Spectrum oscillations from features in the potential of single-field inflation

Dalianis, Ioannis; Kodaxis, George P.; Stamou, Ioanna D.; Tetradis, N.; Tsigkas-Kouvelis, A.

doi:10.1103/physrevd.104.103510

Cited by 43 publications

(51 citation statements)

References 137 publications

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“…Furthermore, we note that peaks in the power spectrum can also be related to the existence of one or more sharp drops (steps) in the inflaton potential [107,108]. One could replace the inflection point with one or more sharp steps sufficiently close to each other and an analogous results can be attained.…”

Section: Inflection Pointmentioning

confidence: 76%

“…In single field models, the special feature that amplifies the power spectrum can be either an inflection point [104][105][106] or a step-like transition in the inflationary plateau [107,108] 4 . The presence of step-like, or generally sharp, features in the inflation potential results in amplification and, additionally, in oscillatory patterns in the curvature power spectrum [108,111]. The potential might feature more than one steps, so that the relevant enhancement in the power spectrum becomes strong enough.…”

Section: Pbhs From Runaway Inflation Modelsmentioning

confidence: 99%

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Reheating in Runaway Inflation Models via the Evaporation of Mini Primordial Black Holes

Dalianis

Kodaxis

2022

Galaxies

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We investigate the cosmology of mini Primordial Black Holes (PBHs) produced by large density perturbations that collapse during a stiff fluid domination phase. Such a phase can be realized by a runaway-inflaton model that crosses an inflection point or a sharp feature at the last stage of inflation. Mini PBHs evaporate promptly and reheat the early universe. In addition, we examine two notable implications of this scenario: the possible presence of PBH evaporation remnants in galaxies and a non-zero residual potential energy density for the runaway inflaton that might play the role of the dark energy. We specify the parameter space that this scenario can be realized and we find that a transit PBH domination phase is necessary due to gravitational wave (GW) constraints. A distinct prediction of the scenario is a compound GW signal that might be probed by current and future experiments. We also demonstrate our results employing an explicit inflation model.

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Section: Inflection Pointmentioning

confidence: 76%

Section: Pbhs From Runaway Inflation Modelsmentioning

confidence: 99%

Reheating in Runaway Inflation Models via the Evaporation of Mini Primordial Black Holes

Dalianis

Kodaxis

2022

Galaxies

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“…In particular, one can identify sharp features, caused by a sudden transition in a background quantity during inflation and characterised by oscillations linear in the frequency f , and resonant features, associated with an oscillation in a background quantity and exhibiting a periodic modulation in ln(f ). What is interesting for GW astronomy is that, as has been seen in [9][10][11][12][13][14][15], the scalar-induced GW spectrum related to these scales also exhibits oscillations in the frequency profile. For example, the post-inflationary era induced contribution to the energy density fraction in GWs has been shown to take the form [9,11,13]:…”

Section: Introductionmentioning

confidence: 93%

“…A more accurate description of these data can be obtained by introducing an additional Lognormal contribution to the likelihood [35] which allows for a better modeling of the skewness contribution, reducing the bias in the estimate of the θ. However, since this low-bias is irrelevant for the purpose of the present analysis (which only aims at recognizing the frequency shape of the SGWB), and in order to provide a likelihood which is quadratic in the model parameters 12 , we stick to the Gaussian approximation given in eq. (3.2).…”

Section: Principal Component Analysismentioning

confidence: 99%

Detecting primordial features with LISA

Fumagalli,

Pieroni,

Renaux-Petel

et al. 2021

Preprint

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Oscillations in the frequency profile of the stochastic gravitational wave background are a characteristic prediction of small-scale features during inflation. In this paper we present a first investigation of the detection prospects of such oscillations with the upcoming space-based gravitational wave observatory LISA. As a proof of principle, we show for a selection of feature signals that the oscillations can be reconstructed with LISA, employing a method based on principal component analysis. We then perform a Fisher forecast for the parameters describing the oscillatory signal. For a sharp feature we distinguish between the contributions to the stochastic gravitational wave background induced during inflation and in the post-inflationary period, which peak at different frequencies. We find that for the latter case the amplitude of the oscillation is expected to be measurable with < 10% accuracy if the corresponding peak satisfies h 2 Ω GW 10 −12 -10 −11 , while for inflationary-era gravitational waves a detection of the oscillations requires a higher peak amplitude of h 2 Ω GW , as the oscillations only appear on the UV tail of the spectrum. For a resonant feature the detection prospects with LISA are maximised if the frequency of the oscillation falls into the range ω log = 4 to 10. Our results confirm that oscillations in the frequency profile of the stochastic gravitational wave background are a worthwhile target for future detection efforts and offer a key for experimentally testing inflation at small scales.

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“…The details of the dynamics are given in [1,72] and we will not repeat them here. We should mention the other works which have recently explored bumpy early universe dynamics to generate relic gravity waves [74][75][76][77][78][79][80].…”

Section: Variations For Bicep3mentioning

confidence: 99%

Very Hairy Inflation

D'Amico,

Kaloper,

Westphal

2021

Preprint

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We revisit the rollercoaster cosmology based on multiple stages of monodromy inflation. Working within the framework of effective flux monodromy field theory, we include the full range of strong coupling corrections to the inflaton sector. We find that flattened potentials V ∼ φ p + . . . with p < ∼ 1/2, limited to N < ∼ 25 − 40 efolds in the first stage of inflation, continue to fit the CMB. They yield 0.96 < ∼ n s < ∼ 0.97, and produce relic gravity waves with 0.006 < ∼ r < ∼ 0.035, in full agreement with the most recent bounds from BICEP/Keck. The nonlinear derivative corrections generated by strong dynamics in EFT also lead to equilateral non-Gaussianity f eq N L O(1) − O(10), close to the current observational bounds. Finally, in multi-stage rollercoaster, an inflaton-hidden sector U (1) coupling can produce a tachyonic chiral vector background, which converts rapidly into tensors during the short interruption by matter domination. The produced stochastic gravity waves are chiral, and so they may be clearly identifiable by gravity wave instruments like LISA, Big Bang Observatory, Einstein Telescope, NANOgrav or SKA, depending on the precise model realization. We also point out that the current attempts to resolve the H 0 tension using early dark energy generically raise n s . This may significantly alter the impact of BICEP/Keck data on models of inflation.

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Spectrum oscillations from features in the potential of single-field inflation

Cited by 43 publications

References 137 publications

Reheating in Runaway Inflation Models via the Evaporation of Mini Primordial Black Holes

Reheating in Runaway Inflation Models via the Evaporation of Mini Primordial Black Holes

Detecting primordial features with LISA

Very Hairy Inflation

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