The fate of Quasi-Exponential inflation in the light of ACT-DR6

Abstract

We have revisited quasi-exponential model of inflation in the light of recent ACT-DR6 and Planck data along with latest constraint on the amplitude of primordial gravitational waves. For our analysis we have followed Mukhanov approach for inflationary equation-of-state employing Hamilton-Jacobi formulation. We find that the model is capable of mimicking latest Planck results by providing excellent fit to scalar spectral index and its running. Not only that, amount of primordial gravitational waves is also within the present observational bound, $r<0.032$. In addition to that, when the combination of ACT-DR6 and Planck joint with BICEP/Keck 2018 data is taken into account inflationary predictions from quasi-exponential model are in excellent agreement. The model also yields sublime fit to the result of joint analysis of ACT-DR6, Planck joint with BICEP/Keck 2018 and DESI-Y1 data. The futuristic CMB missions LiteBIRD, Simons Observatory and CMB-S4 are promising to detect primordial gravitational waves if $r\ge 0.003$. We have also forecasted inflationary predictions from quasi-exponential model of inflation assuming the sensitivities of LiteBIRD, Simons Observatory and CMB-S4 along with combination of LiteBIRD and CMB-S4. We found that in each case quasi-exponential inflation may render excellent fit provided $r\ge 10^{-2}$. However, non-detection of primordial gravitational waves by LiteBIRD, Simons Observatory and CMB-S4 will potentially rule out quasi-exponential model.

Accepted For Publication in EPJC

References in corpus (9)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
• Improved limits on the tensor-to-scalar ratio using BICEP and Planck
• DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars
• Cosmological parameters derived from the final (PR4) Planck data release
• CMB-S4: Iterative Internal Delensing and $r$ Constraints
• An Inflationary Equation of State

Cited by in corpus (2)

• Confronting Inflation and Reheating with Observations: Improved Predictions
• Confronting Mukhanov Parametrization of Inflationary Equation-of-State with ACT-DR6