Gravitational wave lensing beyond general relativity: Birefringence, echoes, and shadows

  title={Gravitational wave lensing beyond general relativity: Birefringence, echoes, and shadows},
  author={Jose Mar{\'i}a Ezquiaga and Miguel Zumalac'arregui},
  journal={Physical Review D},
Gravitational waves (GW), as light, are gravitationally lensed by intervening matter, deflecting their trajectories, delaying their arrival and occasionally producing multiple images. In theories beyond general relativity (GR), new gravitational degrees of freedom add an extra layer of complexity and richness to GW lensing. We develop a formalism to compute GW propagation beyond GR over general space-times, including kinetic interactions with new fields. Our framework relies on identifying the… 

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