Speaker
Description
The imprint of inflation on primordial gravitational waves remains one of the most promising probes of the early Universe, offering a potential observational window into physics at otherwise inaccessible energy scales. In this study, the impact of non-trivial inflationary potentials on the primordial tensor power spectrum is investigated within the framework of standard single-field inflation in General Relativity (GR).
A class of models based on the Double-Sine-Gordon (DSG) potential is considered,
\begin{equation}
V(\phi) = \alpha \cos(N\phi) + \beta \cos(2N\phi),
\end{equation}
where $\phi$ denotes the inflaton field, while $\alpha$, $\beta$, and $N$ are free parameters controlling the amplitude of the harmonic contributions and the characteristic frequency of the oscillatory structure. In this model, an intrinsic oscillatory structure extends conventional cosine-based scenarios. Employing the slow-roll approximation, the background dynamics are analyzed, and the resulting tensor power spectrum is computed as a function of the comoving wavenumber (k).
The DSG potential is found to induce small but systematic deviations from scale invariance, manifesting as controlled oscillatory modulations in the tensor spectrum. The amplitude and frequency of these features are directly governed by the model parameters, establishing a connection between the inflationary potential and observable quantities.
Such oscillatory signatures may leave imprints in the stochastic gravitational wave background, potentially within the sensitivity range of future detectors such as LISA and the Einstein Telescope, as well as Cosmic Microwave Background (CMB) polarization missions. These results suggest that even minimal extensions of the inflationary potential may lead to potentially distinguishable observational signatures, providing a possible avenue for probing the structure of the inflationary landscape.