We present a derivation of quantum decoherence rates within a vacuum pressure gradient model of gravity, in which local vacuum density decreases near massive objects according to rhoᵥac (r) = rho₀* (1 - 2GM/rc²). This model predicts that decoherence rates are suppressed near massive objects — in direct opposition to the Diosi-Penrose model, which predicts enhancement near mass. The sign reversal produces a measurable fractional difference of 3GM/rc² between the two model predictions. We identify that quantum decoherence and macroscopic void decay are the same physical process at different scales, both governed by local vacuum bubble density eroding void-pair boundaries. We propose an experimental protocol using atomic interferometry at varying gravitational potentials, achievable with existing space-based platforms, that discriminates between this model and Diosi-Penrose by sign alone. For trapped ion qubits with coherence times of order 100 seconds, the predicted fractional improvement between Earth surface and the International Space Station is 8. 22 x 10^-11.
Luke Alexander Martin (Fri,) studied this question.