https://doi.org/10.1140/epjc/s10052-025-14259-x
Regular Article - Theoretical Physics
Returning back to Mukhanov parametrization of inflationary equation of state
Netaji Nagar College For Women, 700092, Kolkata, West Bengal, India
Received:
21
December
2024
Accepted:
3
May
2025
Published online:
16
May
2025
We have re-examined Mukhanov parametrization for inflationary equation of state, 
, in the light of Planck 2018 results and latest bound of tensor-to-scalar ratio employing Hamilton–Jacobi formalism. We have found that the current observational values of scalar spectral index and tensor-to-scalar ratio can be used efficiently to constrain the model parameters. The recent bound of 
has been used to put an upper bound on one of the model parameter. Whereas 1-
bound of the scalar spectral index 
along with the upper bound of tensor-to-scalar ratio provided restriction on the other model parameter 
. These bounds however depend on the number of e-foldings still left before the end of inflation and whenever we can find appropriate values of the other model parameter 
so that the observational predictions are in tune with the latest available inflationary observables. We have further utilized the predictions from forthcoming CMB missions in the likes of CMB-S4 and LiteBIRD in order to obtain bounds on the model parameters. We find that detection of gravity waves would help us constrain the model parameters further. But in the absence of detection of primordial gravity wave signal by these CMB missions may rule out Mukhanov parametrization.
© The Author(s) 2025
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