Fakultäten » Mathematischnaturwissenschaftliche Fakultät » PhysikInstitut » Prof. Dr. Philippe Jetzer » Naef
Title / Titel  Gravitational radiation in f(R) gravity  

Abstract (PDF, 14 KB)  
Summary / Zusammenfassung  Since the discovery of the PSR 1913+16 system by Hulse and Taylor in 1974, binary pulsars have become an important laboratory for testing gravity theories. Among such theories we consider so–called f(R) theories, for which the Einstein–Hilbert action of GR is replaced by a nonlinear function f of the Ricci scalar R. For such theories, still an open problem is the calculation of the energy loss of a binary pulsar system by radiation of gravitational waves in the linearised theory. We investigated the gravitational radiation emitted by an isolated system for gravity theories with Lagrange density f(R) = R+aR2. As a formal result we obtained leading order corrections to the quadrupole formula in General Relativity. We made use of the analogy of f(R) theories with scalartensor theories, which in contrast to General Relativity feature an additional scalar degree of freedom. Unlike General Relativity, where the leading order gravitational radiation is produced by quadrupole moments, the additional degree of freedom predicts gravitational radiation of all multipoles, in particular monopoles and dipoles, as this is the case for the most alternative gravity theories known today. An application to a hypothetical binary pulsar moving in a circular orbit yields a limit by constraining the dipole power to account at most for 1% of the quadrupole power as predicted by General Relativity. 

Publications / Publikationen  Phys. Rev. D., Volume 84, (2011), 024027  
Project leadership and contacts / Projektleitung und Kontakte 


Funding source(s) / Unterstützt durch 
SNF (Personen und Projektförderung) 

Duration of Project / Projektdauer  Jul 2010 to Jun 2011 