Quantum mechanics is among the most successful physical theories, yet its formulation and empirical testing rely on classical structures. Following Lev Landau and Niels Bohr, this reliance is not merely pragmatic: quantum observables acquire empirical meaning only relative to classical reference frames, and, in practice, quantization starts from classical models. At the same time, the two domains display forms of mutual irreducibility: intrinsically quantum features (that is, spin and exchange statistics) have no counterpart in the phase-space ontology of classical point-particle mechanics, while classical trajectory chaos does not arise straightforwardly from unitary quantum evolution in closed systems. A hierarchy is commonly established between classical and quantum theories, namely, a claim of ontological and explanatory priority according to which quantum mechanics is fundamental and classical mechanics is only a limiting case. This claim is less secure than is often assumed; therefore, the traditional hierarchy deserves to be examined. In this paper, we argue that a quantum–classical framework provides an effective and structurally faithful representation of empirically accessible physical systems in regimes where quantum and classical degrees of freedom coexist within a single, consistent effective dynamical description. To give this point of view a firm theoretical basis, we discuss the quasi-Lie formal structure underlying quantum–classical hybrid dynamics, with applications ranging from gravity and condensed matter to open, driven systems in biology and complex media.
Quantum mechanics is among the most successful physical theories, yet its formulation and empirical testing rely on classical structures. Following Lev Landau and Niels Bohr, this reliance is not merely pragmatic: quantum observables acquire empirical meaning only relative to classical reference frames, and, in practice, quantization starts from classical models. At the same time, the two domains display forms of mutual irreducibility: intrinsically quantum features (that is, spin and exchange statistics) have no counterpart in the phase-space ontology of classical point-particle mechanics, while classical trajectory chaos does not arise straightforwardly from unitary quantum evolution in closed systems. A hierarchy is commonly established between classical and quantum theories, namely, a claim of ontological and explanatory priority according to which quantum mechanics is fundamental and classical mechanics is only a limiting case. This claim is less secure than is often assumed; therefore, the traditional hierarchy deserves to be examined. In this paper, we argue that a quantum–classical framework provides an effective and structurally faithful representation of empirically accessible physical systems in regimes where quantum and classical degrees of freedom coexist within a single, consistent effective dynamical description. To give this point of view a firm theoretical basis, we discuss the quasi-Lie formal structure underlying quantum–classical hybrid dynamics, with applications ranging from gravity and condensed matter to open, driven systems in biology and complex media.
It is shown that a coherent understanding of all quantized phenomena, including those governed by unitary evolution equations as well as those related to irreversible quantum measurements, can be achieved in a scenario of successive nonequilibrium phase transitions, with the lowest hierarchy of these phase transitions occurring in a ``resonant cavity'' formed by the entire matter and energy content of the universe. In this formalism, the physical laws themselves are resonantly-selected and ordered in the universe cavity in a hierarchical manner, and the values of fundamental constants are determined through a Generalized Mach's Principle. The existence of a preferred reference frame in this scenario is shown to be consistent with the relational nature of the origin of physical laws. Covariant unitary evolution is shown to connect smoothly with the reduction of wavefunction in the preferred frame during quantum measurement. The superluminal nature of quantum processes in the lowest hierarchy coexists with the universal speed limit obeyed by processes in higher hierarchies. A natural quantum-to-classical transition is also obtained which is stable against the diffusive tendency of the unitary quantum evolution processes. In this formalism a realistic quasi-classical ontology is established for the foundations of quantum mechanics.
This document presents the Universal Correlational Lattice (UCL) as a general theoretical framework for constructing physical models directly from correlational structures, without assuming spacetime, fields, or quantum states as fundamental entities. The UCL formalism is built around a universal correlational kernel defined over relational sites, from which effective notions of dynamics, observables, uncertainty, and emergent geometry arise through explicit variational and coarse-graining procedures. Rather than postulating equations of motion or quantization rules a priori, the framework provides a model-building methodology: physical laws appear as effective descriptions of stable correlational configurations. This document is not a phenomenological fit nor a proposal of a specific new particle or interaction. Instead, it serves as a theoretical construction manual, showing how to: Define correlational degrees of freedom and their internal parameters, Construct effective observables from correlational averages, Derive emergent dynamics through functional variation, Identify classical, quantum-like, and geometric regimes as limits of the same underlying structure, Build toy models and progressively refine them toward empirical applicability. Uncertainty, probabilistic behavior, and apparent quantum effects are treated as emergent properties of incomplete access to correlational information, not as fundamental axioms. Likewise, time is introduced through internal correlational evolution and synchronization, rather than assumed as an external background parameter. The goal of the UCL framework is to provide a unified, internally consistent base from which models relevant to particle physics, gravity, and cosmology can be constructed and compared with existing theories such as Quantum Field Theory and General Relativity, while remaining agnostic about their ultimate empirical success. This work is intended for researchers interested in: Foundations of physics, Emergent spacetime and dynamics, Alternative formulations of quantum theory, Correlational and relational approaches to physical law. Empirical validation is not claimed at this stage; instead, the emphasis is placed on conceptual completeness, internal consistency, and explicit model-building capability.
Classical mechanics and quantum mechanics are two of the most successful scientific theories ever discovered, and yet how they can describe the same world is far from clear: one theory is deterministic, the other indeterministic; one theory describes a world in which chaos is pervasive, the other a world in which chaos is absent. Focusing on the exciting field of 'quantum chaos', this book reveals that there is a subtle and complex relation between classical and quantum mechanics. It challenges the received view that classical and quantum mechanics are incommensurable, and revives another, largely forgotten tradition due to Niels Bohr and Paul Dirac. By artfully weaving together considerations from the history of science, philosophy of science, and contemporary physics, this book offers a new way of thinking about intertheory relations and scientific explanation. It will be of particular interest to historians and philosophers of science, philosophically-inclined physicists, and interested non-specialists.
Classical mechanics and quantum mechanics are two of the most successful scientific theories ever discovered, and yet how they can describe the same world is far from clear: one theory is deterministic, the other indeterministic; one theory describes a world in which chaos is pervasive, the other a world in which chaos is absent. Focusing on the exciting field of 'quantum chaos', this book reveals that there is a subtle and complex relation between classical and quantum mechanics. It challenges the received view that classical and quantum mechanics are incommensurable, and revives another, largely forgotten tradition due to Niels Bohr and Paul Dirac. By artfully weaving together considerations from the history of science, philosophy of science, and contemporary physics, this book offers a new way of thinking about intertheory relations and scientific explanation. It will be of particular interest to historians and philosophers of science, philosophically-inclined physicists, and interested non-specialists.
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.
Across machine learning, physics, quantum theory, and the biological sciences, many systems exhibit the same fundamental transition: a probabilistic representation of possible states gives rise to a single, externally accessible outcome. Although these processes differ in substrate, scale, and mechanism, they share a minimal structural form involving a description of alternative possibilities, constraints that determine when one becomes admissible, and the resulting realized state. This article develops a substrate-independent framework that formalizes this shared structure. We define a realization condition as the minimal set of constraints under which a probabilistic state description yields a definite, externally accessible outcome, and argue that the role traditionally attributed to an “observer” in quantum theory can be understood in these functional terms. We examine four distinct domains — large language models, information-based physical theories, quantum measurement, and biological decision making — and show that each instantiates this transition in a structurally homologous way without implying mechanistic or ontological equivalence. The framework clarifies the functional role of observation in quantum theory, provides a common vocabulary for cross-domain comparison, and identifies structural expectations that may guide empirical work on uncertainty resolution and outcome formation. The framework is deliberately limited to describing the form of this transition rather than its underlying mechanisms, but it offers a basis for interdisciplinary analysis and a foundation for further theoretical development.