Narrow Results

In order to solve the mystery of the accelerating and expanding universe model first, various dark energy candidates, such as Quintessence, Tachyon, k-essence, Phantom and DBI-essence, were investigated in detail in the $f(Q)$ modified symmetric teleparallel gravitation theory for homogeneous and isotropic FRLW universe model. The $f(Q)=a{Q}^n+b$ model is used to obtain solutions in $f(Q)$ theory. Also, the physical behaviors of some cosmological parameters such as pressure and density were studied. Dark energy candidates were analyzed for different values of n with various graphs.

In the present work we investigated the validity of the generalized second law (GSL) of thermodynamics in the presence of interaction between DBI-essence and other four candidates of dark energy, namely the modified Chaplygin gas, hessence, tachyonic field and new agegraphic dark energy. It has been observed that the GSL breaks down in the presence of the interactions. However, the event horizon remains to be an increasing function of time.

Motivated by the work of Nojiri et al., Phys. Lett. B797, 134829 (2019), the present study demonstrates inflation driven by holographic DBI-essence scalar field. Considering a simple correction due to the Ultraviolet cutoff, we have studied the slow-roll parameters. It has been observed that the role of the UV-cutoff is not negligible and in the limiting case of ${\mathrm{\Lambda }}_{\mathrm{\text{UV}}}\to \infty$ the inflationary model is characterized by Type-III singularity but can avoid Big-Rip singularity. Finally, it has been observed that the trajectories in $n_s-r$ are compatible with the observational bound found by Planck. It has been concluded that the tensor to scalar ratio for this model can explain the primordial fluctuation in the early universe as well. However, under the purview of $f(T)$ inflation, although the DBI-essence scalar field can explain primordial fluctuation, the holographic DBI-essence scalar field does not lead to $n_s-r$ trajectory satisfying the Planck’s observational bound.