Abstract
The latest Planck results show a power deficit in the temperature anisotropies near in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary -cold-dark-matter () scenario. In this paper we consider a string theory inspired inflationary model (axion monodromy inflation) with a step-like modulation in the potential which gives rise to observable signatures in the primordial perturbations. One interesting phenomenon is that the primordial scalar modes experience a sudden suppression at a critical scale when the modulation occurs. By fitting to the CMB data, we find that the model can nicely explain the power deficit anomaly as well as predict specific patterns in the temperature-polarization correlation and polarization autocorrelation spectra. Though the significance of the result is not sufficient to claim a detection, our analysis reveals that fundamental physics at extremely high energy scales, namely, some effects inspired by string theory, may be observationally testable in forthcoming cosmological experiments.
- Received 28 July 2015
DOI:https://doi.org/10.1103/PhysRevD.92.121303
© 2015 American Physical Society