Gravity and $T\bar{T}$ flows in higher dimensions

Abstract: We study systems in arbitrary space-time dimensions where matter, deformed by $\mathrm{T}\bar{\mathrm{T}}$-like irrelevant operators, is coupled to gravity in the Palatini formalism. The dynamically equivalent perspective is investigated, wherein the deformation transitions from the matter action to the gravitational one or vice versa. This alternative viewpoint leads to the emergence of Ricci-based gravity theories, thus providing a high-dimensional generalisation of the well-known equivalence between two-dimensional $\mathrm{T}\bar{\mathrm{T}}$ deformations and coupling to Jackiw-Teitelboim gravity. This dynamical equivalence is examined within the framework of the recently introduced Lagrangian flow equation, which notably led to the discovery of a direct link between Nambu-Goto theory and $\mathrm{T}\bar{\mathrm{T}}$ in $d=2$, as well as significant insights into nonlinear electrodynamics models in $d=4$. The investigation involves explicit examples in $d=4$ dimensions; it builds upon earlier research concerning the metric interpretation of $\mathrm{T}\bar{\mathrm{T}}$-like perturbations, incorporates and extends recent findings in the cosmology-related literature associated to the concept of reframing. We focus on scenarios where the resulting modified gravity theories manifest as Born-Infeld and Starobinsky types.