Bounded Decoherence: Testable Predictions from Constrained Quantum State Reduction

We derive a testable consequence of the hypothesis that quantum decoherence is subject to a global compression bound. Starting from the bounded compression condition, we show that simultaneous decoherence across multiple channels of a quantum system must satisfy a trade-off relation: the weighted sum of individual decoherence rates is bounded by a maximum determined by the system's energy scale and the quantum channel capacity of the system-environment coupling. We derive this bound from two independent physical principles: the finite quantum channel capacity of the environment as an information sink, and the thermodynamic cost of irreversible decoherence via the Landauer principle. For multi-qubit systems, we predict that the decoherence rate of maximally entangled (GHZ) states saturates for sufficiently large qubit number N, deviating from the linear scaling predicted by standard Lindblad theory. We identify the transition regime between weak and strong system-environment coupling as the natural domain where the bound becomes experimentally accessible, and propose concrete protocols using superconducting qubits, trapped ions, and mesoscopic systems. The predictions are falsifiable and independent of any specific interpretive framework for quantum mechanics.