Symmetry packaging II: Packaged subspaces, packaged entanglement, and classification

Symmetry packaging is the phenomenon whereby, upon particle creation, all the internal quantum numbers (IQNs) become locked into a single irreducible representation (irrep) block of the gauge group, as required by locality and gauge invariance. The resulting packaged quantum states exhibit characteristic symmetry constraints and entanglement patterns. We develop a group-theoretic framework to describe the symmetry packaging for a variety of concrete symmetries and to classify the corresponding packaged states:

(1) We prove that for any finite or compact group G, there exist G-associated packaged subspaces, in which every vector is automatically a packaged state. In particular, in multi-particle systems, any nontrivial representation of G induces inseparable packaged entanglement that locks together all IQNs.

(2) We apply this framework to symmetry packaging in finite groups (cyclic group $Z_N$, charge conjugation C, fermion parity, parity P, time reversal T, and dihedral groups), compact groups ($U\left(1\right)$, $\mathrm{SU}\left(N\right)$, $\mathrm{SU}\left(2\right)$, and $\mathrm{SU}\left(3\right)$), p-form symmetries, and hybrid symmetries. In each case, gauge invariance and superselection rules forbid the factorization of the resulting states. We illustrate how Bell-type packaged entangled states, color confinement, and hybrid gauge-invariant configurations all arise naturally. These results yield a complete classification of packaged quantum states.

(3) Finally, we extend the packaging principle to incorporate full spacetime symmetry and hybrid systems of local, global, and Lorentz/Poincaré charges.

Our approach unifies tools from group theory, gauge theory, and topological classification. These results may be useful for potential applications in high energy physics, quantum field theory, and quantum technologies.