De sitter relativity: a natural scenario for an evolving Lambda

In de Sitter special relativity, spacetime translations are replaced by a combination of translations and proper conformal transformations. As a consequence, the energy-momentum current is replaced by a combination of ordinary energy-momentum and proper conformal currents. Whereas the ordinary energy-momentumtensor remains to be a dynamic source of the spacetime curvature, the proper conformal current appears as a kinematic source of I >. The de Sitter special relativity, therefore, allows for a new interpretation of dark energy as an entity encoded in the kinematic group of spacetime. Furthermore, since ordinary energy is allowed to transform into dark energy and vice versa, it provides a natural scenario for an evolving cosmological term. A qualitative discussion on how a I >-evolving universe would behave is presented.