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Emergent Quantum Dynamics from Interacting Semiclassical Universes with Variable Gravitational Coupling

Andrew Kiruluta

Published Jan 8, 2026• 0 citations
Publisher

Abstract

Abstract We propose a covariant multiverse framework in which quantum phenomena arise effectively for observers restricted to a single semiclassical universe. Each universe is endowed with a classical Lorentzian metric and a scalar--tensor sector that realizes a spacetime- and age-dependent gravitational coupling \(G(x,\tau)\), where \(\tau\) is a cosmic-age scalar defined with respect to a preferred cosmological congruence. Inter-universe interactions are modeled by proximity-weighted couplings that permit coherent amplitude exchange between nearby universes and by stochastic sector events that induce transitions and decoherence. For an observer in a given universe, tracing over the remaining sectors yields a reduced, open-system description that is linear and completely positive in the weak-coupling/Markovian regime, providing an explicit route to Lindblad-type generators. Metric superpositions are excluded within each universe by construction; apparent ``superpositions of geometries'' are instead identified with coherence over universe labels, with a definite classical geometry in every sector. We relate this construction to Many-Interacting-Worlds models, semiclassical and stochastic gravity, and standard open-quantum-systems techniques, and we outline phenomenological constraints from bounds on \(\dot G/G\) and proposed gravitationally mediated entanglement tests. We outline concrete next steps, including toy-model demonstrations of interference and tunneling, parameterization of scalar–tensor functions consistent with Solar-System bounds, and quantitative predictions for gravitationally mediated entanglement experiments. We supplement the conceptual framework with quantitative toy-model demonstrations (qutrit and oscillator), including plots of coherence $C_{01}(t)$, purity $\mathcal{P}(t)$, and interferometric visibility $\mathcal{V}(t)$, and we illustrate departures from Markovian LGKS dynamics via time-dependent rates in a non-Markovian variant.

DOI
10.21203/rs.3.rs-8522502/v1

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We develop an effective gravitational framework for the quantum–classical transition based on the dynamical stability of historical information. Building on previous analyses of gravitational temporal decoherence and the emergence of classical time, the present work addresses the subsequent problem of how classical histories become stable, persistent, and objectively accessible. The framework is formulated as a non-relativistic, semiclassical open-system dynamics in which gravity induces structurally constrained dissipative effects of Lindblad type. Within this setting, we introduce a stability functional that operationally characterizes which quantum states can support robust historical records and which are dynamically suppressed. The quantum–classical transition is described as a smooth, scale-dependent crossover controlled by physically meaningful parameters, rather than as a sharp boundary or interpretational postulate. The emergence of a unique classical past is shown to arise from dynamical selection: while multiple quantum histories are formally allowed, only those supported by stable physical records persist under gravitationally induced dissipation. The framework is explicitly effective in scope and does not rely on a microscopic derivation or full relativistic covariance. Instead, it identifies universal structural features that any viable fundamental theory must reproduce in the appropriate semiclassical regime. This work complements earlier studies on the emergence of classical time by providing a dynamical account of historical stability, thereby contributing to a coherent program for understanding the physical origin of classical reality.
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We propose a modification of the coupling between classical spacetime geometry and quantum matter in which the spacetime metric at each event is sourced by the stress-energy tensor evaluated on a locally decohered density matrix constructed from the causal past of that event. This replaces the usual semiclassical expectation value with a coarse-grained stress tensor derived from a decoherence channel acting on the quantum state restricted to the causal past. In this framework, decoherence determines which sector of the quantum state can influence classical spacetime geometry: coherent phase correlations remain present in the quantum state but do not source classical spacetime geometry. The resulting effective stress tensor is formulated to be covariant and compatible with the Bianchi identities under branchwise conservation. The framework avoids macroscopic-superposition paradoxes of the traditional semiclassical approach and predicts the absence of gravitationally mediated entanglement in the Bose–Marletto–Vedral protocol. Observation of such entanglement would therefore falsify the proposal.
We propose a unified framework in which quantum measurement, the arrow of time, and effective gravitational phenomena emerge from a single ontological primitive: irreversible interaction events. An event is represented operationally by a non-invertible completely positive, trace-preserving (CPTP) map, while unitary evolution and spacetime geometry are treated as effective, emergent descriptions. Time arises as a partial order induced by irreversible state-restricting events, and gravitational time dilation emerges from spatial variations in event density. An Event Equivalence Principle is introduced, according to which gravitational effects manifest universally as a rescaling of event occurrence rates, independent of particle mass. The framework yields falsifiable predictions for gravity-induced decoherence and is shown to be consistent with existing experimental bounds.
We study, within a toy model, how a thermal bath of cosmological perturbations can decohere the minisuperspace degrees of freedom of the universe, treating the perturbations as an environment in the framework of open quantum systems. Instead of tracing out the perturbations from a semiclassical ansatz for the total wave function, as in earlier approaches, we incorporate their backreaction on the background through an effective second-order coupling and derive a master equation. The model describes a spatially flat semiclassical universe during slow-roll inflation with a dust clock field, while scalar cosmological perturbations in a phenomenologically assumed thermal state constitute the environment. The master equation is non-Markovian, since the bath correlation functions do not decay in time. Within this framework, we find that, for a representative set of parameter estimates, the characteristic decoherence timescale corresponding to the thermal contribution can be shorter than the Hubble timescale. In addition, we address the question of whether the pointer-state structure induced by the decoherence in such a framework could provide a criterion for the choice of semiclassical states in quantum cosmology.
We develop a complete geometric framework in which each quantum particle possesses its own private spacetime—a world-block—constructed from Fermi–Walker coordinates. The intrinsic spatial metric on each proper-time slice is a dynamical field governed by an action with a universal stiffness constant A0. A single world-block exhibits kinematic non-locality: the metric perturbation at a point depends on the entire wavefunction through an integral relation, while maintaining dynamic locality via causal wave equations. This duality captures the essential non-locality of quantum mechanics without violating relativistic causality. When two particles interact, their world-blocks are stitched along a common boundary, forming a single compound world-block in ordinary four-dimensional spacetime. The stitching imposes local matching conditions that yield a non-separable strain field, providing a geometric account of quantum entanglement. Measurements correspond to fixing boundary conditions on one part of the compound block; the correlated outcome on the distant part is automatically determined by the shared global geometry, not by any superluminal signal. Thus, the apparent non-locality of EPR correlations is explained as a manifestation of geometric connectivity within a single 4D manifold, consistent with Bell’s theorem because the geometry itself is non-local. In the continuum limit of many overlapping blocks, coarse-graining restores an effective local description, and Newton’s law of universal gravitation emerges exactly, with Newton’s constant given by G = 3c4/(8πA0). The model offers a unified, deterministic, and fully relativistic foundation for quantum mechanics and gravity, without invoking extra dimensions or stochastic elements. Experimental signatures in ultrafast interferometry and possible connections to dark energy are discussed. The framework aligns with recent developments in emergent gravity and provides a concrete geometric realization of spacetime from quantum entanglement.