This paper develops an operational framework for analyzing persistence and branching of observer states using concepts from quantum information theory and quantum error correction. Observer states are modeled as encoded informational structures within code subspaces, and persistence is defined in terms of constrained recoverability under a specified class of allowed operations. The framework introduces persistence neighborhoods and recoverability-based continuity measures using fidelity and information geometry. Branching processes are analyzed operationally through reduced-state structure and local recoverability rather than metaphysical identity claims. Connections to decoherence, Everettian branching, and quantum information constraints such as no-cloning and no-deleting are discussed. The paper does not propose a theory of consciousness or derive metaphysical identity conditions from physics. Instead, it provides a formal structure for studying operational persistence under branching dynamics within a quantum-information-theoretic setting.
This paper develops an operational framework for analyzing persistence and branching of observer states using concepts from quantum information theory and quantum error correction. Observer states are modeled as encoded informational structures within code subspaces, and persistence is defined in terms of constrained recoverability under a specified class of allowed operations. The framework introduces persistence neighborhoods and recoverability-based continuity measures using fidelity and information geometry. Branching processes are analyzed operationally through reduced-state structure and local recoverability rather than metaphysical identity claims. Connections to decoherence, Everettian branching, and quantum information constraints such as no-cloning and no-deleting are discussed. The paper does not propose a theory of consciousness or derive metaphysical identity conditions from physics. Instead, it provides a formal structure for studying operational persistence under branching dynamics within a quantum-information-theoretic setting.
This paper proposes a recoverability-based framework for understanding quantum measurement, addressing the long-standing measurement problem from an information-theoretic perspective. Rather than assuming a fundamental wavefunction collapse, the framework describes observation as a transition in the recoverability of phase information encoded in system–environment correlations. As interactions with the environment disperse this information, the ability to reconstruct coherent quantum states becomes effectively lost, resulting in the emergence of classical behavior. A key feature of this approach is its interpretation independence. The same formal structure accommodates both collapse and non-collapse interpretations, allowing a clear separation between observable phenomena and interpretative assumptions. In this sense, the work reframes the measurement problem not as a question of physical collapse, but as a problem of information accessibility and recoverability. The framework is connected to experimentally relevant concepts such as decoherence, interference loss, and quantum error correction, providing a unified structural perspective across quantum foundations and quantum information. This work does not introduce a new dynamical law, but instead offers a conceptual reorganization of the measurement problem, potentially serving as a bridge between existing interpretations. quantum measurementmeasurement problemdecoherencequantum informationrecoverabilitywavefunction collapsequantum foundations
(This version has been superceeded, see v.3) Contemporary approaches to physical unification typically emphasize dynamical laws, interpretive frameworks, or information-theoretic reconstructions. Less attention is given to the structural constraints that determine which physical descriptions can remain coherent and stable under interaction, scale transition, and aggregation. This paper develops a constraint-first analysis of coherence, arguing that persistence and unification require restrictions on admissible physical continuations that are not reducible to dynamics alone. Within the framework referred to here as Quantum Coherence Theory (QCT), coherence is treated not as a fragile quantum resource but as a structural property governed by interaction geometry and constraint density. On this view, classical behavior emerges when accumulated constraints sufficiently narrow admissible evolution, while quantum behavior re-emerges when constraints are relaxed. The account does not introduce new dynamics, collapse mechanisms, or modifications of quantum formalism, but instead clarifies the conditions under which existing formalisms yield stable, unified descriptions. The resulting constraints distinguish QCT from observer-centric, intrinsic-collapse, and purely descriptive decoherence accounts, while remaining compatible with globally unitary dynamics. Formal analysis in later sections develops operational redundancy conditions, admissibility constraints on joint states, and rigidity-style arguments linking redundant record structure to the stability of classical descriptions. These results do not constitute a complete theory of unification, but they narrow the space of physically admissible descriptions and clarify the structural role of coherence in bridging quantum and classical regimes.
The quantum measurement problem persists because physics has never provided an operational definition of "observer" specifying which physical interactions constitute observations. We apply a thermodynamic operational definition developed from a prior observer framework: an observer is any self-maintaining bounded system that reduces entropy through differential environmental processing, where the system's persistence depends on the character of that processing. We distinguish between measurement (any interaction satisfying the definition's first two conditions, producing decoherence that suppresses quantum interference) and observation (an interaction involving a system satisfying all three conditions, producing autonomous, feedback-sustained decoherence). This distinction resolves the observer ambiguity in the canonical measurement-problem thought experiments: it specifies which systems observe, where in any causal chain observation occurs, and why the intuitive placement of the Heisenberg cut at the apparatus is practically correct. The Frauchiger-Renner inconsistency becomes identifiable and addressable once observer status is operationally assigned, because the definition identifies where the domain of unrestricted unitary description must be constrained. The nature of that constraint (collapse, irreversible branching, transaction completion) is interpretation-dependent; the criterion for where it applies is not, though the strength of the resulting resolution varies across interpretations. The definition does not resolve the problem of definite outcomes, derive the Born rule, or select the preferred basis. It resolves the component of the measurement problem that has blocked progress on those questions: the absence of any criterion for which systems perform observations.
Abstract Under unitary quantum mechanics, decoherence redistributes information into systemenvironment correlations but does not destroy it. The statement that information remains "in the environment" is operationally incomplete: it may be globally present without being locally readable or actively recoverable under realistic constraints. We distinguish three notions-presence, readability, and recoverability-and show that they are operationally distinct. In controlled simulations of four decoherence models (random circuits, Trotterized Ising, isotropic Heisenberg, CNOT fan-out), we find that recovery is inverse-specific: the correct inverse of the decoherence process succeeds while generic circuits of com parable depth fail. Coupling geometry further shapes accessibility: anisotropic Ising and isotropic Heisenberg dynamics exhibit sharply different local capture structure despite comparable scalar decoherence indicators. On superconducting (Rigetti Ankaa-3) and trapped-ion (IonQ Forte) hardware, exact inverse recovery remains observable on both platforms. On IonQ, the geometry-depen dent capture separation between Ising and Heisenberg dynamics reappears (∼ 10 × in capture efficiency), while on Rigetti it is suppressed to the noise floor by routing overhead—indicating that local accessibility is more hardware-sensitive than global recoverability. The central empirical result is not that exact inversion can restore decohered correla tions—a consequence expected under unitary control—but that decoherence models with comparable scalar indicators and identical global recoverability can produce sharply different local accessibility structures, and that this difference is selectively visible depending on hardware compilation overhead. These results do not establish asymptotic hardness barriers or distinguish between interpretations of quantum mechanics. They support a narrower conclusion: the operational accessibility of decohered information is determined by coupling geometry, not merely by the degree of decoherence, and whether it remains readable or recoverable depends jointly on interaction structure, observer access, and available control operations.
This work presents a constraint-based meta-framework for understanding persistent foundational dualities across physics, biology, and consciousness studies. Rather than proposing new physical mechanisms or historical cosmologies, it formalizes a post-reductionist perspective in which no globally sufficient singular description of reality is admissible. The framework replaces substance with persistence as the primary ontological primitive and treats irreducible dualities (e.g., wave–particle, observer–observed, gene–environment) as structural necessities rather than epistemic gaps. Scientific progress is reframed as translation between complementary descriptions instead of unification by collapse. Consciousness is formally introduced as a coherence-seeking interface process that operates across irreducible dualities, explaining its persistent tension with fragmentation and meaning without invoking metaphysical claims, panpsychism, or interventionist implications. From the axioms follow explicit structural limits, including the impossibility of a final theory, a total observer, permanent non-dual consciousness, or total control of complex systems. The framework is compatible with existing physical and biological theories and is intended as a stabilizing methodological guide for post-reductionist science. Ethical containment is built in by design: no inference from this work licenses the manipulation, collapse, or redesign of foundational dualities.
This paper is the seventh in a sequence developing an interpretive framework that redescribes physical reality as a causally consistent history of information updates rather than as a collection of objects independently existing within spacetime. Two prior results set up its question. The third paper (Uchida, 2026c) characterized public finality—recoverability of a committed fact by many mutually independent accessors, non-disturbingly and repeatably—as a broadcast redundancy: an effectively classical pointer value proliferated across many disjoint environmental fragments, approximately in the form of spectrum broadcast structure. The fourth paper (Uchida, 2026d) read the evaporating black hole as the regime in which a committed interior record crosses, at the Page time, from hidden to recoverable encoding, reconstructible from the radiation through entanglement-wedge reconstruction; and the parent framework (Uchida, 2026a, §10) had flagged holographic quantum error correction as a place its language of protected, redundantly encoded, locally recoverable records might find content. The present paper makes that content precise as a structure theory of recoverable records, kept separate from any claim of new physics or any suggestion that the framework derives the underlying results. The central claim is conditional and structural. The framework does not claim that every recoverable piece of information is a code, that the universe is literally a quantum error-correcting code, or that AdS/CFT describes our universe. It claims that when information qualifies as an erasure-recoverable record because an encoding preserves a logical degree of freedom—or a logical operator algebra—against a specified family of physical erasures, then that recoverability is formalized as an exact or approximate quantum error-correcting structure, in which each correctable erasure leaves an authorized complementary region supporting a recovery map. That formalization is itself an established mathematical classification; the paper's interpretive contribution is to read the series' recoverable record through it, and to set it against a second, distinct architecture. Broadcast redundancy makes the same effectively classical value legible from many disjoint fragments; erasure-correcting redundancy protects noncommuting logical quantum information by keeping each correctable erased region ignorant of—approximately private with respect to—the protected logical content, while suitable remaining regions recover it. The formal engine of this distinction is the duality between correctability and privacy (the information–disturbance tradeoff), not the no-cloning theorem; no-cloning, with the access structure of quantum secret sharing, survives as the reason independently usable recovery regions for arbitrary unknown logical quantum information must overlap. Three commitments keep the reading honest. First, it separates three senses of "record"—protected logical quantum information, a committed classical record, and a publicly final record—and insists that recovery or decoding restores access to logical quantum information but does not, by itself, commit a classical value; commitment additionally requires measurement, pointer imprinting, decoherence, and stabilization (Uchida, 2026f), and public finality a still later broadcast. Second, holographic quantum error correction is offered as the sharpest worked model of the distinction, with exactly solvable tensor-network toy codes (exact within the model) kept distinct from realistic semiclassical holographic reconstruction beyond those limits (generally treated as approximate), and both from the further question of state-dependence. Third, code-recoverability does not by itself imply public finality: protected quantum information can be recoverable from authorized regions while remaining non-public. The framework relabels code structure as the architecture of recoverability and derives none of it, making no independent empirical prediction. Its disciplined thesis is that codes protect recovery; broadcasts create publicity—different architectures that a single physical history may nonetheless realize in sequence.