Dynamical interface above a hard wall and reflected SPDE on the half-line

We consider a dynamical random interface on the infinite lattice $\mathbb{N}$ evolving according to a “corner flip” dynamic above a hard wall, with an additional pinning at the origin. We study the stationary fluctuations under a diffusive scaling and prove convergence in law towards the solution of an SPDE of Nualart-Pardoux’s type, namely the Reflected Stochastic Heat Equation on the half-line. We also obtain that the law of the 3-dimensional Bessel process is an invariant measure for this SPDE.