Speaker
Description
The application of the Horndeski theory in late-time cosmology is strongly limited by the strict coincidence of the propagation speeds of gravitational and electromagnetic waves. This restriction assumes that a photon with minimal coupling is not modified even at scales at which General Relativity (GR) may need modification. We have shown that the four-dimensional Galileon, obtained as a result of the Kaluza-Klein compactification of its five-dimensional version, can be considered as a natural modification of GR and electromagnetism. In this theory, gravitational waves propagate at the speed of light, which means that there is no need for fine-tuning the Galileon potential. This allows for a wider range of theories than was previously considered.
