Primordial Non-Gaussianities from General Models of Inflation and Bounce

[1] A.H. Guth, The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems, Adv. Ser. Astrophys. Cosmol. 3 (1987) 139.

[2] A.A. Starobinsky, A New Type of Isotropic Cosmological Models Without Singularity, Adv. Ser. Astrophys. Cosmol. 3 (1987) 130.

[3] K. Sato, First Order Phase Transition of a Vacuum and Expansion of the Universe, Mon. Not. Roy. Astron. Soc. 195 (1981) 467.

[4] PLANCK collaboration, Planck 2018 results. X. Constraints on inflation, Astron. Astrophys. 641 (2020) A10 [1807.06211].

[5] A. Borde and A. Vilenkin, Singularities in inflationary cosmology: A Review, Int. J. Mod. Phys. D 5 (1996) 813 [gr-qc/9612036].

[6] J. Martin and R.H. Brandenberger, The TransPlanckian problem of inflationary cosmology, Phys. Rev. D 63 (2001) 123501 [hep-th/0005209].

[7] D. Battefeld and P. Peter, A Critical Review of Classical Bouncing Cosmologies, Phys. Rept. 571 (2015) 1 [1406.2790].

[8] R. Holman and A.J. Tolley, Enhanced Non-Gaussianity from Excited Initial States, JCAP 05 (2008) 001 [0710.1302].

[9] S. Kundu, Non-Gaussianity Consistency Relations, Initial States and Back-reaction, JCAP 04 (2014) 016 [1311.1575].

[10] A. Ashoorioon, Rescuing Single Field Inflation from the Swampland, Phys. Lett. B 790 (2019) 568 [1810.04001].

[11] S. Weinberg, Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity, John Wiley and Sons, New York (1972).

[12] E.W. Kolb and M.S. Turner, The Early Universe, vol. 69 (1990).

[13] SUPERNOVA SEARCH TEAM collaboration, Observational evidence from supernovae for an accelerating universe and a cosmological constant, Astron. J. 116 (1998) 1009 [astro-ph/9805201].

[14] S. Weinberg, Anthropic Bound on the Cosmological Constant, Phys. Rev. Lett. 59 (1987) 2607.

[15] PLANCK collaboration, Planck 2018 results. VI. Cosmological parameters, Astron. Astrophys. 641 (2020) A6 [1807.06209].

[16] A.D. Linde, Chaotic Inflation, Phys. Lett. B 129 (1983) 177.

[17] C. Armendariz-Picon, T. Damour and V.F. Mukhanov, k - inflation, Phys. Lett. B 458 (1999) 209 [hep-th/9904075].

[18] T. Kobayashi, M. Yamaguchi and J. Yokoyama, G-inflation: Inflation driven by the Galileon field, Phys. Rev. Lett. 105 (2010) 231302 [1008.0603].

[19] C. Deffayet, X. Gao, D. Steer and G. Zahariade, From k-essence to generalised Galileons, Phys. Rev. D 84 (2011) 064039 [1103.3260].

[20] T. Kobayashi, M. Yamaguchi and J. Yokoyama, Generalized G-inflation: Inflation with the most general second-order field equations, Prog. Theor. Phys. 126 (2011) 511 [1105.5723].

[21] G.W. Horndeski, Second-order scalar-tensor field equations in a four-dimensional space, Int. J. Theor. Phys. 10 (1974) 363.

[22] R.H. Brandenberger, The Matter Bounce Alternative to Inflationary Cosmology, 1206.4196.

[23] J.-L. Lehners, Ekpyrotic and Cyclic Cosmology, Phys. Rept. 465 (2008) 223 [0806.1245].

[24] T. Qiu, X. Gao and E.N. Saridakis, Towards anisotropy-free and nonsingular bounce cosmology with scale-invariant perturbations, Phys. Rev. D 88 (2013) 043525 [1303.2372].

[25] Y.-F. Cai, D.A. Easson and R. Brandenberger, Towards a Nonsingular Bouncing Cosmology, JCAP 08 (2012) 020 [1206.2382].

[26] V.F. Mukhanov, H. Feldman and R.H. Brandenberger, Theory of cosmological perturbations. Part 1. Classical perturbations. Part 2. Quantum theory of perturbations. Part 3. Extensions, Phys. Rept. 215 (1992) 203.

[27] R.L. Arnowitt, S. Deser and C.W. Misner, The Dynamics of general relativity, Gen. Rel. Grav. 40 (2008) 1997 [gr-qc/0405109].

[28] V. Rubakov, The Null Energy Condition and its violation, Usp. Fiz. Nauk 184 (2014) 137 [1401.4024].

[29] V. Mukhanov and S. Winitzki, Introduction to quantum effects in gravity, Cambridge University Press (6, 2007).

[30] T. Bunch and P. Davies, Quantum Field Theory in de Sitter Space: Renormalization by Point Splitting, Proc. Roy. Soc. Lond. A 360 (1978) 117.

[31] M. Mylova, O. O¨ zsoy, S. Parameswaran, G. Tasinato and I. Zavala, A new mechanism to enhance primordial tensor fluctuations in single field inflation, JCAP 12 (2018) 024 [1808.10475].

[32] J.M. Maldacena, Non-Gaussian features of primordial fluctuations in single field inflationary models, JHEP 05 (2003) 013 [astro-ph/0210603].

[33] E. Komatsu and D.N. Spergel, Acoustic signatures in the primary microwave background bispectrum, Phys. Rev. D 63 (2001) 063002 [astro-ph/0005036].

[34] D. Babich, P. Creminelli and M. Zaldarriaga, The Shape of non-Gaussianities, JCAP 08 (2004) 009 [astro-ph/0405356].

[35] J. Fergusson and E. Shellard, The shape of primordial non-Gaussianity and the CMB bispectrum, Phys. Rev. D 80 (2009) 043510 [0812.3413].

[36] PLANCK collaboration, Planck 2018 results. IX. Constraints on primordial non-Gaussianity, 1905.05697.

[37] X. Chen, M.-x. Huang, S. Kachru and G. Shiu, Observational signatures and non-Gaussianities of general single field inflation, JCAP 01 (2007) 002 [hep-th/0605045].

[38] J. Soda, H. Kodama and M. Nozawa, Parity Violation in Graviton Non-gaussianity, JHEP 08 (2011) 067 [1106.3228].

[39] X. Gao, T. Kobayashi, M. Yamaguchi and J. Yokoyama, Primordial non-Gaussianities of gravitational waves in the most general single-field inflation model, Phys. Rev. Lett. 107 (2011) 211301 [1108.3513].

[40] D. Pirtskhalava, L. Santoni, E. Trincherini and P. Uttayarat, Inflation from Minkowski Space, JHEP 12 (2014) 151 [1410.0882].

[41] T. Qiu and Y.-T. Wang, G-Bounce Inflation: Towards Nonsingular Inflation Cosmology with Galileon Field, JHEP 04 (2015) 130 [1501.03568].

[42] M. Libanov, S. Mironov and V. Rubakov, Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis, JCAP 08 (2016) 037 [1605.05992].

[43] T. Kobayashi, M. Yamaguchi and J. Yokoyama, Galilean Creation of the Inflationary Universe, JCAP 07 (2015) 017 [1504.05710].

[44] P. Creminelli, J. Gleyzes, J. Noren˜a and F. Vernizzi, Resilience of the standard predictions for primordial tensor modes, Phys. Rev. Lett. 113 (2014) 231301 [1407.8439].

[45] P. Creminelli, D. Pirtskhalava, L. Santoni and E. Trincherini, Stability of Geodesically Complete Cosmologies, JCAP 11 (2016) 047 [1610.04207].

[46] Y. Cai, Y. Wan, H.-G. Li, T. Qiu and Y.-S. Piao, The Effective Field Theory of nonsingular cosmology, JHEP 01 (2017) 090 [1610.03400].

[47] S. Akama and T. Kobayashi, Generalized multi-Galileons, covariantized new terms, and the no-go theorem for nonsingular cosmologies, Phys. Rev. D 95 (2017) 064011 [1701.02926].

[48] S. Akama and T. Kobayashi, General theory of cosmological perturbations in open and closed universes from the Horndeski action, Phys. Rev. D 99 (2019) 043522 [1810.01863].

[49] M. Fukushima, Y. Misonoh, S. Miyashita and S. Sato, Stable singularity-free cosmological solutions in nonprojectable Hoˇrava-Lifshitz gravity, Phys. Rev. D 99 (2019) 064004 [1812.10295].

[50] N. Afshordi, D.J. Chung and G. Geshnizjani, Cuscuton: A Causal Field Theory with an Infinite Speed of Sound, Phys. Rev. D 75 (2007) 083513 [hep-th/0609150].

[51] S.S. Boruah, H.J. Kim, M. Rouben and G. Geshnizjani, Cuscuton bounce, JCAP 08 (2018) 031 [1802.06818].

[52] J. Quintin, Z. Sherkatghanad, Y.-F. Cai and R.H. Brandenberger, Evolution of cosmological perturbations and the production of non-Gaussianities through a nonsingular bounce: Indications for a no-go theorem in single field matter bounce cosmologies, Phys. Rev. D 92 (2015) 063532 [1508.04141].

[53] Y.-B. Li, J. Quintin, D.-G. Wang and Y.-F. Cai, Matter bounce cosmology with a generalized single field: non-Gaussianity and an extended no-go theorem, JCAP 03 (2017) 031 [1612.02036].

[54] Y.-F. Cai, W. Xue, R. Brandenberger and X. Zhang, Non-Gaussianity in a Matter Bounce, JCAP 05 (2009) 011 [0903.0631].

[55] S. Akama, S. Hirano and T. Kobayashi, Primordial non-Gaussianities of scalar and tensor perturbations in general bounce cosmology: Evading the no-go theorem, Phys. Rev. D 101 (2020) 043529 [1908.10663].

[56] D. Wands, Duality invariance of cosmological perturbation spectra, Phys. Rev. D 60 (1999) 023507 [gr-qc/9809062].

[57] F. Finelli and R. Brandenberger, On the generation of a scale invariant spectrum of adiabatic fluctuations in cosmological models with a contracting phase, Phys. Rev. D 65 (2002) 103522 [hep-th/0112249].

[58] R.N. Raveendran, D. Chowdhury and L. Sriramkumar, Viable tensor-to-scalar ratio in a symmetric matter bounce, JCAP 01 (2018) 030 [1703.10061].

[59] R.N. Raveendran and L. Sriramkumar, Viable scalar spectral tilt and tensor-to-scalar ratio in near-matter bounces, Phys. Rev. D 100 (2019) 083523 [1812.06803].

[60] X. Gao, Y. Wang, W. Xue and R. Brandenberger, Fluctuations in a Horava-Lifshitz Bouncing Cosmology, JCAP 02 (2010) 020 [0911.3196].

[61] T. Kobayashi, Generic instabilities of nonsingular cosmologies in Horndeski theory: A no-go theorem, Phys. Rev. D 94 (2016) 043511 [1606.05831].

[62] D. Nandi and L. Sriramkumar, Can a nonminimal coupling restore the consistency condition in bouncing universes?, Phys. Rev. D 101 (2020) 043506 [1904.13254].

[63] X. Gao and D.A. Steer, Inflation and primordial non-Gaussianities of ’generalized Galileons’, JCAP 12 (2011) 019 [1107.2642].

[64] A. De Felice and S. Tsujikawa, Inflationary non-Gaussianities in the most general second-order scalar-tensor theories, Phys. Rev. D 84 (2011) 083504 [1107.3917].

[65] X. Gao, T. Kobayashi, M. Shiraishi, M. Yamaguchi, J. Yokoyama and S. Yokoyama, Full bispectra from primordial scalar and tensor perturbations in the most general single-field inflation model, PTEP 2013 (2013) 053E03 [1207.0588].

[66] F. Arroja and T. Tanaka, A note on the role of the boundary terms for the non-Gaussianity in general k-inflation, JCAP 05 (2011) 005 [1103.1102].

[67] G. Rigopoulos, Gauge invariance and non-Gaussianity in Inflation, Phys. Rev. D 84 (2011) 021301 [1104.0292].

[68] C. Burrage, R.H. Ribeiro and D. Seery, Large slow-roll corrections to the bispectrum of noncanonical inflation, JCAP 07 (2011) 032 [1103.4126].

[69] D. Chowdhury, V. Sreenath and L. Sriramkumar, The tensor bi-spectrum in a matter bounce, JCAP 11 (2015) 002 [1506.06475].

[70] R. Kothari and D. Nandi, B-Mode auto-bispectrum due to matter bounce, JCAP 10 (2019) 026 [1901.06538].

[71] O. Ozsoy, M. Mylova, S. Parameswaran, C. Powell, G. Tasinato and I. Zavala, Squeezed tensor non-Gaussianity in non-attractor inflation, JCAP 09 (2019) 036 [1902.04976].

[72] S. Akama, S. Hirano and T. Kobayashi, Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states, Phys. Rev. D 102 (2020) 023513 [2003.10686].

[73] W. Xue and B. Chen, alpha-vacuum and inflationary bispectrum, Phys. Rev. D 79 (2009) 043518 [0806.4109].

[74] P.D. Meerburg, J.P. van der Schaar and P.S. Corasaniti, Signatures of Initial State Modifications on Bispectrum Statistics, JCAP 05 (2009) 018 [0901.4044].

[75] P. Meerburg, J.P. van der Schaar and M.G. Jackson, Bispectrum signatures of a modified vacuum in single field inflation with a small speed of sound, JCAP 02 (2010) 001 [0910.4986].

[76] X. Chen, Primordial Non-Gaussianities from Inflation Models, Adv. Astron. 2010 (2010) 638979 [1002.1416].

[77] P. Meerburg, Oscillations in the Primordial Bispectrum I: Mode Expansion, Phys. Rev. D 82 (2010) 063517 [1006.2771].

[78] X. Chen, Folded Resonant Non-Gaussianity in General Single Field Inflation, JCAP 12 (2010) 003 [1008.2485].

[79] P. Meerburg and J.P. van der Schaar, Minimal cut-off vacuum state constraints from CMB bispectrum statistics, Phys. Rev. D 83 (2011) 043520 [1009.5660].

[80] I. Agullo and L. Parker, Non-gaussianities and the Stimulated creation of quanta in the inflationary universe, Phys. Rev. D 83 (2011) 063526 [1010.5766].

[81] A. Ashoorioon and G. Shiu, A Note on Calm Excited States of Inflation, JCAP 03 (2011) 025 [1012.3392].

[82] J. Ganc, Calculating the local-type fNL for slow-roll inflation with a non-vacuum initial state, Phys. Rev. D 84 (2011) 063514 [1104.0244].

[83] J. Ganc and E. Komatsu, Scale-dependent bias of galaxies and mu-type distortion of the cosmic microwave background spectrum from single-field inflation with a modified initial state, Phys. Rev. D 86 (2012) 023518 [1204.4241].

[84] N. Agarwal, R. Holman, A.J. Tolley and J. Lin, Effective field theory and non-Gaussianity from general inflationary states, JHEP 05 (2013) 085 [1212.1172].

[85] J.-O. Gong and M. Sasaki, Squeezed primordial bispectrum from general vacuum state, Class. Quant. Grav. 30 (2013) 095005 [1302.1271].

[86] R. Flauger, D. Green and R.A. Porto, On squeezed limits in single-field inflation. Part I, JCAP 08 (2013) 032 [1303.1430].

[87] A. Aravind, D. Lorshbough and S. Paban, Non-Gaussianity from Excited Initial Inflationary States, JHEP 07 (2013) 076 [1303.1440].

[88] A. Ashoorioon, K. Dimopoulos, M. Sheikh-Jabbari and G. Shiu, Reconciliation of High Energy Scale Models of Inflation with Planck, JCAP 02 (2014) 025 [1306.4914].

[89] S. Brahma, E. Nelson and S. Shandera, Fossilized Gravitational Wave Relic and Primordial Clocks, Phys. Rev. D 89 (2014) 023507 [1310.0471].

[90] S. Bahrami and E.E. Flanagan, Primordial non-Gaussianities in single field inflationary models with non-trivial initial states, JCAP 10 (2014) 010 [1310.4482].

[91] R. Emami, H. Firouzjahi and M. Zarei, Anisotropic inflation with the nonvacuum initial state, Phys. Rev. D 90 (2014) 023504 [1401.4406].

[92] S. Zeynizadeh and A.R. Akbarieh, Higgs Inflation and General Initial Conditions, Eur. Phys. J. C 75 (2015) 355 [1504.00482].

[93] P.D. Meerburg and M. Mu¨nchmeyer, Optimal CMB estimators for bispectra from excited states, Phys. Rev. D 92 (2015) 063527 [1505.05882].

[94] A. Ashoorioon, R. Casadio and T. Koivisto, Anisotropic non-Gaussianity from Rotational Symmetry Breaking Excited Initial States, JCAP 12 (2016) 002 [1605.04758].

[95] A. Shukla, S.P. Trivedi and V. Vishal, Symmetry constraints in inflation, α-vacua, and the three point function, JHEP 12 (2016) 102 [1607.08636].

[96] J. Gleyzes, D. Langlois, F. Piazza and F. Vernizzi, Healthy theories beyond Horndeski, Phys. Rev. Lett. 114 (2015) 211101 [1404.6495].

[97] X. Gao, Unifying framework for scalar-tensor theories of gravity, Phys. Rev. D 90 (2014) 081501 [1406.0822].

[98] M. Giovannini, The refractive index of relic gravitons, Class. Quant. Grav. 33 (2016) 125002 [1507.03456].

[99] Y. Cai, Y.-T. Wang and Y.-S. Piao, Is there an effect of a nontrivial cT during inflation?, Phys. Rev. D 93 (2016) 063005 [1510.08716].

[100] Y. Cai, Y.-T. Wang and Y.-S. Piao, Propagating speed of primordial gravitational waves and inflation, Phys. Rev. D 94 (2016) 043002 [1602.05431].

[101] M. Giovannini, The propagating speed of relic gravitational waves and their refractive index during inflation, Eur. Phys. J. C 78 (2018) 442 [1803.05203].

[102] M. Giovannini, Blue and violet graviton spectra from a dynamical refractive index, Phys. Lett. B 789 (2019) 502 [1805.08142].

[103] A. Ashoorioon, K. Dimopoulos, M. Sheikh-Jabbari and G. Shiu, Non-Bunch–Davis initial state reconciles chaotic models with BICEP and Planck, Phys. Lett. B 737 (2014) 98 [1403.6099].

[104] A. Agrawal, T. Fujita and E. Komatsu, Tensor Non-Gaussianity from Axion-Gauge-Fields Dynamics : Parameter Search, JCAP 06 (2018) 027 [1802.09284].

[105] H.W. Tahara and J. Yokoyama, CMB B-mode auto-bispectrum produced by primordial gravitational waves, PTEP 2018 (2018) 013E03 [1704.08904].

[106] P. Creminelli, A. Nicolis and E. Trincherini, Galilean Genesis: An Alternative to inflation, JCAP 11 (2010) 021 [1007.0027].

[107] V. Belinsky, I. Khalatnikov and E. Lifshitz, Oscillatory approach to a singular point in the relativistic cosmology, Adv. Phys. 19 (1970) 525.

[108] J. Khoury, B.A. Ovrut, P.J. Steinhardt and N. Turok, The Ekpyrotic universe: Colliding branes and the origin of the hot big bang, Phys. Rev. D 64 (2001) 123522 [hep-th/0103239].

[109] Y.-F. Cai, R. Brandenberger and P. Peter, Anisotropy in a Nonsingular Bounce, Class. Quant. Grav. 30 (2013) 075019 [1301.4703].

[110] C. Lin, J. Quintin and R.H. Brandenberger, Massive gravity and the suppression of anisotropies and gravitational waves in a matter-dominated contracting universe, JCAP 01 (2018) 011 [1711.10472].

[111] S. Nishi and T. Kobayashi, Generalized Galilean Genesis, JCAP 03 (2015) 057 [1501.02553].

[112] H.W. Tahara, S. Nishi, T. Kobayashi and J. Yokoyama, Self-anisotropizing inflationary universe in Horndeski theory and beyond, JCAP 07 (2018) 058 [1805.00186].