https://doi.org/10.1140/epjc/s10052-019-6578-x
Regular Article - Theoretical Physics
Warm DBI inflation with constant sound speed
1
Department of Physics, University of Kurdistan, Pasdaran Street, P.O. Box 66177-15175, Sanandaj, Iran
2
Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha, Iran
* e-mail: KKarami@uok.ac.ir
Received:
28
November
2018
Accepted:
5
January
2019
Published online:
28
January
2019
We study inflation with the Dirac–Born–Infeld (DBI) noncanonical scalar field in both the cold and warm scenarios. We consider the Anti-de Sitter warp factor 
for the DBI inflation and check viability of the quartic potential 
in light of the Planck 2015 observational results. In the cold DBI setting, we find that the prediction of this potential in the 
plane is in conflict with Planck 2015 TT, TE, EE + low P data. This motivates us to focus on the warm DBI inflation with constant sound speed. We conclude that in contrary to the case of cold scenario, the result of warm DBI model can be compatible with the 68% CL constraints of Planck 2015 TT, TE, EE + low P data in the intermediate and high dissipation regimes, whereas it fails to be observationally viable in the weak dissipation regime. Also, the prediction of this model for the running of the scalar spectral index 
is in good agreement with the constraint of Planck 2015 TT, TE, EE + low P data. Finally, we show that the warm DBI inflation can provide a reasonable solution to the swampland conjecture that challenges the de Sitter limit in the standard inflation.
© The Author(s), 2019
