Probing cosmological fields with gravitational wave oscillations

Understand

Gravitational wave (GW) oscillations occur whenever there are additional tensor modes interacting with the perturbations of the metric coupled to matter.

• These extra modes can arise from new spin-2 fields (as in e.g.
• bigravity theories) or from non-trivial realisations of the cosmological principle induced by background vector fields with internal symmetries (e.g.
• Yang-Mills, gaugids or multi-Proca).