Low- CMB power loss in string inflation

  • Francisco G. PedroEmail author
  • Alexander Westphal
Open Access


A lack of power on large scales ( ≲ 40) might have been observed by the PLANCK satellite. We argue that this putative feature can be explained by a phase of fast roll at the onset of inflation. We show that in the context of single field models what is required is an asymmetric inflection point model of which fibre inflation is a string motivated example. We study the ability of fibre inflation to generate a suppression of the CMB 2-point function power at low , finding that the potential derived from string loops is not steep enough for this purpose. We introduce a steeper contribution to the potential, that dominates away from the inflationary region, and show that if properly tuned it can indeed lead to a spectrum with lack of power at large scales.


Strings and branes phenomenology 


Open Access

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  1. [1]
    HST collaboration, W. Freedman et al., Final results from the Hubble Space Telescope key project to measure the Hubble constant, Astrophys. J. 553 (2001) 47 [astro-ph/0012376] [INSPIRE].ADSCrossRefGoogle Scholar
  2. [2]
    A.G. Riess et al., A 3% solution: determination of the Hubble constant with the Hubble Space Telescope and Wide Field Camera 3, Astrophys. J. 730 (2011) 119 [Erratum ibid. 732 (2011) 129] [arXiv:1103.2976] [INSPIRE].
  3. [3]
    Supernova Search Team collaboration, A.G. Riess et al., Observational evidence from supernovae for an accelerating universe and a cosmological constant, Astron. J. 116 (1998) 1009 [astro-ph/9805201] [INSPIRE].ADSCrossRefGoogle Scholar
  4. [4]
    Supernova Cosmology Project collaboration, S. Perlmutter et al., Measurements of Ω and Λ from 42 high redshift supernovae, Astrophys. J. 517 (1999) 565 [astro-ph/9812133] [INSPIRE].ADSCrossRefGoogle Scholar
  5. [5]
    WMAP collaboration, G. Hinshaw et al., Nine-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: cosmological parameter results, Astrophys. J. Suppl. 208 (2013) 19 [arXiv:1212.5226] [INSPIRE].ADSCrossRefGoogle Scholar
  6. [6]
    Planck collaboration, P. Ade et al., Planck 2013 results. XVI. Cosmological parameters, arXiv:1303.5076 [INSPIRE].
  7. [7]
    Planck collaboration, P. Ade et al., Planck 2013 results. XXII. Constraints on inflation, arXiv:1303.5082 [INSPIRE].
  8. [8]
    Atacama Cosmology Telescope collaboration, J.L. Sievers et al., The Atacama Cosmology Telescope: cosmological parameters from three seasons of data, JCAP 10 (2013) 060 [arXiv:1301.0824] [INSPIRE].ADSCrossRefGoogle Scholar
  9. [9]
    K. Story, C. Reichardt, Z. Hou, R. Keisler, K. Aird et al., A measurement of the cosmic microwave background damping tail from the 2500-square-degree SPT-SZ survey, Astrophys. J. 779 (2013) 86 [arXiv:1210.7231] [INSPIRE].ADSCrossRefGoogle Scholar
  10. [10]
    Z. Hou, C. Reichardt, K. Story, B. Follin, R. Keisler et al., Constraints on cosmology from the cosmic microwave background power spectrum of the 2500-square degree SPT-SZ Survey, Astrophys. J. 782 (2014) 74 [arXiv:1212.6267] [INSPIRE].ADSCrossRefGoogle Scholar
  11. [11]
    D. Baumann, TASI lectures on inflation, arXiv:0907.5424 [INSPIRE].
  12. [12]
    Planck collaboration, P. Ade et al., Planck 2013 results. XXIV. Constraints on primordial non-Gaussianity, arXiv:1303.5084 [INSPIRE].
  13. [13]
    Planck collaboration, P. Ade et al., Planck 2013 results. XV. CMB power spectra and likelihood, arXiv:1303.5075 [INSPIRE].
  14. [14]
    Planck collaboration, P. Ade et al., Planck 2013 results. XXIII. Isotropy and statistics of the CMB, arXiv:1303.5083 [INSPIRE].
  15. [15]
    R. Bousso, D. Harlow and L. Senatore, Inflation after false vacuum decay: observational prospects after Planck, arXiv:1309.4060 [INSPIRE].
  16. [16]
    A.D. Linde, A toy model for open inflation, Phys. Rev. D 59 (1999) 023503 [hep-ph/9807493] [INSPIRE].ADSMathSciNetGoogle Scholar
  17. [17]
    A.D. Linde, M. Sasaki and T. Tanaka, CMB in open inflation, Phys. Rev. D 59 (1999) 123522 [astro-ph/9901135] [INSPIRE].ADSGoogle Scholar
  18. [18]
    D. Yamauchi, A. Linde, A. Naruko, M. Sasaki and T. Tanaka, Open inflation in the landscape, Phys. Rev. D 84 (2011) 043513 [arXiv:1105.2674] [INSPIRE].ADSGoogle Scholar
  19. [19]
    S.R. Coleman, The fate of the false vacuum. 1. Semiclassical theory, Phys. Rev. D 15 (1977) 2929 [Erratum ibid. D 16 (1977) 1248] [INSPIRE].
  20. [20]
    S.R. Coleman and F. De Luccia, Gravitational effects on and of vacuum decay, Phys. Rev. D 21 (1980) 3305 [INSPIRE].ADSGoogle Scholar
  21. [21]
    C.R. Contaldi, M. Peloso, L. Kofman and A.D. Linde, Suppressing the lower multipoles in the CMB anisotropies, JCAP 07 (2003) 002 [astro-ph/0303636] [INSPIRE].ADSCrossRefGoogle Scholar
  22. [22]
    J.F. Donoghue, K. Dutta and A. Ross, Non-isotropy in the CMB power spectrum in single field inflation, Phys. Rev. D 80 (2009) 023526 [astro-ph/0703455] [INSPIRE].ADSGoogle Scholar
  23. [23]
    E. Dudas, N. Kitazawa, S. Patil and A. Sagnotti, CMB imprints of a pre-inflationary climbing phase, JCAP 05 (2012) 012 [arXiv:1202.6630] [INSPIRE].ADSCrossRefGoogle Scholar
  24. [24]
    A. Sagnotti, Brane SUSY breaking and inflation: implications for scalar fields and CMB distortion, arXiv:1303.6685 [INSPIRE].
  25. [25]
    T. Biswas and A. Mazumdar, Super-inflation, non-singular bounce and low multipoles, Class. Quant. Grav. 31 (2014) 025019 [arXiv:1304.3648] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  26. [26]
    S. Kachru, R. Kallosh, A.D. Linde and S.P. Trivedi, De Sitter vacua in string theory, Phys. Rev. D 68 (2003) 046005 [hep-th/0301240] [INSPIRE].ADSMathSciNetGoogle Scholar
  27. [27]
    L. Susskind, The anthropic landscape of string theory, hep-th/0302219 [INSPIRE].
  28. [28]
    M. Graña, Flux compactifications in string theory: a comprehensive review, Phys. Rept. 423 (2006) 91 [hep-th/0509003] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    M.R. Douglas and S. Kachru, Flux compactification, Rev. Mod. Phys. 79 (2007) 733 [hep-th/0610102] [INSPIRE].ADSCrossRefzbMATHMathSciNetGoogle Scholar
  30. [30]
    D. Baumann and L. McAllister, Advances in inflation in string theory, Ann. Rev. Nucl. Part. Sci. 59 (2009) 67 [arXiv:0901.0265] [INSPIRE].ADSCrossRefGoogle Scholar
  31. [31]
    M. Cicoli and F. Quevedo, String moduli inflation: an overview, Class. Quant. Grav. 28 (2011) 204001 [arXiv:1108.2659] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  32. [32]
    C. Burgess, M. Cicoli and F. Quevedo, String inflation after Planck 2013, JCAP 11 (2013) 003 [arXiv:1306.3512] [INSPIRE].ADSCrossRefGoogle Scholar
  33. [33]
    M. Cicoli, C. Burgess and F. Quevedo, Fibre inflation: observable gravity waves from IIB string compactifications, JCAP 03 (2009) 013 [arXiv:0808.0691] [INSPIRE].ADSCrossRefGoogle Scholar
  34. [34]
    V. Balasubramanian, P. Berglund, J.P. Conlon and F. Quevedo, Systematics of moduli stabilisation in Calabi-Yau flux compactifications, JHEP 03 (2005) 007 [hep-th/0502058] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  35. [35]
    J.P. Conlon, F. Quevedo and K. Suruliz, Large-volume flux compactifications: moduli spectrum and D3/D7 soft supersymmetry breaking, JHEP 08 (2005) 007 [hep-th/0505076] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  36. [36]
    M. Cicoli, J.P. Conlon and F. Quevedo, Systematics of string loop corrections in type IIB Calabi-Yau flux compactifications, JHEP 01 (2008) 052 [arXiv:0708.1873] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  37. [37]
    D. Baumann, A. Dymarsky, I.R. Klebanov and L. McAllister, Towards an explicit model of D-brane inflation, JCAP 01 (2008) 024 [arXiv:0706.0360] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  38. [38]
    R.K. Jain, P. Chingangbam, J.-O. Gong, L. Sriramkumar and T. Souradeep, Punctuated inflation and the low CMB multipoles, JCAP 01 (2009) 009 [arXiv:0809.3915] [INSPIRE].ADSCrossRefGoogle Scholar
  39. [39]
    R.K. Jain, P. Chingangbam, L. Sriramkumar and T. Souradeep, The tensor-to-scalar ratio in punctuated inflation, Phys. Rev. D 82 (2010) 023509 [arXiv:0904.2518] [INSPIRE].ADSGoogle Scholar
  40. [40]
    S. Downes and B. Dutta, Inflection points and the power spectrum, Phys. Rev. D 87 (2013) 083518 [arXiv:1211.1707] [INSPIRE].ADSGoogle Scholar
  41. [41]
    M. Cicoli, F.G. Pedro and G. Tasinato, Poly-instanton inflation, JCAP 12 (2011) 022 [arXiv:1110.6182] [INSPIRE].ADSCrossRefGoogle Scholar
  42. [42]
    M. Berg, M. Haack and B. Körs, String loop corrections to Kähler potentials in orientifolds, JHEP 11 (2005) 030 [hep-th/0508043] [INSPIRE].ADSCrossRefGoogle Scholar
  43. [43]
    G. von Gersdorff and A. Hebecker, Kähler corrections for the volume modulus of flux compactifications, Phys. Lett. B 624 (2005) 270 [hep-th/0507131] [INSPIRE].ADSCrossRefGoogle Scholar
  44. [44]
    M. Cicoli, J.P. Conlon and F. Quevedo, General analysis of LARGE volume scenarios with string loop moduli stabilisation, JHEP 10 (2008) 105 [arXiv:0805.1029] [INSPIRE].ADSCrossRefMathSciNetGoogle Scholar
  45. [45]
    M. Cicoli, S. Downes and B. Dutta, Power suppression at large scales in string inflation, JCAP 12 (2013) 007 [arXiv:1309.3412] [INSPIRE].ADSCrossRefGoogle Scholar

Copyright information

© The Author(s) 2014

Authors and Affiliations

  1. 1.Deutsches Elektronen-Synchrotron DESY, Theory GroupHamburgGermany

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