A new proof identifies a 'safe zone' in quantum systems where the 'spooky' phenomenon of entanglement is physically impossible.
April 1, 2026
Original Paper
Separable neighbourhood of identity in C$^{\ast}$-algebras
arXiv · 2603.29556
The Takeaway
While entanglement is often seen as an unavoidable part of the quantum world, researchers proved there is always a guaranteed 'neighborhood' of normal, classical behavior around a system's most random state. This resolves a major conjecture and helps define the exact physical boundaries where quantum weirdness must end.
From the abstract
We study the structure of separable elements in bipartite C$^{\ast}$-algebras, focusing on the existence and size of a separable neighbourhood around the identity element. While this phenomenon is well understood in the finite-dimensional setting, its extension to general C$^{\ast}$-algebras presents additional challenges. We show that the problem of determining such a neighbourhood can be reduced to estimating the completely bounded norm of contractive positive maps. This approach allows us to