Anomalous τ-Phase Correlated Quantum Coherence in Superconducting Qubits: Evidence for Non-Markovian Memory at τ0 = 46 μs

We report a statistically significant anomaly in quantum coherence measurements from 580 IBM Quantum jobs: Bell state fidelity varies periodically with job execution time modulo a characteristic period τ0 = 46 μs. Jobs executed at 'τ-aligned' phases show 1.81x higher mean fidelity than anti-aligned phases (p < 10^-14, Cohen's d = 1.65). This effect cannot be explained by standard Markovian decoherence. We present a phenomenological Lagrangian incorporating a non-Markovian memory field that predicts F(T) = F0 e^(-Γ T) (1 + ε cos(ω_τ T - θ_lock)), consistent with observations. Bayesian model comparison yields strong evidence (BF = 28) for the oscillatory model over exponential decay.