Aravindan Vijayaraghaven (Northwestern) - Computing Linear Sections of Varieties: Quantum Entanglement, Tensor Decompositions and Beyond

We study the problem of finding elements in the intersection of an arbitrary conic variety (over reals or complex numbers) with a given linear subspace. This problem captures a rich family of algorithmic problems under different choices of the variety. The special case of the variety consisting of rank-1 matrices already has strong connections to central problems in different areas like quantum information theory and tensor decompositions.

Despite the worst-case NP-hardness of this problem, we give efficient algorithms that solve this problem for “typical” subspaces i.e., those chosen generically of a certain dimension, potentially with some generic elements of the variety contained in it, under some mild non-degeneracy assumptions on the variety. These also imply new algorithmic results for low-rank decomposition problems that go beyond tensor decompositions, and problems in quantum entanglement.

This is based on joint work with Nathaniel Johnston and Benjamin Lovitz.

Host: Alexander Razborov