In the framework of Friedmann-Lemaitre-Robertson-Walker cosmology modified by entropic issues, the sign change of the inhomogeneous term associated with the nonconservation energy equation for cosmic fluid is discussed; specifically, this is a bare/effective study of the equation of state for this fluid through a bare (ω)/effective (ωeff) description. In the bare case, where there is a nonconserved equation of state, the change in the sign of the inhomogeneous term at different times of the cosmic evolution is described. By redefining the adiabatic ω-parameter, the usual scheme for cosmic evolution can be recovered. In the effective case, if evolution is driven by dust or the cosmological constant, the universe evolves towards thermal equilibrium. However, by incorporating a quantum correction, only the cosmological constant can lead to thermal equilibrium. This correction avoids the future singularity that is present when it is not incorporated.
- Modified gravity