Exploring the wonderland of Carrollian physics: Extreme gravity, spacetime horizons and supersonic fluids

Symmetries play an essential role in our understanding of the physical world. Central to this is the notion of space and time and the symmetries between them. According to Einstein’s celebrated theory of relativity, our world has Poincaré symmetry which mixes time and space. Galilean symmetry where time is absolute, as we experience in every day life, follows from this when considering the speed of light to be infinite. On the other hand, there is a much less studied limit in which we send the speed of light to zero, giving rise to Carroll symmetry.

For decades this limit of relativity has been considered a mere curiosity. However, it is becoming clear that Carrollian physics can provide new insights into a wide scope of physical phenomena, including strong gravity, cosmology and black hole physics. This project aims therefore to use Carroll symmetry as a novel organizing principle in studying extreme gravity and spacetime horizons. Moreover, replacing the speed of light by a Fermi-velocity or a sound velocity, there may be interesting applications of this approach in condensed matter systems. It is proposed that supersonic phenomena should then obey the constraints imposed by Carroll symmetry.