Tachyon Mimetic Inflation as an Instabilities-Free Model

Abstract

We consider the mimetic tachyon model in the Lagrange multiplier approach. We study both the linear and non-linear perturbations and find the perturbation and non-gaussianity parameters in this setup. By adopting two types of the scale factor as the power-law ($a=a_0{t}^n$) and intermediate ($a=a_0\exp (b{t}^{\beta })$) scale factors, we perform a numerical analysis on the model which is based on Planck2018 TT, TE, EE+lowE+lensing +BAO +BK14 and Planck2018 TTT, EEE, TTE and EET data sets. We show that the mimetic tachyon model with both the power-law and intermediate scale factors, in some ranges of its parameter space is instabilities-free and observationally viable. The power-law mimetic tachyon model with $26.3<n<33.0$ and the intermediate mimetic tachyon model with $0.116<\beta <0.130$ are consistent with observational data and free of the ghost and gradient instabilities.

14 pages, 15 figures, 6 tables

References in corpus (21)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• The Effective Field Theory of Inflation
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Primordial Non-Gaussianities from Inflation Models
• Cosmology with Mimetic Matter
• Mimetic $F(R)$ gravity: inflation, dark energy and bounce
• Planck 2018 results. IX. Constraints on primordial non-Gaussianity
• Inflationary universe from perfect fluid and $F(R)$ gravity and its comparison with observational data
• Dynamics of Logamediate Inflation
• Primordial non-Gaussianities in general modified gravitational models of inflation
• Causality and the speed of sound
• Perturbation, Non-Gaussianity and Reheating in a GB-$\alpha$-Attractor Model
• Extended mimetic gravity: Hamiltonian analysis and gradient instabilities
• Imperfect Dark Matter
• Viable Mimetic Completion of Unified Inflation-Dark Energy Evolution in Modified Gravity
• Hamiltonian Formulation of Mimetic Gravity
• Modified Dust and the Small Scale Crisis in CDM
• Gauss-Bonnet Inflation after Planck2018
• Hamiltonian analysis of mimetic scalar gravity revisited
• Higher order derivative coupling to gravity and its cosmological implications
• Mimetic DBI Inflation in Confrontation with Planck2018 data

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• Some Aspects of the Tachyon Inflation with Superpotential in Confrontation with Planck2018 Data
• Viable Intermediate Inflation in the Mimetic DBI Model
• A Tachyon Field around the Black Hole