Einstein--Skyrme Theory on a Planck-Scale Causal Lattice

We propose a UV-complete theory of gravity by placing the Einstein--Skyrme system on a Planck-scale causal lattice. The Skyrme field ($SU(2)$) provides a topological regulator via $\pi_3(SU(2))=\mathbb{Z}$, setting a cutoff $\Lambda_{\rm UV}=2\pi/\ell_{\rm Pl}$. The model passes solar-system tests via Vainshtein screening and predicts a chiral primordial gravitational-wave background peaking at $f=2.87\pm0.03\,\text{mHz}$ ($\Omega_{\rm GW} h^2 \sim 10^{-12}$), detectable by LISA. The tensor-tensor-tensor non-Gaussianity is enhanced, $f_{\rm NL}^{\rm GW} \sim \mathcal{O}(10)$.