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From Degree-of-Freedom Manipulation to Irreversibility

Haiqing Wan

Published Aug 7, 2026• 0 citations
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Abstract

Abstract The transition from microscopic reversible dynamics to macroscopic irreversible thermodynamics in statistical mechanics, the transformation from pure states to mixed states during quantum decoherence, and the transition from quantum superposition states to classical definite states in quantum measurement have long been regarded as three independent fundamental physical puzzles. This paper demonstrates that the three processes share a unified mathematical root: the filtering, truncation or projection of system degrees of freedom renders the information carried by partial degrees of freedom unreconstructable within the reduced description framework, and irreversibility spontaneously emerges in the remaining description space. Based on the rigorous derivation of Hilbert’s sixth problem proposed by Deng et al., Zurek’s environment-induced decoherence theory, and the three-stage model of temporal relativity proposed by the author, this paper extracts the mathematical structure of the three types of physical processes and constructs an axiomatic unified framework. This paper further clarifies that various filtering operations are essentially equivalent to the selection of reference frames by the observation system; any descriptive subject with finite information bandwidth must select a reference benchmark, and the arrow of time is an emergent characteristic of this selection behavior under reduced description. This paper distinguishes between global information conservation and local unreconstructable information, emphasizing that the theoretical framework does not violate unitary quantum evolution, and proposes quantitative predictions verifiable by attosecond physics and superconducting quantum experiments.

DOI
10.5281/zenodo.21830649

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Abstract Fundamental discrepancies exist among the foundational postulates of classical mechanics, relativity and quantum mechanics, leaving long-standing open physical puzzles including the origin of the arrow of time, quantum measurement collapse and the nature of spacetime. This paper proposes a self-consistent unified physical paradigm: the physical essence of a reference frame is the selective filtering of the full degrees of freedom of a system. All classical, relativistic and quantum physical theories constitute effective reduced descriptions of degrees of freedom under specific rules imposed by reference frames. Core phenomena such as temporal irreversibility, wave-function collapse, the constancy of the speed of light and the quantum-classical transition are not fundamental ontological properties of the universe, but emergent effects arising from filtering mappings introduced by finite-bandwidth observers. This work establishes an axiomatic framework for reference frames and degree-of-freedom filtering, defining projection filtering mappings, the principle of vanishing relative degrees of freedom, and the dimensionless filtering ratio. Within this framework, we reconstruct classical mechanics, special and general relativity, quantum decoherence and quantum measurement theory. Three categories of irreversible mechanisms — statistical coarse-graining, environmental partial-trace decoherence and time-domain sampling truncation — are integrated into a single mathematical structure. A universal dimensionless filtering ratio is defined. We clarify that the continuity of the control parameter does not imply that observables must evolve smoothly. Conceptually, the system can exhibit three regimes: quantum superposition, intermediate transition and classical state. Experiments on quantum bits at the Weizmann Institute provide preliminary observational hints, yet further verification is required; no specific form of the response curve is assumed in this paper. Three falsifiable quantitative predictions are put forward, involving attosecond spectroscopy, decoherence of superconducting qubits and cold-atom interferometry. We compare the present paradigm with relational quantum mechanics, QBism and consistent histories, discuss the ontological implications of time, observers and irreversibility, and outline extensions towards quantum gravity and cognitive science.
We present a unified operational framework for the arrow of time grounded in irreversible information loss. While microscopic physical laws are time-reversal invariant, macroscopic irreversibility arises when systems overwrite metastable records. We show that recent reversible quantum-control experiments do not reverse time, but instead operate in regimes where no logically irreversible record is created. To formalize this, we introduce the **forgetting rate** (Ξcr)(\Xi_{\mathrm{cr}})(Ξcr​), a coarse-grained rate defined on physically selected metastable record states (e.g., pointer states, memory registers, or macroscopic configurations). Unlike standard entropy production, which is expressed in terms of microscopic transition asymmetry, (Ξcr)(\Xi_{\mathrm{cr}})(Ξcr​) captures the **rate of irreversible record overwriting**. In this formulation, entropy production obeys the lower boundS˙irr≥kB Ξcr,\dot{S}_{\mathrm{irr}} \ge k_B \,\Xi_{\mathrm{cr}},S˙irr​≥kB​Ξcr​,consistent with Landauer's principle but expressed at the level of record dynamics. Within this framework, thermodynamic, quantum-measurement, psychological, and cosmological arrows emerge as substrate-dependent manifestations of Ξcr>0\Xi_{\mathrm{cr}} > 0Ξcr​>0. Temporal asymmetry is therefore not a single global property, but a distributed feature of physical information-processing systems. The approach naturally explains the decoupling of arrows in composite systems and identifies experimentally accessible regimes where irreversibility can be locally suppressed. This work does not introduce a new microscopic law but provides a unifying, operational reformulation that connects information thermodynamics, decoherence theory, and memory dynamics through a single coarse-grained rate.
Abstract This article presents a revised and conceptually refined formulation of a previously proposed Temporal Interpretation of quantum measurement, explicitly addressing the physical nature of wavefunction collapse. While the original proposal emphasised relativistic aspects of momentum superpositions, the present work clarifies the interpretation within the standard formalism of quantum mechanics, without introducing new dynamics or experimental predictions. Unitary evolution is read as a process of differentiated phase accumulation between branches of a quantum state. In relativistic contexts, phase differentials can be structurally related to effective proper-time differentials, allowing the introduction of a notion of temporal compatibility that provides a physically grounded account of decoherence. When such differentials exceed a characteristic scale, interference between branches becomes operationally inaccessible, while global unitarity is preserved. The observer is treated as a physical system endowed with an irreversible proper time associated with macroscopic, entropic dynamics. Within this framework, collapse is explained as an emergent physical phenomenon arising from the irreversibility of the observer’s proper time, which prevents the reconstruction of phase coherence after an interaction. Collapse is therefore neither a fundamental dynamical mechanism nor an objective event in space-time, but a necessary consequence of temporal irreversibility in physical observers. This formulation sharpens the distinction between decoherence and collapse, preserves full consistency with the Born rule, and positions the Temporal Interpretation as a competing interpretative framework that provides a concrete physical explanation for the quantum–classical transition, improving and clarifying the original proposal. This version clarifies the operational status of the interaction time, refines Sections 5.3 and 5.4, and standardises references and editorial structure. No changes to the formalism or conclusions.
Abstract The century-long Bohr–Einstein debate over the foundations of quantum mechanics appears to be an ontological dispute concerning whether physical reality exists objectively. In essence, however, it stems from the two sides implicitly adopting different hierarchical reference frames without explicit clarification. Based on the degree-of-freedom filtering framework, this paper proposes a hierarchical reference frame model. At the birth of quantum mechanics lies a fundamental reference-frame amnesia: the theory first defines eigenstates within the abstract Hilbert space, which mathematically refer to global possibilities without introducing any reference frame (Level 0). Nevertheless, concrete calculations rely on space-time reference frames to construct wave functions, and the superposition exhibited by the latter is then termed “quantum superposition”. The transition from toconstitutes a genuine, irreversible introduction of a reference frame, realizing a filtering mapping from to . Insufficient sampling rates in early experimental instruments statistically lent superficial support to this amnesia. Recent high-precision experiments gradually reveal that the so-called “superposition state” is largely an apparent phenomenon arising from limited measurement bandwidth. Within this model, Bohr’s “indeterminate state” requires dual judgment: his intention points to Level 0, yet his practical standpoint resides at Level 1. Einstein’s “determinate state” corresponds to physical states presupposing space-time as the reference frame. The century-long arguments surrounding the EPR paradox and Bell inequalities are essentially deepened manifestations of this hierarchical confusion. This paper further demonstrates that the framework offers a unified account of the measurement problem, wave–particle duality, the Fourier limit relation and quantum Zeno effect, delayed-choice experiments, quantum entanglement, quantum tunneling, and other phenomena. Without introducing extra dimensions or parallel worlds, the framework merely elevates “reference frame” from a background assumption to a core variable, providing a self-consistent, intuitive and unified epistemological foundation for the foundations of quantum mechanics.
The goal of this thesis is to define the concept of coarse-graining in quantum systems through measurements and to develop a unified mathematical framework for macroscopic states, operations, correlations, and entropy.Within this framework, irreversible phenomena arise from the loss of statistical information that is accessible to macroscopic observers.To achieve this goal, we rigorously define macroscopicity.This thesis investigates observational entropy, a concept that unifies Boltzmann entropy, Gibbs entropy, von Neumann's macroscopic entropy, and diagonal entropy.Our approach to explaining how irreversibility arises in isolated quantum systems is based on this unified perspective.When the initial state is "macroscopic," we use Petz's theory of statistical sufficiency to show that observational entropy strictly increases with unitary time evolution.Furthermore, we show that, for any initial state, the probability of the system's observational entropy increasing and rapidly reaching its maximum value under random unitary time evolution is extremely high.Specifically, we demonstrate that when measurements on a quantum system are sufficiently coarse-grained relative to its size, its initial state (whether pure or mixed) becomes indistinguishable from the maximally mixed state through random time evolution.We show that this holds not only for random time evolutions sampled according to the Haar measure, but also for approximate 2-designs, which are considered more physically realistic models.Next, we extend this framework by introducing positive operator-valued measures (POVMs) and quantum prior states.This allows us to construct a unified inferential framework for macroscopic states.A macroscopic state can be characterized using equivalent algebraic and constructive formulations based on quantum statistical sufficiency.This approach is based on the concept of an observational deficit, which quantifies the degree to which a state is "irretrodictable" relative to prior and measurement.This structure is formulated as an "inferential reference frame" that encapsulates the observer's informational perspective.Furthermore, we treat macroscopic states as free states and construct the resource theory of microscopicity.This theory unifies existing theories of coherence, athermality and asymmetry.Finally, we extend this framework to the study of quantum correlations under observational constraints.This enables us to show that quantum correlations, such as entanglement and quantum discord, are context-dependent resources that depend on the observer's reference frame.I would like to express my deepest gratitude to my supervisor,
Abstract: The quantum measurement problem has been the deepest conceptual difficulty since the birth of quantum mechanics. Standard quantum mechanics accepts wavefunction collapse as an independent postulate but never provides a physical explanation. The decoherence approach attributes collapse to the interaction between the system and its environment, but faces two fundamental limitations: the “infinite regress” problem and the “insufficiency of decoherence” problem. Within the framework of the Self-Construction Theory (SCT), this paper provides a complete resolution of the measurement problem. The core thesis is that quantum measurement is not a fundamental process independent of the laws of physical evolution, but rather a local manifestation of constructive renormalization—the scale evolution of the spacetime complex field KKK from microscopic degrees of freedom to macroscopic effective descriptions. The origins of wavefunction collapse, decoherence, and the Born rule receive a unified first‑principles interpretation in this framework. SCT’s spontaneous decoherence mechanism is the key to the resolution. Constructive renormalization inherently involves information loss—the integrated‑out microscopic degrees of freedom no longer exist in the macroscopic effective description. During a measurement, the measuring apparatus possesses a huge number (∼1023\sim10^{23}∼1023) of microscopic degrees of freedom. When the apparatus interacts with the measured system, constructive renormalization triggers information compression of these degrees of freedom—the apparatus can no longer distinguish which branch of the superposition it is in, and quantum coherence is thus spontaneously lost. No “external environment” is needed—the constructive renormalization dynamics of spacetime itself is the ultimate source of decoherence, thereby completely solving the “infinite regress” problem. Among the probability distribution given by the Born rule, the weights of non‑maximal probability branches are further suppressed by information compression under the huge number of microscopic degrees of freedom, so that macroscopic observers can perceive only a definite outcome in the effective description. The information loss caused by constructive renormalization is ontological—it does not rely on any approximation or truncation, thus fundamentally solving the “insufficiency of decoherence” problem. The Born rule—that measurement outcomes occur with probabilities given by the squared amplitudes—is directly derived from the constructive integral structure in SCT. In the constructive renormalization limit, interference terms between different configurations are naturally suppressed by off‑diagonal phase randomization, and the system automatically switches to a classical probabilistic description. In the diagonal density matrix representation, the squared amplitude is the only natural weight that is simultaneously real and non‑negative. Hence the Born rule is not an additional postulate of quantum mechanics but a necessary and unique manifestation of the relative frequencies of the constructive integral in the constructive renormalization limit. This derivation is rigorous within the mathematical framework of constructive renormalization—it does not rely on any approximations or truncations. SCT’s quantum measurement theory is deeply unified with the black hole information paradox. The “collapse” in quantum measurement and the “information loss” in black hole evaporation are different manifestations of the same core mechanism—the redistribution of information due to constructive renormalization—in two extreme physical situations. In quantum measurement, information is redistributed into the degrees of freedom of the macroscopic apparatus; in black hole evaporation, information is redistributed into the time‑point configurations on the horizon. This unification is the strongest proof of the universality of constructive renormalization as an information‑processing mechanism. Keywords: quantum measurement; spontaneous decoherence; constructive renormalization; Born rule; wavefunction collapse; information redistribution; Self-Construction Theory