Renormalization of Field-Independent Term in the Cosmological Constant Problem

Renormalization group (RG) applications to cosmological problems often encounter difficulties in the interpretation of the field independent term in the effective potential. While this term is constant with respect to field variations, it generally depends on the RG scale k. Since the RG running could be associated with the temporal evolution of the Universe according to the identification $k sim 1/t$, one can treat the field independent constant, i.e., the $Lambda$ term in Einsteins equations as a running (scale-dependent) parameter. Its scale dependence can be described by nonperturbative RG, but it has a serious drawback, namely $k^4$ and $k^2$ terms appear in the RG flow in its high-energy (UV) limit which results in a rampant divergent behaviour. Here, we propose a subtraction method to handle this unphysical UV scaling and provides us a framework to build up a reliable solution to the cosmological constant problem.