Torsional Carroll Gravity

The ultrarelativistic (Carrollian) regime of gravity has recently emerged as a fertile framework for exploring holography, non-Lorentzian symmetries, and geometric limit of general relativity. In this Letter, we establish the presence of a nonvanishing torsion within three-dimensional Carrollian gravity by constructing the Carrollian Mielke-Baekler (C-MB) gravity theory in its Chern-Simons formulation, obtained as the ultrarelativistic limit of the relativistic Mielke-Baekler model. The resulting C-MB theory features nonzero temporal torsion and curvature, together with spatial curvature, providing the most general three-dimensional Carrollian gravity model with these properties. Temporal torsion affects nonaffinity of null generators and boundary dynamics. Several known ultrarelativistic gravity theories arise as particular limits of this framework, highlighting its unifying character.