The Ettih Architecture II: Testing Pulse Ordering and Quasiperiodic Dynamical Decoupling — Resolving Two Open Questions from Paper I

Paper I established a single-atom baseline for room-temperature Rydberg electromagnetically induced transparency (EIT) in thermal rubidium vapor and reported two unresolved numerical questions: whether genuine counter-intuitive pulse ordering improves Stark-chirped rapid adiabatic passage (SCRAP)-assisted transfer, and whether Fibonacci-modulated control improves coherence beyond merely broadening the drive spectrum. We address both directly. Using the same three- level ladder Hamiltonian, decay rates, and 10 ns pulse window as the prior preprint, we find that counter-intuitive ordering within the fixed window degrades transfer efficiency to near zero (0.02%) rather than improving it, and we diagnose the failure as a short-window boundary-condition problem rather than a failure of the STIRAP mechanism itself. We then model a stored |1⟩–|3⟩coherence subject to Ornstein–Uhlenbeck dephasing noise and compare periodic and Fibonacci-timed π-phase- flip sequences using direct time-domain Monte Carlo simulation. In the regime where the noise correlation time matches the inter-pulse spacing, Fibonacci timing yields a 2.4×coherence advantage over periodic decoupling (0.0266 vs. 0.0110), while periodic decoupling outperforms Fibonacci in the quasi-static noise limit (0.964 vs. 0.785). We report both the negative and positive results transparently, without tuning parameters to force a preferred outcome.