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Non-Gaussianity from excited initial inflationary states. (English) Zbl 1342.83513

Summary: We study squeezed limit \(f_{\mathrm{NL}}\) generation by excited initial inflationary states in a model independent way. We restrict ‘excited’ to mean a Bogoliubov transformation of the Bunch Davies state. We simultaneously impose the constraints that the observable power spectrum is nearly scale invariant over at least three decades and that the observable modes today be subhorizon at the beginning of inflation while not causing significant back-reaction. We show that most excited initial inflationary states for single field inflationary models with negligible superhorizon evolution do not produce an observable squeezed limit \(f_{\mathrm{NL}}\). The case in which one mode is in the Bunch Davies state while the other two modes are in an excited state with \(0.01<|\beta_k|\leq 0.1\) may generate a squeezed limit \(f_{\mathrm{NL}}\) which is detectable with future experiments.

MSC:

83F05 Relativistic cosmology
81T16 Nonperturbative methods of renormalization applied to problems in quantum field theory

References:

[1] WMAP collaboration, G. Hinshaw et al., Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results, arXiv:1212.5226 [INSPIRE].
[2] B.R. Greene, K. Schalm, G. Shiu and J.P. van der Schaar, Decoupling in an expanding universe: Backreaction barely constrains short distance effects in the CMB, JCAP02 (2005) 001 [hep-th/0411217] [INSPIRE]. · doi:10.1088/1475-7516/2005/02/001
[3] X. Chen, M.-x. Huang, S. Kachru and G. Shiu, Observational signatures and non-Gaussianities of general single field inflation, JCAP01 (2007) 002 [hep-th/0605045] [INSPIRE]. · doi:10.1088/1475-7516/2007/01/002
[4] R. Holman and A.J. Tolley, Enhanced Non-Gaussianity from Excited Initial States, JCAP05 (2008) 001 [arXiv:0710.1302] [INSPIRE]. · doi:10.1088/1475-7516/2008/05/001
[5] I. Agullo and L. Parker, Non-Gaussianities and the Stimulated creation of quanta in the inflationary universe, Phys. Rev.D 83 (2011) 063526 [arXiv:1010.5766] [INSPIRE].
[6] I. Agullo and L. Parker, Stimulated creation of quanta during inflation and the observable universe, Gen. Rel. Grav.43 (2011) 2541 [Int. J. Mod. Phys.D 20 (2011) 2861] [arXiv:1106.4240] [INSPIRE]. · Zbl 1228.83114 · doi:10.1007/s10714-011-1220-8
[7] J. Ganc, Calculating the local-type fNLfor slow-roll inflation with a non-vacuum initial state, Phys. Rev.D 84 (2011) 063514 [arXiv:1104.0244] [INSPIRE].
[8] D. Carney, W. Fischler, S. Paban and N. Sivanandam, The Inflationary Wavefunction and its Initial Conditions, JCAP12 (2012) 012 [arXiv:1109.6566] [INSPIRE]. · doi:10.1088/1475-7516/2012/12/012
[9] D. Chialva, Signatures of very high energy physics in the squeezed limit of the bispectrum (violation of Maldacena’s condition), JCAP10 (2012) 037 [arXiv:1108.4203] [INSPIRE].
[10] S. Kundu, Inflation with General Initial Conditions for Scalar Perturbations, JCAP02 (2012) 005 [arXiv:1110.4688] [INSPIRE]. · doi:10.1088/1475-7516/2012/02/005
[11] N. Agarwal, R. Holman, A.J. Tolley and J. Lin, Effective field theory and non-Gaussianity from general inflationary states, JHEP05 (2013) 085 [arXiv:1212.1172] [INSPIRE]. · Zbl 1342.83511 · doi:10.1007/JHEP05(2013)085
[12] J.-O. Gong and M. Sasaki, Squeezed primordial bispectrum from general vacuum state, Class. Quant. Grav.30 (2013) 095005 [arXiv:1302.1271] [INSPIRE]. · Zbl 1269.83070 · doi:10.1088/0264-9381/30/9/095005
[13] M.H. Namjoo, H. Firouzjahi and M. Sasaki, Violation of non-Gaussianity consistency relation in a single field inflationary model, Europhys. Lett.101 (2013) 39001 [arXiv:1210.3692] [INSPIRE]. · doi:10.1209/0295-5075/101/39001
[14] X. Chen, H. Firouzjahi, M.H. Namjoo and M. Sasaki, A Single Field Inflation Model with Large Local Non-Gaussianity, Europhys. Lett.102 (2013) 59001 [arXiv:1301.5699] [INSPIRE]. · doi:10.1209/0295-5075/102/59001
[15] A. Dey and S. Paban, Non-Gaussianities in the Cosmological Perturbation Spectrum due to Primordial Anisotropy, JCAP04 (2012) 039 [arXiv:1106.5840] [INSPIRE]. · doi:10.1088/1475-7516/2012/04/039
[16] H.V. Peiris and L. Verde, The Shape of the Primordial Power Spectrum: A Last Stand Before Planck, Phys. Rev.D 81 (2010) 021302 [arXiv:0912.0268] [INSPIRE].
[17] C.R. Contaldi, M. Peloso, L. Kofman and A.D. Linde, Suppressing the lower multipoles in the CMB anisotropies, JCAP07 (2003) 002 [astro-ph/0303636] [INSPIRE]. · Zbl 1027.83531 · doi:10.1088/1475-7516/2003/07/002
[18] R. Flauger, D. Green and R.A. Porto, On Squeezed Limits in Single-Field Inflation - Part I, arXiv:1303.1430 [INSPIRE].
[19] J.M. Maldacena, Non-Gaussian features of primordial fluctuations in single field inflationary models, JHEP05 (2003) 013 [astro-ph/0210603] [INSPIRE]. · doi:10.1088/1126-6708/2003/05/013
[20] D. Baumann, TASI Lectures on Inflation, arXiv:0907.5424 [INSPIRE].
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