https://doi.org/10.1140/epjc/s10052-024-12436-y
Regular Article - Theoretical Physics
Anisotropic power-law inflation for models of non-canonical scalar fields non-minimally coupled to a two-form field
1
Phenikaa Institute for Advanced Study, Phenikaa University, 12116, Hanoi, Vietnam
2
Faculty of Basic Sciences, Phenikaa University, 12116, Hanoi, Vietnam
3
Institute of Physics, National Yang Ming Chiao Tung University, 30010, Hsin Chu, Taiwan
c
tuan.doquoc@phenikaa-uni.edu.vn
Received:
11
September
2023
Accepted:
11
January
2024
Published online:
31
January
2024
In this paper, we investigate the validity of the so-called cosmic no-hair conjecture in the framework of anisotropic inflation models of non-canonical scalar fields non-minimally coupled to a two-form field. In particular, we focus on two typical k-inflation and Dirac–Born–Infeld inflation models, in which we find a set of exact anisotropic power-law inflationary solutions. Interestingly, these solutions are shown to be stable and attractive during an inflationary phase using the dynamical system analysis. The obtained results indicate that the non-minimal coupling between the scalar and two-form fields acts as a non-trivial source of generating stable spatial anisotropies during the inflationary phase and therefore violates the prediction of the cosmic no-hair conjecture, even when the scalar field is of non-canonical forms. In connection with the Planck 2018 data, tensor-to-scalar ratios of these anisotropic solutions are investigated. As a result, it appears that the tensor-to-scalar ratio of the anisotropic power-law inflationary solution of k-inflation model turns out to be more highly consistent with the Planck 2018 data than that of Dirac-Born-Infeld model.
© The Author(s) 2024
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