Gravitating Meron-like topological solitons in massive Yang-Mills theory and the Einstein-Skyrme model
We show that gravitating Merons in $D$-dimensional massive Yang-Mills theory can be mapped to solutions of the Einstein-Skyrme model. The identification of the solutions relies on the fact that, when considering the Meron ansatz for the gauge connection $A=λU^{-1}dU$, the massive Yang-Mills equations reduce to the Skyrme equations for the corresponding group element $U$. In the same way, the energy-momentum tensors of both theories can be identified and therefore lead to the same Einstein equations. Subsequently, we focus on the $SU(2)$ case and show that introducing a mass for the Yang-Mills field restricts Merons to live on geometries given by the direct product of $S^3$ (or $S^2$) and Lorentzian manifolds with constant Ricci scalar. We construct explicit examples for $D=4$ and $D=5$. Finally, we comment on possible generalisations.