Inflationary Cosmological Perturbations of Quantum-Mechanical Origin

Martin, Jérôme

doi:10.1007/11377306_7

Cited by 83 publications

(76 citation statements)

References 36 publications

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“…interactions between cosmological fluids. On the other hand, this kind of interactions is broadly used in cosmology, with the coupling between inflaton and radiation during reheating (e.g., [20]) or the one between dark matter and dark energy (e.g., [8,21,22]), or even the decay of heavy matter particles like WIMPS into light relativistic particles (e.g., [23]). Modern cosmology make strong use of coupled fluids for a variety of purposes, therefore making this study of coupled models in terms of Lotka-Volterra systems of first heuristic interest.…”

Section: Cooperation In the Jungle Universes A General Dynamics mentioning

confidence: 99%

The Jungle Universe: coupled cosmological models in a Lotka–Volterra framework

et al. 2014

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In this paper, we exploit the fact that the dynamics of homogeneous and isotropic FriedmannLemaître universes is a special case of generalized Lotka-Volterra system where the competitive species are the barotropic fluids filling the Universe. Without coupling between those fluids, LotkaVolterra formulation offers a pedagogical and simple way to interpret usual Friedmann-Lemaître cosmological dynamics. A natural and physical coupling between cosmological fluids is proposed which preserve the structure of the dynamical equations. Using the standard tools of LotkaVolterra dynamics, we obtain the general Lyapunov function of the system when one of the fluids is coupled to dark energy. This provides in a rigorous form a generic asymptotic behavior for cosmic expansion in presence of coupled species, beyond the standard de Sitter, Einstein-de Sitter and Milne cosmologies. Finally, we conjecture that chaos can appear for at least four interacting fluids.

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Section: Cooperation In the Jungle Universes A General Dynamics mentioning

confidence: 99%

The Jungle Universe: coupled cosmological models in a Lotka–Volterra framework

et al. 2014

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“…By definition, inflation is a phase of accelerated expansion for which the scale factor satisfies [12,13,14,15] …”

Section: Basics Of Inflationmentioning

confidence: 99%

“…A possible implementation of the inflationary scenario is to assume that the matter content of the universe is described by a scalar field φ(η) with a potential V (φ) since, when V (φ) is sufficiently flat, the effective pressure of the scalar field can be negative [12,13,16,14,15]. In this article, we restrict ourselves to the case of a single scalar field.…”

Section: Plmentioning

confidence: 99%

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Inflation after WMAP3: confronting the slow-roll and exact power spectra with CMB data

Martin

Ringeval

2006

J. Cosmol. Astropart. Phys.

242

374

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Abstract.The implications of the WMAP (Wilkinson Microwave Anisotropy Probe) third year data for inflation are investigated using both the slow-roll approximation and an exact numerical integration of the inflationary power spectra including a phenomenological modelling of the reheating era. At slow-roll leading order, the constraints ǫ 1 < 0.022 and −0.07 < ǫ 2 < 0.07 are obtained at 95% CL (Confidence Level) implying a tensor-to-scalar ratio r 10 < 0.21 and a Hubble parameter during inflation H/m Pl < 1.3 × 10 −5 . At next-to-leading order, a tendency for ǫ 3 > 0 is observed. With regards to the exact numerical integration, large field models, V (φ) ∝ φ p , with p > 3.1 are now excluded at 95% CL. Small field models, V (φ) ∝ 1 − (φ/µ) p , are still compatible with the data for all values of p. However, if µ/m Pl < 10 is assumed, then the case p = 2 is slightly disfavoured. In addition, mild constraints on the reheating temperature for an extreme equation of state w reh −1/3 are found, namely T reh > 2 TeV at 95% CL. Hybrid models are disfavoured by the data, the best fit model having ∆χ 2 ≃ +5 with two extra parameters in comparison with large field models. Running mass models remain compatible, but no prior independent constraints can be obtained. Finally, superimposed oscillations of trans-Planckian origin are studied. The vanilla slow-roll model is still the most probable one. However, the overall statistical weight in favour of superimposed oscillations has increased in comparison with the WMAP first year data, the amplitude of the oscillations satisfying 2|x|σ 0 < 0.76 at 95% CL. The best fit model leads to an improvement of ∆χ 2 ≃ −12 for 3 extra parameters. Moreover, compared to other oscillatory patterns, the logarithmic shape is favoured.

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“…This difference can lead to electric currents and hence magnetic fields. If the scale of cluster magnetic fields is as large as ∼ Mpc, however, it is unlikely that the origin of such a large-scale magnetic field is in astrophysical processes and we are tempted to assign the origin of cosmological magnetic field to the processes during inflation in the early Universe which stretches coherent scales exponentially [12,13,14,15,16,17,18,19,20].…”

Section: Introductionmentioning

confidence: 99%

Generation of large scale magnetic fields in single-field inflation

Martin

Yokoyama

2008

J. Cosmol. Astropart. Phys.

266

385

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Abstract. We consider the generation of large-scale magnetic fields in slow-roll inflation. The inflaton field is described in a supergravity framework where the conformal invariance of the electromagnetic field is generically and naturally broken. For each class of inflationary scenarios, we determine the functional dependence of the gauge coupling that is consistent with the observations on the magnetic field strength at various astrophysical scales and, at the same time, avoid a back-reaction problem. Then, we study whether the required coupling functions can naturally emerge in wellmotivated, possibly string-inspired, models. We argue that this is non trivial and can be realized only for a restricted class of scenarios. This includes power-law inflation where the inflaton field is interpreted as a modulus. However, this scenario seems to be consistent only if the energy scale of inflation is low and the reheating stage prolonged.Another reasonable possibility appears to be small field models since no back-reaction problem is present in this case but, unfortunately, the corresponding scenario cannot be justified in a stringy framework. Finally, large field models do not lead to sensible model building.PACS numbers: 98.80.Cq, 98.70.Vc

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Inflationary Cosmological Perturbations of Quantum-Mechanical Origin

Cited by 83 publications

References 36 publications

The Jungle Universe: coupled cosmological models in a Lotka–Volterra framework

The Jungle Universe: coupled cosmological models in a Lotka–Volterra framework

Inflation after WMAP3: confronting the slow-roll and exact power spectra with CMB data

Generation of large scale magnetic fields in single-field inflation

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