  Disorder-free localization in translation-invariant gauge theories presents a
counterintuitive yet powerful framework of ergodicity breaking in quantum
many-body physics. The fragility of this phenomenon in the presence of
gauge-breaking errors has recently been addressed, but no scheme has been able
to reliably stabilize disorder-free localization through all accessible
evolution times while preserving the disorder-free property. Here, we introduce
the concept of \textit{Stark gauge protection}, which entails a linear sum in
gauge-symmetry local (pseudo)generators weighted by a Stark potential. Using
exact diagonalization and Krylov-based methods, we show how this scheme can
stabilize or even enhance disorder-free localization against gauge-breaking
errors in $\mathrm{U}(1)$ and $\mathbb{Z}_2$ gauge theories up to all
accessible evolution times, without inducing \textit{bona fide} Stark many-body
localization. We show through a Magnus expansion that the dynamics under Stark
gauge protection is described by an effective Hamiltonian where gauge-breaking
terms are suppressed locally by the protection strength and additionally by the
matter site index, which we argue is the main reason behind stabilizing the
localization up to all accessible times. Our scheme is readily feasible in
modern ultracold-atom experiments and Rydberg-atom setups with optical
tweezers.
