Entanglement principle and fractional Calderón problem for nonlocal parabolic operators
Ru-Yu Lai, Yi-Hsuan Lin, Lili Yan
TL;DR
This work addresses inverse problems for the nonlocal parabolic operator $\mathcal{H}_g^s=(\partial_t-\Delta_g)^s$ with $0<s<1$ by introducing an entanglement principle that decouples mixed fractional effects under a nonresonance condition on exponents. A modified entanglement principle is developed to overcome solution regularity barriers, enabling the analysis of poly-parabolic models $P_V=\sum_{k=1}^N b_k \mathcal{H}_g^{s_k}+V$ and the recovery of the time-dependent potential $V$ from exterior Dirichlet-to-Neumann data. The paper proves (i) an entanglement principle for fractional parabolic operators with $\alpha_k$ nonresonant, (ii) global uniqueness for $V$ from the DN map, and (iii) a Runge approximation framework to connect exterior data with interior information. The results extend nonlocal Calderón-type theory to time-dependent multi-term fractional parabolic models, providing a rigorous pathway for unique recovery of lower-order perturbations in practical, variable-coefficient settings through exterior measurements.
Abstract
We examine inverse problems for the variable-coefficient nonlocal parabolic operator $(\partial_t - Δ_g)^s$, where $0 < s < 1$. This article makes two primary contributions. First, we introduce a novel entanglement principle for these operators under suitable smoothness conditions. Second, we prove that lower-order perturbations can be uniquely determined from the associated Dirichlet-to-Neumann map using this principle. However, due to insufficient solution regularity, direct application of the entanglement principle to the inverse problem is not feasible. To address this, we derive a modified entanglement principle, enabling the effective resolution of related inverse problems.
