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Phase Accumulation and Environmental Distinguishability in Quantum-to-Classical Transition Systems

David Wert

Published May 13, 2026• 0 citations
Publisher

Abstract

The quantum-to-classical transition is commonly described through decoherenceand environmental entanglement, yet quantitative measures of structured phaseorganisation within coherent quantum states remain comparatively underdeveloped.This work introduces a phase-organisation functional that measures the structuredphase separation encoded in the off-diagonal coherence channels of a quantumdensity matrix. The functional characterises the progressive conversion ofcoherent phase structure into environmentally encoded branch distinguishabilityduring open-system evolution. A minimal two-state model illustrates the evolution of phase organisation underdecoherence. Environmental degrees of freedom are modelled as distributedphase-encoding channels whose cumulative phase dispersion suppresses coherenceexponentially. An effective informational persistence quantity, termedinformational mass (Imass), is introduced operationally as a measure ofaccumulated environmental branch distinguishability. The framework connects phase accumulation, decoherence, entropy growth, andclassical distinguishability within a unified informational description whileremaining fully compatible with standard open quantum systems theory. Potentialapplications to coherence monitoring and hybrid quantum-classical architecturesare discussed. This is a working paper deposited to establish a citable DOI record.The framework is exploratory; limitations and open questions arediscussed explicitly in the paper. Part of the Q2C Research Initiative theoretical series. This paper establishes the phase-organisation functional and single-threshold Imass criterion as the foundational framework for the programme. Paper 2 (dual-parameter threshold structure, spectral Imass, entropy plateau conditions, and Mpemba-like trajectory crossings) is available at https://doi.org/10.5281/zenodo.20531722. Paper 3 (σ-algebra filtration structure) is in preparation.

DOI
10.5281/zenodo.20167963

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The quantum-to-classical transition is commonly described through decoherenceand environmental entanglement, yet quantitative measures of structured phaseorganisation within coherent quantum states remain comparatively underdeveloped.This work introduces a phase-organisation functional that measures the structuredphase separation encoded in the off-diagonal coherence channels of a quantumdensity matrix. The functional characterises the progressive conversion ofcoherent phase structure into environmentally encoded branch distinguishabilityduring open-system evolution. A minimal two-state model illustrates the evolution of phase organisation underdecoherence. Environmental degrees of freedom are modelled as distributedphase-encoding channels whose cumulative phase dispersion suppresses coherenceexponentially. An effective informational persistence quantity, termedinformational mass (Imass), is introduced operationally as a measure ofaccumulated environmental branch distinguishability. The framework connects phase accumulation, decoherence, entropy growth, andclassical distinguishability within a unified informational description whileremaining fully compatible with standard open quantum systems theory. Potentialapplications to coherence monitoring and hybrid quantum-classical architecturesare discussed. This is a working paper deposited to establish a citable DOI record.The framework is exploratory; limitations and open questions arediscussed explicitly in the paper. Part of the Q2C Research Initiative theoretical series. This paper establishes the phase-organisation functional and single-threshold Imass criterion as the foundational framework for the programme. Paper 2 (dual-parameter threshold structure, spectral Imass, entropy plateau conditions, and Mpemba-like trajectory crossings) is available at https://doi.org/10.5281/zenodo.20531722. Paper 3 (σ-algebra filtration structure) is in preparation.
The single-threshold model of the quantum-to-classical transition treats classicality as a binary crossing of a single Imass criterion. This paper argues that the transition is better described by a dual-parameter structure: a lower threshold α at which coherence becomes operationally negligible, and an upper threshold β at which classical distinguishability becomes stable against perturbation. The interval [α,β] constitutes a hysteresis gate within which the transition is directionally asymmetric — re-coherence remains possible below β but is operationally suppressed beyond it. A spectral decomposition of informational mass (Imass) is introduced, resolving the total accumulated environmental distinguishability into mode-resolved contributions. This decomposition enables precise characterisation of entropy plateau conditions: regions of near-zero entropy growth arising when dominant spectral modes have saturated while subdominant modes continue accumulating slowly. As a derived consequence of the dual-threshold structure, the framework predicts Mpemba-like trajectory crossings between systems initialised at different Imass values. A system with higher initial Imass can exhibit lower entropy than a system with lower initial Imass at intermediate times, owing to earlier entry into the entropy plateau regime. This prediction is mechanistically distinct from existing quantum Mpemba results and constitutes a testable consequence of the framework. A minimal three-level qutrit Lindblad model is developed to illustrate the dynamics numerically.
Description : This work introduces a novel, model-independent diagnostic framework for quantifying quantum decoherence in primordial inflationary perturbations. The study addresses the fundamental problem of the quantum-to-classical transition in cosmology by defining a normalized persistence functional that captures the suppression of quantum coherence over time. Within an open quantum system approach, each perturbation mode is treated as an effective quantum degree of freedom interacting with an environment, leading to Gaussian suppression of off-diagonal density matrix elements. The proposed functional provides a direct and scalable measure of decoherence efficiency without relying on detailed microscopic modeling. A key feature of the framework is the introduction of a residual coherence parameter, which accounts for possible late-time deviations from complete classicalization. The work further establishes a monotonicity property for the decoherence functional and connects the persistence measure to entropy growth, offering an information-theoretic interpretation of the decoherence process. Importantly, the framework suggests a phenomenological link between residual coherence and observable non-Gaussianity in the cosmic microwave background, opening a pathway for potential observational constraints. The proposed diagnostic functional is broadly applicable across inflationary models and provides a unified tool for comparing decoherence efficiency under different environmental interactions. This work lays the foundation for future studies on quantum signatures in cosmological observables and the persistence of quantum features in the early universe. Keywords : Quantum Decoherence Inflationary Cosmology Primordial Perturbations Open Quantum Systems Quantum-to-Classical Transition Non-Gaussianity Cosmological Perturbation Theory Density Matrix Quantum Cosmology Early Universe Physics Decoherence Functional Entropy and Information Theory
This research introduces a novel quantitative framework for understanding one of the most fundamental questions in theoretical physics: How and when do quantum systems become classical? By developing a normalized Quantum Persistence Function (QPF) , we provide a continuous measure of residual quantum coherence in open systems interacting with their environment. The framework is rigorously derived from the spin-boson model—a paradigm for studying decoherence—and distinguishes between Markovian (memoryless) and non-Markovian environments based on spectral density structure (Keywords) Quantum decoherence Inflationary cosmology Open quantum systems Quantum–classical transition Primordial perturbations Cosmic Microwave Background Non-Gaussianity Spin-boson model Environmental entanglement Planck mission
This paper presents a formal framework framing quantum decoherence as an information-theoretic phase transition at the quantum-to-classical boundary. We demonstrate that environment-induced superselection (einselection) can be characterized as a true dynamical phase transition where the system-environment coupling strength acts as a thermodynamic control parameter, and the suppression of off-diagonal density matrix elements functions as an order parameter analogous to magnetization in the Ising model. Using quantum mutual information, von Neumann entropy, and entanglement entropy, we track the operational flow of information from a quantum system into environmental degrees of freedom, demonstrating how a singular classical reality emerges via the redundant copying of pointer states into environmental fragments—a process governed by Quantum Darwinism. We analyze a simulated spin-boson model and random unitary circuits with tunable dissipation, extracting clear signatures of criticality including power-law scaling and diverging correlation times at a critical threshold . Crucially, we connect this behavior to recent advancements (2023–2025) in mixed-state topological order, establishing that decoherence-induced transitions map onto anyon condensation transitions within an errorfield double formulation. Finally, we explore the foundational implications of this framework: it sharpens the measurement problem via informational symmetry breaking, reframes observation as a high-decoherence thermodynamic limit, and introduces a Gödelian perspective by demonstrating that determining the critical threshold for arbitrary many-body environments is formally undecidable due to the non-computability of the spectral gap in the thermodynamic limit.
Quantum decoherence is both the fundamental mechanism underlying the quantum-to-classical transition and a major challenge for the development of scalable nanoscale quantum technologies. This work introduces a Quantum Phase Space (QPS) framework that provides a unified geometric description of decoherence. The framework is based on a dual structure consisting of an overcomplete continuous frame of minimum-uncertainty states that defines the QPS geometry, and an orthonormal basis that satisfies the strict mathematical requirements for decoherence within the Spectrum Broadcast Structure (SBS) objectivity criterion for pointer states. Within this framework, the variance-covariance matrix of the QPS ground states serves as a universal indicator of decoherence regimes:it is time-independent for Markovian (memoryless) dynamics, and time-dependent for non-Markovian dynamics with memory and information backflow. To illustrate the formalism, the Hu-Paz-Zhang (HPZ) model is generalized to include simultaneous position and momentum couplings to the environment, leading to a generalized non-Markovian master equation characterized by a spectral-density matrix. The corresponding evolution equations for the first moments (⟨p(t)⟩,⟨x(t)⟩)\ (\left\langle p(t) \right\rangle,\left\langle x(t) \right\rangle) (⟨p(t)⟩,⟨x(t)⟩) and for the ground covariance matrix establish a direct connection between microscopic environmental properties, classical-like trajectories and the QPS geometry. The proposed framework provides a unified theoretical foundation for modeling decoherence in nanoscale systems involving simultaneous position and momentum interactions with the environment. The QPS framework may thus bridge fundamental theory and practical quantum engineering, offering a promising coherent pathway to understand, control, and exploit decoherence at the nanoscience frontier.
This work proposes an operational framework, denoted OFID-G, to investigate whether quantum coherence remains fully reconstructible from locally accessible information, even when global unitary evolution is preserved. The framework is formulated within the Ontological Framework of Imbricated Degrees (OFID), in which physical states may involve degrees of freedom that are not fully accessible within a given local observational regime. Within this perspective, OFID-G defines a possible structural limitation on the local accessibility of coherence, without introducing any modification to quantum dynamics. The central concept is regime-dependent reconstructibility: coherence is said to be reconstructible if a single recovery operation, fixed by calibration alone, can operationally recover it across a tomographically informative family of preparations, and non-reconstructible if a persistent limitation remains despite such procedures. This state-independent formulation anchors the criterion in the theory of approximate recoverability of quantum channels. Rather than predicting a specific mechanism, the framework defines a falsifiable structural criterion distinguishing reconstructible and non-reconstructible regimes, based on controlled variation of physically relevant parameters. The approach remains fully compatible with standard quantum mechanics and does not invoke collapse models or deviations from unitarity. Its empirical content lies in testing whether all observed decoherence effects can be fully accounted for by known environmental mechanisms. This provides a minimal and operational test of the completeness of standard decoherence modeling, shifting the focus from dynamical mechanisms to structural limitations of information accessibility. The framework is developed within the OFID research program (DOI: 10.5281/zenodo.18868538); its concrete experimental realization is developed in a companion operational paper (DOI: 10.5281/zenodo.19351945). Project page :https://alexsasfrance.github.io/OFID-framework/