We propose a geometric decoherence mechanism within the rotational-order unification framework built upon the Zhang Effective Metric. Stochastic zero-point fluctuations of the internal S³ orientation field generate fluctuations of the effective spacetime metric, imprinting random relative phases on quantum superpositions. The derived decoherence rate scales as M² at leading order, naturally suppressing macroscopic superpositions while preserving coherence for microscopic particles. This mechanism is qualitatively distinct from Diósi–Penrose / Károlyházy gravitational decoherence: the metric fluctuations originate from the internal fibre geometry rather than the mass distribution of the quantum system itself. The fluctuations couple only to massive matter-wave phases at leading order and do not produce photon dispersion. This work predicts a universal, shielding-insensitive noise floor for macroscopic quantum experiments.
We propose a geometric decoherence mechanism within the rotational-order unification framework built upon the Zhang Effective Metric. Stochastic zero-point fluctuations of the internal S³ orientation field generate fluctuations of the effective spacetime metric, imprinting random relative phases on quantum superpositions. The derived decoherence rate scales as M² at leading order, naturally suppressing macroscopic superpositions while preserving coherence for microscopic particles. This mechanism is qualitatively distinct from Diósi–Penrose / Károlyházy gravitational decoherence: the metric fluctuations originate from the internal fibre geometry rather than the mass distribution of the quantum system itself. The fluctuations couple only to massive matter-wave phases at leading order and do not produce photon dispersion. This work predicts a universal, shielding-insensitive noise floor for macroscopic quantum experiments.
Levitated optomechanical systems are approaching the regime where macroscopic quantum superpositions become experimentally accessible. A central question is whether gravity itself, through its unavoidable coupling to material quantum fluctuations, imposes a fundamental decoherence channel on such superpositions. Starting from two independently well-tested physical elements—the quantum vacuum fluctuations of the material energy-momentum tensor, and the weak-field linear response kernel of classical general relativity—we derive a structurally rigid scaling law for the gravitational decoherence rate: \Gamma \propto G M^2 d^2 / (\hbar L^3) \cdot \Phi(l_*/L). The exponents and dependence on mass M, superposition separation d, and object size L are fixed entirely by dimensional analysis and the semiclassical field equations, without tunable parameters. The overall amplitude is set by a single phenomenological input—the ultraviolet cutoff scale l_* of the effective geometric noise. Identifying l_* with the Planck length yields \Phi \sim \mathcal{O}(1) and a decoherence rate of order 1\,\text{Hz} for nanoparticles with M \sim 10^{-14}\,\text{kg}, d \sim 10^{-7}\,\text{m}, and L \sim 10^{-6}\,\text{m}, placing the prediction within the foreseeable sensitivity window of next-generation levitated optomechanical setups. We provide explicit falsification conditions, a three-path staged verification strategy that does not require simultaneous optimisation of all parameters, and operational signatures—including a distinctive pure-dephasing channel without energy relaxation—that distinguish this mechanism from environmental noise, zero-temperature electromagnetic vacuum fluctuations, and the Diósi-Penrose model.
Why do macroscopic objects appear classical? The Diósi-Penrose conjecture proposes that the classical gravitational self-energy directly determines the decoherence rate for spatial superpositions. We present an exposition and experimental analysis of this hypothesis, interpreting the mechanism in terms of environmental decoherence compatible with unitarity. We identify four distinctive experimental signatures that no other decoherence mechanism exhibits simultaneously. Part of the Quantum-Geometric Duality series (Paper A).
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.
This paper develops the gravitational decoherence sector of MonoField Theory, a framework in which physical reality is described by a single classical field (\Phi: \mathbb{R}^{3,1} \to S^3) and matter appears as Skyrmion solitons. Only the Skyrmion centre-of-mass position is quantized, while the ripple sector of (\Phi) acts as a classical stochastic environment. Using standard open quantum systems methods, the work derives the structural form of the decoherence rate (\gamma \sim (G M^2/\hbar R),Y), identifies a microscopic cutoff scale (\ell_0) that suppresses short-distance correlations, and obtains a testable scaling law (\gamma \propto R^{5-\alpha}) at fixed density, in contrast to the Diósi–Penrose prediction (\gamma \propto R^5). The paper maps the phenomenological parameter space ((\ell_0, \alpha, T_{\mathrm{eff}})), discusses consistency with existing matter interferometry, and outlines how future nanoparticle experiments can constrain or measure the effective exponent (\alpha).
The fact that gravitational environments cannot be shielded (since gravity is universal) makes them of great theoretical interest to decoherence mechanisms and to the quantum-to-classical transition. While past results seemed to indicate that graviton-induced decoherence of spatial superpositions happens only for macroscopic systems, recently it was shown that this mechanism can be enhanced through the system's own dynamical internal structure. In this work, we extend this analysis by including the interaction with a classical Newtonian potential. We show that, although the graviton bath alone dominates the mechanism for short times compared to a timescale established by the size of the quantum spatial superposition, the interaction between the gravitons and the internal degrees of freedom of the system renders decoherence inevitable in the long-time limit, even for microscopic masses. We also show that this mechanism is slightly slowed down by the interplay with the classical Newtonian potential, which, for systems without dynamical internal degrees of freedom, can even lead to recoherence-like behaviour, at least in principle.
We present a derivation of quantum decoherence rates within a vacuum pressure gradient model of gravity, in which local vacuum density decreases near massive objects according to rho_vac(r) = rho_0*(1 - 2GM/rc^2). This model predicts that decoherence rates are suppressed near massive objects — in direct opposition to the Diosi-Penrose model, which predicts enhancement near mass. The sign reversal produces a measurable fractional difference of 3GM/rc^2 between the two model predictions. We identify that quantum decoherence and macroscopic void decay are the same physical process at different scales, both governed by local vacuum bubble density eroding void-pair boundaries. We propose an experimental protocol using atomic interferometry at varying gravitational potentials, achievable with existing space-based platforms, that discriminates between this model and Diosi-Penrose by sign alone. For trapped ion qubits with coherence times of order 100 seconds, the predicted fractional improvement between Earth surface and the International Space Station is 8.22 x 10^-11.UFFT Paper #1. Part of the Unified Foam Field Theory (B + V = D). Zero free parameters. GitHub: https://github.com/WebEnvy/UnifiedFoamFieldTheory