A Probe into the Evolution of Primordial Perturbations in the f(T) Gravity Framework with Chaplygin Gas

This work is focused on studying the cosmology of variable modified Chaplygin gas (VMCG) in the framework of exponential and logarithmic f(T) theory. The equation of state (EoS) for VMCG in exponential and logarithmic f(T) gravity shows quintom behavior. Primordial perturbations were studied for VMCG in both exponential and logarithmic f(T) gravity, and it was observed that the potential increases with cosmic time t, and the scalar field decreases toward the minimum value of the potential. The squared speed of sound was positive, meaning that VMCG in both exponential and logarithmic f(T) gravity shows stability against small gravitational perturbations.