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

We have revisited quasi-exponential model of inflation in the light of recent ACT-DR6 and Planck-2018 data along with latest constraint on the amplitude of primordial gravity 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 Planck-2018 results by providing excellent fit to scalar spectral index and its running. Not only that, amount of primordial gravity waves is also in tune with the present observational bound, $r<0.032$. But, when constraints on scalar spectral index and tensor-to-scalar ratio are considered simultaneously quasi-exponential inflation fails to live up to the Planck-2018 result. However when the combination of ACT-DR6 and Planck-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-2018 and DESI-Y1 data. Further the constraint on primordial gravity waves from the futuristic CMB missions in the likes of LiteBIRD and CMB-S4 when combined with ACT-DR6, Planck-2018 and DESI-Y1 data renders a first-class match with the inflationary predictions from quasi-exponential model of inflation. However, non-detection of primordial gravity waves by LiteBIRD and CMB-S4 will potentially rule out quasi-exponential model.