Massive, massless and ghost modes of gravitational waves from higher-order gravity

Charalampos Bogdanos , Salvatore Capozziello (1) , Mariafelicia De Laurentis (1) , Savvas Nesseris (2)

1 Dipartimento di Scienze Fisiche [Naples]
2 NBI - Niels Bohr Institute [Copenhagen]

We linearize the field equations for higher order theories that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes. Then, we investigate the possible detectability of such additional polarization modes of a stochastic gravitational wave by ground-based and space interferometric detectors. Finally, we extend the formalism of the cross-correlation analysis, including the additional polarization modes, and calculate the detectable energy density of the spectrum for a stochastic background of the relic gravity waves that corresponds to our model. For the situation considered here, we find that these massive modes are certainly of interest for direct detection by the LISA experiment.

Mots clés: gravitational waves; alternative theories of gravity; cosmology

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Charalampos Bogdanos, Salvatore Capozziello, Mariafelicia De Laurentis, Savvas Nesseris. Massive, massless and ghost modes of gravitational waves from higher-order gravity. Astroparticle Physics, 2010, 34 (4), pp.236. ⟨10.1016/j.astropartphys.2010.08.001⟩. ⟨hal-00679603⟩