https://doi.org/10.1140/epjc/s10052-024-13232-4
Regular Article –Theoretical Physics
Carroll geodesics
1
Perimeter Institute for Theoretical Physics, 31 Caroline St. N., N2L 2Y5, Waterloo, ON, Canada
2
Institute for Theoretical Physics, TU Wien, Wiedner Hauptstrasse 8–10/136, 1040, Vienna, Austria
Received:
4
April
2024
Accepted:
11
August
2024
Published online:
16
September
2024
Using effective field theory methods, we derive the Carrollian analog of the geodesic action. We find that it contains both “electric” and “magnetic” contributions that are in general coupled to each other. The equations of motion descending from this action are the Carrollian pendant of geodesics, allowing surprisingly rich dynamics. As an example, we derive Carrollian geodesics on a Carroll–Schwarzschild background and discover an effective potential similar to the one appearing in geodesics on Schwarzschild backgrounds. However, the Newton term in the potential turns out to depend on the Carroll particle’s energy. As a consequence, there is only one circular orbit localized at the Carroll extremal surface, and this orbit is unstable. For large impact parameters, the deflection angle is half the value of the general relativistic light-bending result. For impact parameters slightly bigger than the Schwarzschild radius, orbits wind around the Carroll extremal surface. For small impact parameters, geodesics get reflected by the Carroll black hole, which acts as a perfect mirror.
© The Author(s) 2024
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