Approximate null-controllability of discrete heat equations with potentials on lattices

TL;DR

This paper establishes approximate null-controllability for semi-discrete heat equations with potentials on lattices, using spectral inequalities and control methods, with results applicable to bounded and polynomial growth potentials.

Contribution

It extends spectral and controllability analysis to lattice heat equations with potentials, providing explicit estimates and handling polynomial growth cases.

Findings

Spectral inequalities for discrete Schrödinger operators on lattices.

Quantitative controllability results with explicit potential dependence.

Extension of Carleman techniques to full-space lattice setting.

Abstract

We investigate approximate null-controllability for semi-discrete heat equations on the lattice $h\mathbb{Z}^d$ with a potential. By establishing spectral inequalities for the discrete Schr{\"o}dinger operator $P_h = -\Delta_h + V$ on equidistributed sets, we derive observability estimates via the Lebeau-Robbiano method and the Hilbert Uniqueness Method. For bounded potentials, we obtain quantitative controllability results with explicit dependence on the potential and show near optimality of the geometric condition on the observation set. We also treat polynomial growth potentials, for which similar properties hold with weaker control cost estimates. These results extend discrete Carleman techniques to the full-space lattice setting and provide new spectral estimates for discrete Schr{\"o}dinger operators.