Using entropy bounds to avoid the cosmological singularity and constrain cosmological particle production

In this work, we study the applications of entropy bounds in two toy cosmological models with particle production (annihilation), i.e., a radiation-dominated universe and a dust-dominated universe. We consider the co-moving volume and the volume covered by the particle horizon of a given observer as the thermodynamic systems satisfying entropy bounds. For the Bekenstein bound and the spherical entropy bound, it is found that the cosmological singularity can be avoided and cosmological particle production needs to be truncated in some special cases. Our study can be extended to other cosmological models with particle production.