Renormalization-group running cosmologies and the generalized second law

We explore some thermodynamical consequences of accelerated universes driven by a running cosmological constant (CC) from the renormalization group (RG). Application of the generalized second law (GSL) of gravitational thermodynamics to a framework where the running of the CC goes at the expense of energy transfer between vacuum and matter, strongly restricts the mass spectrum of a (hypothetical) theory controlling the CC running. We find that quantum effects driving the running of the CC should be dominated by a trans-Planckian mass field, in marked contrast with the GUT-scale upper mass bound obtained by analyzing density perturbations for the running CC. The model shows compliance with the holographic principle.