Standard cosmology treats the hot-to-cold thermal evolution of the universe as a thermodynamic consequence of metric expansion, and standard quantum mechanics treats indeterminacy as ontologically primitive. A prior framework developed by the present author proposed that a final boundary condition can constrain the admissible-history ensemble of quantum cosmology, with a tiering of terminal states—trivial, structured, and computational—in which computational terminal states exert the strongest selective pruning. That earlier work left open a cosmological question: how does thermal history relate to endpoint-conditioned history selection? The present paper advances the thesis that cosmic cooling is not itself selective, but that it establishes the intermediate regime within which a computationally organized terminal condition can exert non-trivial pruning on the admissible-history ensemble. Under this reading, quantum indeterminacy functions not as the ultimate explanatory terminus of physical theory, but as the permissive admissibility substrate through which endpoint-conditioned selection operates. This is an interpretive claim about explanatory role, not a revision of the quantum formalism or a denial of its fundamentality. The paper formalizes cooling as an intermediate-regime condition, distinguishes forced from selectable features of thermal history, addresses the trivialization, teleology, anthropic, underdetermination, and fundamentality objections, and offers three candidate differential predictions concerning error-correcting substrate prevalence, the selective fine-tuning profile of constants, and the relative timing of cosmogenic transitions. The proposal is situated against Wheeler’s participatory universe, the two-state vector formalism, the transactional interpretation, Price’s time-symmetric program, Tegmark’s mathematical universe hypothesis, and Smolin’s cosmological natural selection.
Quantum mechanics permits time-symmetric formulations in which intermediate events are conditioned by both an initial state and a final boundary condition. In this paper, I develop a model of quantum history in which a final boundary condition constrains the admissible-history ensemble rather than serving as a passive terminal state. I represent the universe’s possible macroscopic development as a history graph and define an admissible subgraph by imposing a final-state condition. I then examine whether, under a history-ensemble encoding, this restriction can reduce the effective description length of realized histories relative to unconstrained branching descriptions. I argue that the informational significance of the model depends on the structure of the terminal condition. Trivial terminal states impose weak selectivity and provide little compression. Structured terminal states impose stronger constraints and better support the emergence of organized intermediate worlds. Computational terminal states impose the strongest selectivity because they favor histories that generate information-processing structures, self-replicating systems, and explicit forms of computation. On this basis, I propose that sufficiently selective computational endpoints are most naturally interpreted in agentic terms, provided agency is understood structurally rather than psychologically. The model is retrocausal in a boundary-conditioned sense but not interventionist. It excludes inconsistent histories rather than revising an already fixed past and does not require operational backward signaling. I also distinguish between maximal pruning and robustness-preserving selectivity within computational endpoint classes. I conclude that a boundary-conditioned agentic interpretation of sufficiently selective computational endpoints is not established here as empirical fact, but it is rendered a mathematically serious interpretive hypothesis by the combination of dual-boundary quantum formalism, informational pruning, and endpoint complexity analysis.
AbstractTime-symmetric and top-down approaches to quantum cosmology—most notably Aharonov’sTwo-State Vector Formalism (TSVF), Wheeler’s Participatory Anthropic Principle, andHawking-Hertog top-down cosmology—address the quantum measurement problem and cosmological fine-tuning by positing a post-selected final boundary state ⟨Φfinal| that constrainsthe early universe’s path integral. However, these frameworks face a persistent foundationalobjection: what selects the final boundary state itself? Postulating a hard-coded final microstate or an explicit teleological rule (such as “maximal integrated complexity”) merelytransfers the fine-tuning problem from the initial boundary (t = 0) to the asymptotic future (t → ∞). In this paper, we propose a non-teleological mechanism in which a uniquefinal boundary condition is dynamically bootstrapped into existence through TemporalQuantum Darwinism. Extending Zurek’s framework of Environment-Induced Superselection (einselection) and pointer-state proliferation to a bidirectional cosmic cavity, wemodel the initial and final boundaries not as externally imposed axioms, but as coupledmirrors in a time-symmetric resonant loop governed by a recursive fixed-point operator⟨Φ∗| = S[⟨Φ∗|]. We demonstrate that candidate cosmic histories dominated by intraenvironment thermal scrambling (Page-curve dynamics) fail to preserve orthogonal pointerrecords at the asymptotic horizon; consequently, their forward and backward propagatorsaccumulate random relative phases and destructively cancel out of the global WheelerDeWitt state (⟨Φscrambled|Ψ⟩ → 0). Conversely, histories whose fundamental constants support non-interacting “star-topology” broadcast channels (e.g., free-streaming photons andgravitons scattering off stable macroscopic structures) achieve massive pointer redundancy(Rδ ≫1). Because pointer states commute with the system-environment interaction Hamiltonian ([ ˆHint, ˆ Πk] = 0), they reflect coherently across the temporal cavity, amplifying viaspectral power iteration into a single, mode-locked 4D fixed-point eigenstate. This synthesis resolves the quantum measurement problem—accounting for the preferred pointerbasis, single-outcome realization without non-unitary collapse or Everettian branching, andthe Born rule—while demonstrating that complexity and observer-participancy emerge asstructural necessities for a quantum timeline to avoid destructive self-cancellation.
The origin of cosmic acceleration remains a central problem in cosmology, commonly attributed to a cosmological constant within the
ΛCDM model or to dynamical dark energy. Here, we develop an alternative approach in which acceleration emerges from quantum post-selection, a standard feature of quantum theory that is not usually incorporated into cosmological modelling. While quantum theory admits both pre-selected and post-selected ensembles, quantum cosmological models are almost exclusively formulated in terms of initial conditions. Building on previous work on post-selected quasiclassical dynamics, we construct a minimal predictive cosmological model in which post-selection and coarse-graining generate effective late-time acceleration without introducing a cosmological constant, dark energy, or modifications of general relativity. The resulting expansion history is highly constrained theoretically and depends on at most two parameters beyond standard Friedmann evolution. Confrontation with type Ia supernova and cosmic chronometer data yields statistically competitive fits while naturally avoiding the coincidence problem. The model also reproduces the standard radiation- and matter-dominated behaviour at early times and predicts a present-day jerk parameter significantly different from the
ΛCDM value. These results suggest that cosmic acceleration may arise as a macroscopic quantum cosmological effect rather than from additional cosmological fluids or modified gravitational dynamics.
This manuscript introduces a unified theoretical and empirical framework proposing that fundamental physical laws, gauge symmetries, and cosmological dynamics emerge as algorithmic resource-optimization protocols operating on an information-bounded substrate. By bridging quantum information theory, discrete lattice physics, and the Two-State Vector Formalism (TSVF), the paper transitions computational ontologies from speculative metaphysics into mathematically formalized, experimentally falsifiable physics. Key Frameworks & Contributions: Algorithmic Resource Optimization & Substrate Invariants: We map foundational principles to computational conservation laws: the Principle of Stationary Action (
δS=0) to dynamic programming; invariant light-cone speed (
c) to distributed causal latency; and quantum superposition to procedural deferred state resolution. We introduce formal substrate calibration parameters, including the information rest-mass invariant (
Mi≈2.91×10−40 kg at
300 K), holographic spacetime code distance density (
Dcode), and multi-fidelity coarse-graining bounds (
ΩMF). Algorithmic Quantum Dynamics & State-Space Pruning: We formulate Algorithmic State-Space Pruning, establishing that quantum microstate branching in open systems is biased toward algorithmically compressible states governed by a Solomonoff-Levin distribution, modifying microcanonical equiprobability in non-isolated regimes. Post-Selected Quantum Cosmology (POQCO): Within a unimodular gravity framework, late-time cosmic acceleration is derived directly from a future cosmological boundary constraint (macroscopic post-selection), eliminating the necessity of an ad hoc dark energy fluid or cosmological constant
Λ. We extract explicit cosmographic signatures, predicting an effective phantom divide crossing (
w<−1 at
z≈0.5) and a characteristic discontinuous jerk parameter (
j≈3). Four Falsifiable Empirical Protocols: To subject the framework to immediate laboratory and observational verification, we detail four experimental designs: • Quantum Computing: A 128-qubit superconducting transmon processor under ergodic Floquet drives to measure low Kolmogorov-complexity bitstring branching excesses across
106 shots. • Optomechanical Metrology: A cryogenic 4-pulse radiation-pressure Fabry-Pérot cavity coupled to a stoichiometric silicon nitride (
Si3N4) membrane to detect anomalous geometric phase shifts (
ΔΘ) from minimal-length commutator deformations. • Cold-Atom Interferometry:
87Rb atomic drift tubes utilizing non-destructive weak measurements to isolate terminal boundary-induced peak acceleration (
aweak). • Observational Cosmography: Testing POQCO kinematic transition regimes against high-redshift datasets from the Nancy Grace Roman Space Telescope, DESI Baryon Acoustic Oscillations (BAO), and Cosmic Chronometers.
The definition of entropy in both classical and quantum contexts relies on a coarse-graining of the underlying microscopic description. While this dependence is widely acknowledged, the physical constraints that determine which coarse-grainings are admissible are rarely made explicit. This issue becomes particularly acute when the universe is treated as a closed system, where no external observer or privileged level of description can be assumed. Any characterization of entropy — including claims about the low-entropy initial conditions of the universe — must then be grounded in descriptions that can be physically instantiated from within the system itself. In this work, we introduce a rigorous operational framework that establishes explicit physical selection principles over the space of admissible descriptions. We organize these criteria into necessary conditions (local accessibility and physical implementation via internal interactions) and practical sufficiency conditions (finite resource requirements anchored in Landauer’s principle, dynamical stability, and effective consistency). To demonstrate the validity of our framework, we introduce a concrete one-dimensional spin-chain toy model, illustrating how mathematically valid global partitions fail to be physically realizable due to dynamic propagation limits and informational constraints. We analyze the far-reaching implications of this restriction across three domains. In classical statistical mechanics, it limits the arbitrariness of macrostate definitions. In quantum theory, it identifies environment-induced decoherence (einselection) not merely as a formal tool, but as the objective dynamical mechanism that forces the emergence of admissible internal partitions. In cosmology, it resolves foundational circularities in the quasi-classical histories framework and reframes the thermodynamic arrow of time as a "doubly relational" property—dependent both on cosmic boundary conditions and on the material limits of internal subsystems. Our framework clarifies the operational status of entropy as an emergent property of physically instantiated descriptions within a universe that observes itself.
Description: This theoretical study revisits the interpretation of cosmological end scenarios—such as heat death and asymptotic de Sitter expansion—through the framework of quantum decoherence and energy conservation in expanding spacetimes. Rather than treating late-time cosmology as an absolute termination of physical reality, the paper distinguishes between dynamical cessation and ontological nonexistence. Using explicit calculations of decoherence rates in FLRW backgrounds, we demonstrate that when environmental particle densities dilute as (a(t)^{-3}), the integrated decoherence over infinite future time can remain finite. Under such conditions, quantum superpositions formed beyond a critical cosmological time may never fully decohere. This does not imply recoherence, cyclic cosmology, or violation of thermodynamic irreversibility. Instead, it reflects the asymptotic disappearance of environmental interaction channels that dynamically sustain classical pointer states. The work therefore proposes that late-time cosmic evolution may be more coherently interpreted as a transition from environmentally enforced classicality to a regime of dominant quantum description. The analysis integrates principles from quantum field theory in curved spacetime, decoherence theory, and cosmological expansion dynamics, offering a conceptual clarification of what is meant by a “cosmic end.” 🔹 Keywords: Quantum cosmology; Quantum superposition; Decoherence; Early universe; Late universe; Environmental noise; Quantum–classical transition; Interaction density; Foundations of physics; Conceptual physics