Constraints on the scalar-field potential in warm inflation

Abstract

We quantify the degree of fine tuning required to achieve an observationally viable period of inflation in the strongly dissipative regime of warm inflation. The ``fine-tuning'' parameter $\lambda$ is taken to be the ratio of the change in the height of the potential $\Delta V$ to the change in the scalar field $(\Delta \varphi {)}^4$, i.e. the width of the potential, and therefore measures the requisite degree of flatness in the potential. The best motivated warm inflationary scenarios involve a dissipation rate of the kind $\Gamma \propto T^c$ with $c\ge 0$, and for all such cases, the bounds on $\lambda$ are tighter than those for standard cold inflation by at least 3 orders of magnitude. In other words, these models require an even flatter potential than standard inflation. On the other hand for the case of warm inflation with $c<0$, we find that in a strongly dissipative regime the bound on $\lambda$ can significantly weaken with respect to cold inflation. Thus, if a warm inflation model can be constructed in a strongly dissipative, negatively temperature-dependent regime, it accommodates steeper potentials otherwise ruled out in standard inflation.

arXiv comment6 pages, Preprint Numbers: UTWI-03-2022, NORDITA 2022-068, Replacement due to typo on DOE acknowledgement number

References in corpus (20)

• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• Warm Inflation
• Thermally Induced Density Perturbations in the Inflation Era
• Warm Inflation and its Microphysical Basis
• Scalar perturbation spectra from warm inflation
• Strong Dissipative Behavior in Quantum Field Theory
• Interpolating the Stage of Exponential Expansion in the Early Universe: a possible alternative with no reheating
• Warm Little Inflaton
• Dissipation coefficients from scalar and fermion quantum field interactions
• General dissipation coefficient in low-temperature warm inflation
• A First Principles Warm Inflation Model that Solves the Cosmological Horizon/Flatness Problems
• Power spectrum for inflation models with quantum and thermal noises
• Warm inflation as a way out of the swampland
• Density fluctuations from warm inflation
• Shear viscous effects on the primordial power spectrum from warm inflation
• Warm inflation dissipative effects: predictions and constraints from the Planck data
• Minimal Warm Inflation
• Towards a reliable effective field theory of inflation
• Dark Energy Radiation
• Runaway potentials in warm inflation satisfying the swampland conjectures

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• Thermal Gravitons from Warm Inflation
• Defying eternal inflation in warm inflation with a negative running