Finite Record Boundaries in Wigner's Friend Scenarios: Observer-Relative Distinguishability and Quantum Record Availability in Finite Distinction Systems

Official website: distinctiontheory.orgPublic portal for the start guide, papers, claim status, failure registry, prior-art boundary, and citation resources. Canonical GitHub repository:https://github.com/yiningwu-research/Distinction-Theory FDS-Q1 develops the quantum-record-boundary paper in the Q-series of Finite Distinction Systems (FDS) / Distinction Theory. It studies Wigner’s Friend scenarios as finite record-boundary promotion problems. The central claim is that a friend-relative operational record cannot be promoted into Wigner’s accessible fact algebra unless a physical record channel supplies sufficient cross-boundary mutual information. Q1 does not solve the measurement problem, derive the Born rule, replace decoherence theory, modify unitary quantum mechanics, or claim that consciousness causes collapse. It is not a collapse theory. It is a finite-record boundary theory: observers are treated as finite distinction-registers, and measurements are treated as stable record formation under finite capacity. The central quantitative object is the boundary-mismatch entropy MF|W = H2(ZF | ZW), where ZF is the friend’s accessible record class and ZW is Wigner’s accessible record class. A friend-relative record is Wigner-promotable to tolerance ε only when H2(ZF | ZW) ≤ ε, equivalently, I2(ZF; ZW) ≥ H2(ZF) - ε. Q1 carefully separates Wigner’s ignorance from physical coherence. Wigner’s ideal global coherent assignment requires isolation and reversible-control assumptions. Wigner’s operational state is instead obtained by tracing out inaccessible degrees of freedom. The friend’s internal record is represented as a stable record class relative to the friend’s accessible algebra, not as a claim of fundamental collapse. The paper introduces a concrete finite-record interface. An observer implements an operational measurement family MO = {EOz}, which outputs a finite classical record ZO. A POVM outcome counts as an FDS record only when it is stabilized in the observer’s register over a retention window [t, t + τ] with error probability at most δ. Thus Q1 treats record extraction as classical-register stabilization under finite accessibility, not as a fundamental projection or collapse trigger. Information-theoretic quantities are measured in bits: H2, I2, and C. When a physical entropy is associated with a record distribution, the conversion is S = kB ln 2 · H2. Q1 uses this convention because FDS tracks finite distinguishability in binary record units. Von Neumann entropy is used when the relevant object is a quantum reduced state rather than a classical record variable. The paper formulates several core results: a boundary-promotion criterion, a Wigner-friend boundary-separation proposition, a finite-access lower bound on friend-record reconstruction using data processing and Fano-style inequalities, and an objective-convergence condition through environmental redundancy. In the binary case, the reconstruction error satisfies a lower-bound relation involving the inverse of the binary entropy function on the monotone branch 0 ≤ Pe ≤ 1/2. Q1 also defines an objective availability threshold using environmental fragments. For fragments E1, ..., EN, the minimal fragment number is mε = min { m : I2(ZF; E1:m) ≥ H2(ZF) - ε }. A record becomes objectively available to a class of finite observers only when redundancy, observer capacity, and record stability are all sufficient. This connects Q1 to decoherence and quantum Darwinism while preserving the distinction between decoherence, internal record formation, and external record availability. The paper’s response to Frauchiger-Renner-style arguments is not a refutation of the theorem. Instead, Q1 provides a boundary-audit rule: a statement recorded in the friend’s accessible algebra cannot be inserted into Wigner’s accessible algebra unless boundary promotion succeeds. In slogan form: AF-fact does not imply AW-fact unless the physical promotion channel supplies sufficient mutual information. Q1 introduces a promotion strength ηF→W = I2(ZF; ZW) / H2(ZF), which organizes boundary-alignment regimes: no promotion, partial leakage, Wigner-promotable record, and full boundary alignment. Partial leakage licenses inference, not promotion. For quantum technology, Q1 distinguishes coherence preservation from record availability. It introduces the diagnostic record availability horizon τRAH = inf { t : I2(Zinternal; Zexternal(t)) ≥ H2(Zinternal) - ε }. This is a diagnostic time for external record availability, not a new fundamental timescale. It is intended to complement device metrics such as T1, T2, gate fidelity, readout fidelity, internal record stability, cross-boundary mutual information, record-erasure history, and reset or garbage-collection cost. The release includes deterministic normal-form demonstrations. They illustrate the record-boundary causal map, boundary-promotion condition, decoherence versus record availability, a three-bit toy model, the promotion lattice, and the relation map connecting FDS Core, T1, O1, Q1, P3/P4/P7, and Q2. These figures are conceptual normal forms, not quantum dynamical simulations and not empirical fits. This release includes the paper PDF, LaTeX source, reproducibility code, generated figures, CSV outputs, and model summary outputs.