Landscape Analysis of Simultaneous Blind Deconvolution and Phase Retrieval via Structured Low-Rank Tensor Recovery

This paper presents a geometric analysis of the simultaneous blind deconvolution and phase retrieval (BDPR) problem via a structured low-rank tensor recovery framework. Due to the highly complicated structure of the associated sensing tensor, directly characterizing its optimization landscape is intractable. To address this, we introduce a tensor sensing problem as a tractable surrogate that preserves the essential structural features of the target low-rank tensor while enabling rigorous theoretical analysis. As a first step toward understanding this surrogate model, we study the corresponding population risk, which captures key aspects of the underlying low-rank tensor structure. We characterize the global landscape of the population risk on the unit sphere and show that Riemannian gradient descent (RGD) converges linearly under mild conditions. We then extend the analysis to the tensor sensing problem, establishing local geometric properties, proving convergence guarantees for RGD, and quantifying robustness under measurement noise. Our theoretical results are further supported by extensive numerical experiments. These findings offer foundational insights into the optimization landscape of the structured low-rank tensor recovery problem, which equivalently characterizes the original BDPR problem, thereby providing principled guidance for solving the original BDPR problem.