Asymptotics with a positive cosmological constant II: Illustration with linear fields on de Sitter space-time

The framework that allows the study of isolated systems is well-developed for space-times with a vanishing cosmological constant $\Lambda$ and it lies at the foundation of research in diverse areas in gravitational physics. However, the standard extension of this framework to space-times with a positive $\Lambda$ fails for non-stationary space-times. Here, I will outline a new proposal that does allow the study of isolated systems with $\Lambda>0$ in a physically meaningful manner and has the additional benefit of providing a natural comparison with asymptotically flat space-times. This proposal is illustrated by calculations with test fields in de Sitter space-time. The results are contrasted with test fields in Minkowski space-time. It is expected that the results for test fields will share many features with gravitating systems. The linear analysis provides a first step to study the errors one makes by assuming $\Lambda=0$ when studying general relativistic gravitating systems.