  A recent study established a correspondence between the Generalized
Uncertainty Principle (GUP) and Modified theories of gravity, particularly
Stelle gravity. We investigate the consequences of this correspondence for
inflation and cosmological observables by evaluating the power spectrum of the
scalar and tensor perturbations using two distinct methods. First, we employ
PLANCK observations to determine the GUP parameter $\gamma_0$. Then, we use the
value of $\gamma_0$ to investigate the implications of quantum gravity on the
power spectrum of primordial gravitational waves and their possible
detectability in the next-generation detectors, like Einstein Telescope and
Cosmic explorer.
