Laboratory-Constrained Coherence Dynamics and a Pre-Data Prediction for DESI Y3

We present a laboratory-constrained phenomenological framework linking controlled quantum coherence experiments to large-scale cosmological observables. Using experimental results from superconducting qubits subjected to structured low-frequency toroidal magnetic fields, we define a dimensionless coherence proxy, κ_lab = 0.728 ± 0.020, which captures both temporal decoherence suppression and spatial field uniformity. This observable is derived directly from measured enhancements in qubit relaxation time (T1), without modification to materials or circuit design. We then introduce a calibrated laboratory-to-cosmology bridge, mapping κ_lab into an effective coupling parameter within a coherence-driven cosmological framework. This mapping enables a quantitative pre-data prediction for an environmental modulation of the Hubble expansion rate:ΔH0/H0 = 0.73+0.21-0.18%,for the benchmark regime m_φ ~ H0 and α = 1. The key contribution of this work is not the assumption of a confirmed cross-scale mechanism, but the construction of a transparent and falsifiable bridge between a laboratory-measured coherence observable and a cosmological testable quantity. The prediction lies within the sensitivity range of DESI Year 3, enabling a clear binary test: • Detection of a ~0.5–1.0% environmental step supports the viability of scale-bridging coherence dynamics.• A null result constrains the phenomenological bridge while preserving the laboratory result as an independent demonstration of environmental coherence engineering. This approach establishes a new paradigm in which controlled quantum systems can serve as quantitative anchors for testing phenomenological extensions of large-scale physics, connecting laboratory coherence and cosmological expansion in a falsifiable framework.