This paper proposes a self-consistent and rigorous framework for quantum cosmology—Scale-Invariant Hierarchical Quantum Cosmology (SIHQC). Its core dynamical mechanism isenvironment-induced decoherence driven by energy flow. When the energy flow is zero, theUniverse as a closed quantum system resides in a pure coherent superposition state, where allmoments, spatial positions, and quantum branches coexist completely. When the energy flowexceeds the critical threshold, the decoherence process projects the Universe onto anobservable classical effective spacetime, naturally emerging a single "present", a single spatialposition, and a definite classical history.This framework postulates that the Universe originated from a scale-invariant hierarchicalquantum initial state with a strictly self-similar hierarchical structure. This state is rigorouslydefined via the inductive limit of Hilbert spaces, which completely circumvents the divergenceproblem caused by infinite tensor products in traditional quantum cosmology. Based on thetheory of open quantum systems and the mechanism of environment-induced decoherence,this paper systematically addresses fundamental issues in quantum cosmology, including thestructure of the initial singularity, the origin of the arrow of time, and the quantum-to-classicaltransition, using energy flow as the sole driving variable. It also discusses its implications for thedynamics of cosmic expansion.A universal and constant global decoherence threshold of the Universe ε0 = 1/τP exists in theframework, uniquely determined by the Planck time. The current temperature of the CosmicMicrowave Background (CMB) is a natural manifestation of this threshold in the low-energyUniverse, rather than an artificially input parameter. This model is fully compatible withstandard quantum mechanics, open system dynamics, thermodynamics, the classical limit ofgeneral relativity, and the ΛCDM cosmological model. It only introduces two free parametersconstrained by observations (the branch number and the hierarchy activation exponent ),and provides four physical inferences with clear falsifiability
This paper proposes a self-consistent and rigorous framework for quantum cosmology—Scale-Invariant Hierarchical Quantum Cosmology (SIHQC). Its core dynamical mechanism isenvironment-induced decoherence driven by energy flow. When the energy flow is zero, theUniverse as a closed quantum system resides in a pure coherent superposition state, where allmoments, spatial positions, and quantum branches coexist completely. When the energy flowexceeds the critical threshold, the decoherence process projects the Universe onto anobservable classical effective spacetime, naturally emerging a single "present", a single spatialposition, and a definite classical history.This framework postulates that the Universe originated from a scale-invariant hierarchicalquantum initial state with a strictly self-similar hierarchical structure. This state is rigorouslydefined via the inductive limit of Hilbert spaces, which completely circumvents the divergenceproblem caused by infinite tensor products in traditional quantum cosmology. Based on thetheory of open quantum systems and the mechanism of environment-induced decoherence,this paper systematically addresses fundamental issues in quantum cosmology, including thestructure of the initial singularity, the origin of the arrow of time, and the quantum-to-classicaltransition, using energy flow as the sole driving variable. It also discusses its implications for thedynamics of cosmic expansion.A universal and constant global decoherence threshold of the Universe ε0 = 1/τP exists in theframework, uniquely determined by the Planck time. The current temperature of the CosmicMicrowave Background (CMB) is a natural manifestation of this threshold in the low-energyUniverse, rather than an artificially input parameter. This model is fully compatible withstandard quantum mechanics, open system dynamics, thermodynamics, the classical limit ofgeneral relativity, and the ΛCDM cosmological model. It only introduces two free parametersconstrained by observations (the branch number and the hierarchy activation exponent ),and provides four physical inferences with clear falsifiability
This paper proposes an ontological framework for quantum cosmology based on a single core postulate: the global state of the universe is a unique, determinate, frozen pure state in Hilbert space, encoding all possible quantum correlations. The perceived flowing spacetime, probabilities, and irreversibility arise from the reduction of this global state to local subsystems (emergence of entanglement entropy). The framework unifies the emergence of spacetime, the invariance of the speed of light, and the arrow of time. It solves the "problem of time" via the Page–Wootters mechanism, explains cyclic orthogonality through conformal cyclic cosmology, and contrasts with mainstream interpretations by its radical parsimony. Four testable conjectures are derived, covering CMB anomalies, primordial gravitational waves, Planck-scale cosmic ray correlations, and coherence anomalies in macroscopic quantum systems. The conclusions are rigorously derived in appendices using de Sitter group theory, holographic entropy bounds, and open quantum systems. A quantum circuit simulation verifies the scaling relation.
We propose that the unobservability of absolute scale constitutes a foundational principle of physics. Starting from the requirement that physical predictions must be invariant under rescalings of the action, we show that only phase-based quantities remain well defined. This requirement uniquely selects a complex amplitude description, leading directly to the structure of quantum mechanics, including linear superposition, Hilbert space, and the Born rule. Within this framework, the classical notion of action loses absolute meaning, and physical observables arise from invariant phase relations. Quantum mechanics is therefore not postulated, but emerges as the minimal consistent description of systems in which scale cannot be directly observed. The formal structure of quantum theory is shown to follow from this principle without additional axioms. We further demonstrate that the same principle implies the existence of a dynamical scale field, which governs the effective quantum scale and connects naturally to cosmological models with a time- dependent Planck mass. In this way, the structure of quantum mechanics and the large-scale dynamics of the Universe are linked through a common origin. This framework provides a unified perspective in which quantum behavior and cosmological evolution arise from a single underlying principle, suggesting a new approach to the relationship between fundamental physics and cosmology.
A multiscale thermodynamic model is considered, in which cosmological dynamics enforce persistent non-equilibrium conditions through recursive energy exchange across hierarchically ordered subsystems. The internal energy of each subsystem is recursively determined by energetic interactions with its subcomponents, forming a nested hierarchy extending up to cosmological scales. The total energy of the universe is assumed to be constant, imposing global consistency conditions on local dynamics. On the quantum scale, subsystems remain thermodynamically constrained in their accessible state space due to the unresolved energetic embedding imposed by higher-order couplings. As a result, quantum behavior is interpreted as an effective projection of unresolved thermodynamic interactions. In this view, the wave function serves as a mathematical representation of a subsystem's thermodynamic embedding, summarizing the unresolved energetic couplings with its environment, as shaped by recursive interactions across cosmological and microscopic scales. Phenomena such as zero-point energy and vacuum fluctuations are thereby understood as residual effects of structural energy constraints. Classical mechanics arises as a limiting case under full energetic resolution, while the quantum formalism reflects thermodynamic incompleteness. This formulation bridges statistical mechanics and quantum theory without metaphysical assumptions. It remains fully compatible with standard formalism, offering a thermodynamic interpretation based solely on energy conservation and hierarchical organization. All effects arise from scale-dependent resolution, not from violations of established physics.
Modern physics faces a constellation of foundational puzzles: the Big Bang singularity, time's arrow, dark matter and dark energy, the cosmological constant problem, fine-tuning, quantum measurement, and quantum gravity unification. This Perspective proposes a unified resolution grounded in complexity-driven selection from diverse quantum paths. Prior to the Big Bang, reality comprises a pre-temporal quantum substrate (lacking classical time coordinate but governed by unitary quantum evolution), evolving reversibly across multiple trajectories—including opposing time arrows. The Big Bang marks an emergence threshold (λ) where decoherence locks spacetime parameters, yielding our classical universe as a "survivor" of local emergence rather than a closed totality. Dark matter and dark energy represent unevolved quantum paths—residuals exerting gravitational influence without full manifestation. This framework reframes cosmology as the study of layered emergence, dissolving "why" questions into "when/how" selection dynamics, with testable predictions in CMB perturbations, quantum decoherence experiments, and gravitational wave observations. By shifting from reductionism to emergentism, it suggests a universal pattern: threshold-gated emergence from diverse substrates, applicable from the cosmos to consciousness.
We develop a complete theoretical framework for open quantum systems coupled to scale-invariant environments. We show that such environments are universally described by unparticle baths characterized by a single scaling dimension dU. This work provides the proof of the uniqueness theorem, the formalism of the resulting non-Markovian dynamics, and applications to several physical systems.
From the uniqueness theorem, we derive the non-Markovian memory kernels, the exact noise kernel including vacuum and thermal contributions, and a fractional generalization of the Caldeira-Leggett master equation for arbitrary dU. The scaling dimension governs a rich phase structure, including a thermalization transition at dU=3/2, the Ohmic boundary at dU=2, and a decoherence transition at dU=5/2 in the thermal regime, beyond which long-time quantum coherence is protected.
Three realizations are studied. For the quantum Ising model at criticality, coupling to the energy operator in (1+1) dimensions gives dU=3/2, producing 1/f noise, while the (2+1)D case yields dU≈1.413 from the conformal bootstrap. In inflationary cosmology, massless scalar and graviton baths in de Sitter spacetime give dU=2, predicting linear decoherence growth consistent with the quantum-to-classical transition. For high-energy astrophysical neutrinos, the decoherence rate Γdecoh∝B(E,TU)L5−2dU provides an observable signature of the scaling dimension.
We also compare the framework with Caldeira-Leggett and Lindblad approaches, analyze the validity regimes, and discuss experimental implications for trapped-ion simulators, neutrino telescopes, and superconducting qubits.
The incompatibility between quantum mechanics and relativity is not a lack of technical details, but a fundamental one—they are each built on distinct local invariants: quantum mechanics relies on gauge invariance, while relativity is based on Lorentz invariance. Starting from different mountain feet, they naturally cannot converge at the summit. What physicists are truly seeking is a global, absolute, and simple invariant—one that can govern all physical phenomena and serve as the common source of all physical laws.This paper proposes the Axiom of Cosmic Uniqueness: all events, physical states, particle configurations, and interaction relationships in the universe are strictly unique, and there are no two identical forms of existence. From the perspective of group theory, this axiom is the ultimate invariant that physicists have long pursued—because the attribute of "everything is unique" remains unchanged regardless of any transformation applied (temporal evolution, spatial translation, rotation, gauge transformation, etc.).Based on this single axiom, this paper argues that:· The essence of time is the sequential unfolding of unique states, and the unidirectionality of the arrow of time is a direct inference of uniqueness;· The essence of space is the topological structure of causal correlations between unique events;· Causality possesses absolute necessity, and the "randomness" in quantum mechanics is a cognitive limitation rather than physical reality;· Probability has no physical reality and is purely an instrumental approximation under cognitive limitations—because the definition of probability relies on "repeatable experiments", a premise negated by the Axiom of Cosmic Uniqueness;· The paradox of the origin of life is thus resolved: the origin of life has already occurred, and no probabilistic explanation is needed under the Axiom of Cosmic Uniqueness—the so-called "extremely low probability" is a pseudo-problem arising from the misapplication of the concept of probability to unique historical events.This axiom requires no presupposition of any physical laws, particle properties, or spacetime frameworks, and achieves self-consistency solely through ontological logic. It is a more fundamental global invariant than Lorentz invariance and gauge invariance, and can govern the core laws of classical physics, quantum mechanics, relativity, and cosmic evolution—for all of them are branches growing from this common source.