title: Gravitational Waves from Isolated Systems: Surprising Consequences of a Positive Cosmological Constant.
abstract: There is a deep tension between the well-developed theory of gravitational waves from isolated systems and the presence of a positive cosmological constant Λ, however tiny. In particular a generalization of Einstein's 1918 quadrupole formula that would allow a positive Λ is not yet available. We first explain the principal difficulties and then show that it is possible to overcome them in the weak field limit. These results also provide concrete hints for constructing the Λ>0 generalization of the Bondi-Sachs framework for full, nonlinear general relativity.
authors.affiliation: Institute for Gravitation and the Cosmos & Physics Department, Penn State, University Park, Pennsylvania 16802, USA.
authors.forename: Abhay
authors.initials: A
authors.lastname: Ashtekar
authors.affiliation: Institute for Gravitation and the Cosmos & Physics Department, Penn State, University Park, Pennsylvania 16802, USA.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Bonga
authors.affiliation: Institute for Gravitation and the Cosmos & Physics Department, Penn State, University Park, Pennsylvania 16802, USA.
authors.forename: Aruna
authors.initials: A
authors.lastname: Kesavan