# Entangled photons carry 17,000 invariants that engineers can now exploit - Date: 2026-03-21 - Category: Quantum Computing The interesting part of this quantum-light story is not the sci-fi language about a “hidden universe.” It is that a common lab workhorse—spontaneous parametric downconversion (SPDC)—may carry far richer structure than most teams have been using, with potential implications for how we engineer rob... ---