A Causal-Relational Closure Quantum Circuit Laboratory: From Interfering Connections to Future-Programmed Quantum Operations

Causal-relational closure (CRC) distinguishes fixed local records from relations that remain open to physically admissible future operations. A sequence of small quantum-circuit laboratories develops this distinction through interfering pairings, target-excluding routes, coherent measurement interactions, and future-programmed quantum gates. The central worked experiment records an informative pointer bit that predicts an input bit with probability 3/4. In one record branch, a later controller measurement distinguishes two prepared phases with conditional probabilities 5/6 and 1/6; in another, the same readout is completely uninformative. More strongly, the phase alternatives in the latter branch produce identical surviving quantum states and therefore cannot be distinguished by any subsequent measurement on the retained apparatus. A no-interaction control shows that phase distinguishability was lost rather than merely revealed by adding another detector. Explicit response matrices illustrate contract refinement, while a second quotient calculation identifies redundant pointer histories under a declared downstream-consumer contract and shows how archive access restores their distinction. State and channel identities, success probabilities, complete instruments, conventional precedents, and dephasing controls are supplied throughout. Established quantum operations provide the implementation language, while CRC supplies the constructive organising principle: fixed events and future-distinguishable relations are treated as different physical questions. The resulting connected circuit family makes that ontological distinction calculable, testable, and accessible without changing standard quantum probabilities.