte Carlo Markov Chain (MCMC) 14

44 Difficult parameter space m a, a h 2, c h 2, b h 2,,n s,a s, reion Addressed using nested sampling MULTINEST (Hobson, Feroz, others 2008) 14

45 CONSTRAINTS a a + c Allowed Allowed Interesting constraints over 7 orders of magnitude in mass: Thanks to AXICAMB and MULTINEST ULAs highly constrained if ULAs are viable DM/DE candidates in linear theory outside ``belly 15

46 ONGOING WORK: CMB LENSING A slice of (dark matter) life at z~1 16

47 ONGOING WORK: CMB LENSING ULA saturating TT-only limits falsifiable at 4.5σ Planck 2015 Lensing L 2 ULAs change lens geometry and growth of structure 16

48 ongoing work: preparing AxiCamb for public release CosmoSIS (Zuntz + others) allows Modular use of power-spectrum codes and data sets (e.g. CMB lensing, galaxy lensing, etc..) Clever samplers We are packaging AxiCAMB in a wrapper to allow use in CosmoSIS Added self-consistent treatment of K and m 17

49 AXIONS AND ISOCURVATURE FLUCTUATIONS 18

50 AXIONS AND ISOCURVATURE FLUCTUATIONS If f a >H I Quantum'fluctua*ons De Sitter expansion imprints scale invariant fluctuations = = some schematics from Wands, Enqvist, Lyth, Takahashi ( ) p ha2 i = H I 2 horiz Quantum zero-point fluctuations! a tot! a 10 5 S a = n a n a n n = a 3 a

51 AXIONS AND ISOCURVATURE FLUCTUATIONS If f a >H I Quantum'fluctua*ons De Sitter expansion imprints scale invariant fluctuations = = some schematics from Wands, Enqvist, Lyth, Takahashi ( ) horiz 18

52 AXIONS AND ISOCURVATURE FLUCTUATIONS If f a >H I Quantum'fluctua*ons De Sitter expansion imprints scale invariant fluctuations = = some schematics from Wands, Enqvist, Lyth, Takahashi ( ) horiz Adiabatic fluctuations 18

53 ULAS AND ISOCURVATURE FLUCTUATIONS 10 4 `(` + 1)C`/2p [µ K 2 ] =(0.01) 2 Cutoff from macroscopic Jeans Scale increasing m a Multipole ` Isocurvature spectra have distinct phase structure from adiabatic fluctuations Spectra from AXICAMB using initial conditions obtained in DG+ (2015 in prep) 19

54 ULAS AND ISOCURVATURE FLUCTUATIONS Planck 2013 TT Angular scale D [µk 2 ] Multipole moment, 19

55 ULAS AND ISOCURVATURE FLUCTUATIONS QCD axion GeV 7/2 ULAs GeV H I H I D.J.E. Marsh, DG, R. Hlozek, P.Ferreira: arxiv: , Phys. Rev. Lett. 113, arxiv: , Phys. Rev. D 87, (R) Also see Gondolo and Visinelli 2012,

56 FORECAST/FUTURE WORK: TENSORS AND ULAS Primordial gravitational waves are sensitive to H I Potentially observable CMB polarization signature B-mode Current limits are QCD axion H I GeV. If saturated by a detection: ULA 20

57 FORECAST/FUTURE WORK: TENSORS AND ULAS Primordial gravitational waves are sensitive to H I Potentially observable CMB polarization signature B-mode Warning! Polarized foregrounds are challenging [e.g. BICEP2+Planck 2015] 20

58 FORECAST/FUTURE WORK: TENSORS AND ULAS Primordial gravitational waves are sensitive to H I Potentially observable CMB polarization signature B-mode Future CMB experiments may tell us more SPT/BICEP2-3/KECK Spider CORE 20

59 CONCLUSIONS AND TAKE-AWAY Ultra-light axions may be probed at the 0.5% level using current cosmological data CMB weak lensing, entropy fluctuations, and gravitational waves are a powerful ULA probe Planck 2015 likelihood now public [including polarization] analysis underway Public AxiCAMB will be available later this summer 21