Autonomous Quantum Measurement Chains with Faithful Equilibrium Records

A measurement apparatus must do more than produce the correct final outcome frequencies: its records must faithfully preserve its own earlier declarations. This paper constructs autonomous quantum measurement chains that address both requirements within a specified nonrelativistic Schrödinger–Bohmian model. Assuming Bohmian guidance, complete initial quantum equilibrium, and a finite apparatus stock prepared independently of the unknown input, the manuscript gives a Hamiltonian bounded below that implements each fixed finite measurement programme to any prescribed positive tolerance. The complete model retains the source, pointers, internal clock, coherent resource products, copied archives, reset receivers, and an inaccessible quantum reference. Forced harmonic traps supply exact pointer motion. Retained orthogonal keys permit stationary record storage, while explicit copying and transfer preserve earlier records before working registers are reset. A finite-mass quantum clock replaces external time-dependent control. Weighted derivative estimates quantify its approximation error and bound the absolute probability current through archive decision surfaces. The resulting theorem separates final quantum-output accuracy from historical-record fidelity, including preservation throughout designated holding intervals. It retains coherent null outcomes and provides reproducible finite examples. Every positive tolerance uses finite resource choices for the fixed programme and observation horizon, although Gaussian packets retain unbounded tails. This is a conditional implementation and error-control result. It does not derive the initial Born law, uniquely determine Bohmian guidance, establish closeness of complete microscopic trajectories, or demonstrate laboratory realization of the admitted interactions.