Narrow Results

In this paper, we study various cosmological parameters and quantities in scalar–tensor gravity (STG) from inflation and swampland conjecture. Therefore, by selecting different models as power-law, exponential, and logarithmic in the framework of scalar–tensor theory, we obtain potential, tensor-to-scalar ratio, and the scalar spectral index. Next, we examine new constraints and compare the corresponding results with the latest observable data. Here, we take advantage of the obtained results and determine the compatibility or incompatibility of the corresponding model with the swampland conjectures.

In this paper, a new form of dark energy, known as Tsallis holographic dark energy (THDE), with IR cutoff as Hubble horizon proposed by Tavayef et al. Tsallis holographic dark energy, Phys. Lett. B781 (2018) 195 has been explored in Bianchi-III model with the matter. By taking the time subordinate deceleration parameter, the solution of Einstein’s field equation is found. The Universe evolution from earlier decelerated to the current accelerated phase is exhibited by the deceleration parameter acquired in the THDE model. It can be seen that the derived THDE model is related to an accelerating Universe with quintessence ($\omega \ge -1$). The squared sound speed $v_s^2$ also suggests that the THDE model is classically stable at present. In addition, the quintessence phase of the THDE model is analyzed with swampland conjecture to reformulate the accelerating expansion of the Universe.