Investigation of the magnetized string distribution in the Marder universe with the cosmological term in f(R,T) theory

In this study, we first obtained the cosmological term naturally in the Einstein–Hilbert type effect for the [Formula: see text] theory, then we discussed the magnetized string matter in the Marder universe, later the matter Lagrangian is not equivalent to string dust and we calculated independently for the string dust and the electromagnetic field, and added the magnetized string together. Finally, we studied the physical and geometric structure of the universe, limiting our results to some astrophysical observation data.

Various dark energy models with time-varying G and Λ in f(R, T) gravitation theory

In this research, we have investigated tachyon and [Formula: see text]-essence dark energy (DE) candidates with varying [Formula: see text] and [Formula: see text] for Marder universe in [Formula: see text] gravitation theory [Harko et al., Phys. Rev. D 84, 024020 (2011)]. Here, [Formula: see text] is the arbitrary function of Ricci scalar ([Formula: see text]) and the trace of [Formula: see text]. To solve [Formula: see text] gravity field equations, three different approximations have been used such as cosmological term, equation of state (EoS) parameter and the anisotropy feature of Marder universe. Also, we have discussed some physical results with various graphics.