# Avoiding the blue spectrum and the fine-tuning of initial conditions in hybrid inflation

@article{Clesse2008AvoidingTB, title={Avoiding the blue spectrum and the fine-tuning of initial conditions in hybrid inflation}, author={S{\'e}bastien Clesse and Jonathan Rocher}, journal={Physical Review D}, year={2008}, volume={79}, pages={103507} }

Hybrid inflation faces two well-known problems: the blue spectrum of the non-supersymmetric version of the model and the fine-tuning of the initial conditions of the fields leading to sufficient inflation to account for the standard cosmological problems. They are investigated by studying the exact two-fields dynamics instead of assuming slow-roll. When the field values are restricted to be less than the reduced Planck mass, a non-negligible part of the initial condition space (around 15…

## 31 Citations

### Hybrid Inflation: Multi-field Dynamics and Cosmological Constraints

- Physics
- 2011

The dynamics of hybrid models is usually approximated by the evolution of a scalar field slowly rolling along a nearly flat valley. Inflation ends with a waterfall phase, due to a tachyonic…

### Fractal initial conditions and natural parameter values in hybrid inflation

- Physics
- 2009

We show that the initial field values required to produce inflation in the two fields original hybrid model, and its supergravity F-term extension, do not suffer from any fine-tuning problem, even…

### Implementing Hilltop F-term Hybrid Inflation in Supergravity

- Physics
- 2012

F-term hybrid inflation (FHI) of the hilltop type can generate a scalar spectral index, ns, in agreement with the fitting of the seven-year Wilkinson microwave anisotropy probe data by the standard…

### Large and small field inflation from hyperbolic sigma models

- MathematicsPhysical Review D
- 2022

Long standing themes in inflation include the issue of large field vs. small field inflation as well as the question what fraction of phase space leads to sufficient inflation, and furthermore is…

### An introduction to inflation after Planck: from theory to observations

- Physics
- 2015

These lecture notes have been written for a short introductory course on the status of inflation after Planck and BICEP2, given at the Xth Modave School of Mathematical Physics. The first objective…

### Testing inflation and curvaton scenarios with CMB distortions

- Physics
- 2014

Prior to recombination, Silk damping causes the dissipation of energy from acoustic waves into the monopole of the Cosmic Microwave Background (CMB), resulting in spectral distortions. These can be…

### Hybrid inflation revisited in light of WMAP5 data

- Physics
- 2009

We study the effects of including one-loop radiative corrections in a nonsupersymmetric hybrid inflationary model. These corrections can arise from Yukawa couplings between the inflaton and…

### Remote inflation: hybrid-like inflation without hybrid-type potential

- Environmental Science
- 2009

A new scenario of hybrid-like inflation is considered without using hybrid-type potential. Radiation raised continuously by a dissipating inflaton field keeps symmetry restoration in a remote sector,…

### Recursive stochastic effects in valley hybrid inflation

- Physics
- 2013

Hybrid Inflation is a two-field model where inflation ends by a tachyonic instability, the duration of which is determined by stochastic effects and has important observational implications. Making…

## References

SHOWING 1-10 OF 85 REFERENCES

### New smooth hybrid inflation

- Physics
- 2007

We consider the extension of the supersymmetric Pati-Salam model which solves the b-quark mass problem of supersymmetric grand unified models with exact Yukawa unification and universal boundary…

### The Numerical Treatment of Inflationary Models

- Physics
- 2007

The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology,…

### Primordial fluctuations and cosmological inflation after WMAP 1.0

- Physics
- 2004

The observational constraints on the primordial power spectrum have tightened considerably with the release of the first-year analysis of the WMAP observations, especially when combined with the…

### New shifted hybrid inflation

- Physics
- 2002

A new shifted hybrid inflationary scenario is introduced which, in contrast to the older one, relies only on renormalizable superpotential terms. This scenario is automatically realized in a concrete…

### Little inflatons and gauge inflation

- Physics
- 2003

Cosmological inflation gives a natural answer for a variety of cosmological questions, including the horizon problem, the flatness problem, and others. However, inflation yields new questions…

### Inflationary universe: A possible solution to the horizon and flatness problems

- Physics
- 1981

The standard model of hot big-bang cosmology requires initial conditions which are problematic in two ways: (1) The early universe is assumed to be highly homogeneous, in spite of the fact that…

### Smooth hybrid inflation in supergravity with a running spectral index and early star formation

- Physics
- 2004

It is shown that in a smooth hybrid inflation model in supergravity adiabatic fluctuations with a running spectral index with ${n}_{s}g1$ on a large scale and ${n}_{s}l1$ on a smaller scale can be…

### A Non inflationary model with scale invariant cosmological perturbations

- Physics
- 2007

We show that a contracting universe which bounces due to quantum cosmological effects and connects to the hot big-bang expansion phase, can produce an almost scale invariant spectrum of perturbations…

### A ug 2 00 7 The exact numerical treatment of inflationary models

- Physics
- 2007

The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology,…