Hierarchical Modulation of Gravitational-Wave Memory:

Paper Two Recent work on gravitational-wave communication has identified severe practical constraints on active signal generation, particularly energy consumption and bandwidth limitations (Wang & Akan, 2025). We propose a complementary paradigm shifting focus from transient propagation to permanent non-perturbative vacuum transitions encoded in gravitational-wave memory effects. Leveraging the PSZ triangle and celestial holography, we map the multi-dimensional degrees of freedom in GW memory — displacement, spin, helicity, and gyroscopic contributions — onto a formally motivated hierarchical modulation architecture. Treating the 2D celestial conformal field theory as a holographic storage medium, we establish a theoretical framework for a passive, ultra-long-lived communication channel inherently immune to electromagnetic interference and persistent across astrophysical timescales. Second paper in a three-part theoretical programme: Holographic Memory and Cyclic Cosmology.