On a physical description and origin of the cosmological constant

Abstract

In this paper we use and extend the results present in \cite{1,2,3,4} and in particular in \cite{4} to obtain a statistical description of the cosmological constant in a cosmological de Sitter universe in terms of massless excitations with Planckian effects. First of all, we show that at a classical level, the cosmological constant $\Lambda>0$ can be obtained only for $T\rightarrow 0$. Similarly to the black hole case, when quantum effects are taken into account, a representation for $\Lambda$ is possible in terms of massless excitations, provided that quantum corrections to the Misner-Sharp mass are considered. Moreover, thanks to quantum fluctuations, an effective cosmological constant arises depending on the physical scale under consideration, thus representing a possible solution to the cosmological constant problem without introducing a quintessence field. The smalness of the actual value for $\Lambda$ can be due to the existence of a quantum decoherence scale above the Planck length such that the spacetime evolves as a pure de Sitter universe with a small averaged cosmological constant frozen in the lowest energy state.