Fuchuan Wei, Zi-Wen Liu (Mar 07 2025).

Abstract: Understanding nonstabilizerness (aka quantum magic) in many-body quantum systems, particularly its interplay with entanglement, represents an important quest in quantum computation and many-body physics. Drawing natural motivations from the study of quantum phases of matter and entanglement, we systematically investigate the notion of long-range magic (LRM), defined as nonstabilizerness that cannot be erased by constant-depth local circuits. By establishing connections to the Bravyi--König theorem concerning the limitation of fault-tolerant logical gates, we show that certain families of topological stabilizer code states exhibit LRM. Then, we show that all ground states of topological orders that cannot be realized by topological stabilizer codes, such as Fibonacci topological order, exhibit LRM, which can be viewed as a no lowest-energy trivial magic'' result. Building on our considerations of LRM, we discuss the classicality of short-range magic from e.g.~preparation and learning perspectives, and put forward a no low-energy trivial magic'' (NLTM) conjecture that has key motivation in the quantum PCP context. We also connect two-point correlations with LRM, demonstrating certain LRM state families by correlation properties. Most of our proof techniques do not depend on geometric locality and can potentially be extended to systems with general connectivity. Our study leverages and sheds new light on the interactions between quantum resources, coding and fault tolerance theory, complexity theory, and many-body physics.

Arxiv: https://arxiv.org/abs/2503.04566