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Quantum Coherence and Nonclassicality from τ -Phase Statistics: From Variance Laws to Characteristic Functions

Bahman Masarratbakhsh

Published Apr 6, 2026• 0 citations
Publisher

Abstract

Phase-based quantum simulation framework (QuTiP/Qiskit) exploring coherence, entanglement, and Bell nonclassicality using a $\tau$-field model. Results show that simple observables follow phase variance laws, while complex correlations (e.g., CHSH) require full phase-distribution (characteristic function) descriptions. Fully reproducible.

DOI
10.5281/zenodo.19433171

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•Mar 31, 2026•0 citations
Phase-based quantum simulation framework (QuTiP/Qiskit) exploring coherence, entanglement, and Bell nonclassicality using a τ\tauτ-field model. Results show that simple observables follow phase variance laws, while complex correlations (e.g., CHSH) require full phase-distribution (characteristic function) descriptions. Fully reproducible.
We report a statistically significant anomaly in quantum coherence measurements from 580 IBM Quantum jobs: Bell state fidelity varies periodically with job execution time modulo a characteristic period τ0 = 46 μs. Jobs executed at 'τ-aligned' phases show 1.81x higher mean fidelity than anti-aligned phases (p < 10^-14, Cohen's d = 1.65). This effect cannot be explained by standard Markovian decoherence. We present a phenomenological Lagrangian incorporating a non-Markovian memory field that predicts F(T) = F0 e^(-Γ T) (1 + ε cos(ω_τ T - θ_lock)), consistent with observations. Bayesian model comparison yields strong evidence (BF = 28) for the oscillatory model over exponential decay.
Although variance, as one of the most fundamental and ubiquitous quantities in quantifying uncertainty, has been widely used in both classical and quantum physics, there are still new applications awaiting exploration. In this work, by interchanging the roles of the state variable and the observable variable, i.e., by formally regarding any state as an observable (which is rational because any state is a priori a Hermitian operator ) and considering the average variance of this state (now in the position of an observable ) in all spin coherent states, we introduce a quantifier of spin nonclassicality with respect to a resolution of identity induced by spin coherent states. This quantifier is easy to compute and it admits various operational interpretations, such as the purity deficit, the Tsallis 2-entropy deficit, and the squared norm deficit between the Wigner function and the Husimi function. We reveal several intuitive properties of this quantifier, connect it to the phase-space distribution uncertainty, and illustrate it with some prototypical examples. Various extensions are further indicated.
Two basic ingredients in the quantum formalism are the concepts of states and observables, and apart from the average value (which includes the Born probability as a paramountly important case), the variance is the most fundamental and prominent quantity arising from the coupling of a state and an observable. Given the simplicity and ubiquity of the variance, it seems surprising that we can still exploit the variance to gain conceptually different insight into the quantum substratum. The purpose of the present work is to advocate the following idea: By inputting a general quantum state as the observable in the variance and incorporating a resolution of identity induced by coherent states, we obtain a mathematically simple and physically intuitive method for quantifying nonclassicality. We reveal its fundamental properties and highlight its connection with phase-space quantification of nonclassicality. The idea further suggests a whole family of appealing quantifiers of nonclassicality involving deep mathematical subtlety and an intriguing conjecture with physical significance. Some prototypical examples are worked out to illustrate the concept. This approach of regarding states as observables presents an opportunity for investigating quantum features from an alternative perspective of uncertainty.
Many solid-state quantum platforms do not permit sharp, projective measurements but instead yield continuous voltage or field traces under weak, non-demolition readout. In such systems, standard Bell tests based on dichotomic projective measurements are not directly applicable, raising the question of how quantum nonlocality can be certified from continuous time-series data. Here we develop a general theoretical framework showing that Bell-CHSH inequality violation can be extracted from continuous, non-projective measurements without assuming any specific collapse model or phase distribution. We show that sufficiently long continuous measurements of a single entangled pair sample its internal phase-probability structure, enabling effective dichotomic observables to be constructed through phase-sensitive projections and coarse-graining. The resulting Bell correlator is governed by two experimentally accessible resources: intrinsic single-qubit phase spread and nonlocal phase locking between qubits. We benchmark the resulting estimator against conventional projective-measurement CHSH tests implemented via quantum-circuit simulations using Qiskit, finding quantitative agreement in the Bell-violating regime without parameter fitting. Classical deterministic correlations cannot violate the CHSH bound, whereas quantum phase-locked systems recover the nonlinear angular dependence characteristic of entanglement. Our results provide a practical route to demonstrating Bell nonlocality in platforms where measurements are inherently continuous and weak.
Version 1.0 (March 2026) We demonstrate that CHSH Bell inequality violations emerge naturally in the Lattice Field Medium (LFM) framework when measurement is modeled as a non-separable interaction with a shared wave state. The CHSH parameter S = 2.829 matches the Tsirelson bound (2√2 = 2.828) to 0.04% — without injecting quantum mechanics, nonlocal signaling, hidden variables, or superdeterminism. Four measurement models compared (1,000,000 trials each, seed=42): Model Description S Value Interpretation A Local deterministic phase readout 2.000 Classical bound (exact) B Local probabilistic 1.416 Sub-classical C Non-separable joint sampling (LFM) 2.829 Bell violation D Analytical quantum mechanics 2.828 Tsirelson bound The key insight: In LFM, entangled particles share a common wave field governed by GOV-01 and GOV-02. Measurement is an irreducibly joint interaction with this globally coherent state — NOT independent local readout. The correlation function P(a,b) = cos²(θ_ab/2) is not postulated but emerges from the overlap integral of the measurement-perturbed field. Physical mechanism:The LFM wave field Ψ(x,t) satisfies GOV-01 (Klein-Gordon lattice equation). Two spatially entangled solitons share a single non-factorizable wave function. When a measurement interaction is modeled as a joint projection onto the full bipartite state, the resulting CHSH correlations acquire the cos²(θ/2) dependence characteristic of the Tsirelson bound. Local models A and B cannot access the cross-term — they are limited to S ≤ 2 by construction. Significance: This result closes the last remaining gap (IT-05: Entanglement / Bell inequality) in the LFM Physics Equation Emergence Catalog, achieving 100% effective coverage of all 208 cataloged physics equations across 16 domains — zero verified gaps remaining. The catalog entry IT-05 has been upgraded from GAP/CONDITIONAL to DERIVED/NOVEL. Contents: manuscript.pdf — Main paper (LaTeX compiled) experiments/bell_chsh_experiment.py — Reproducible experiment (numpy only, no dependencies) experiments/summary.json — Machine-readable results figures/fig_bell_chsh_comparison.png — S-value comparison across four models figures/fig_bell_correlations.png — Correlation functions by model zenodo_v1.0/ — Complete distribution package Reproducibility: python experiments/bell_chsh_experiment.py (requires numpy only). Results are fully deterministic. Related work: LFM-PAPER-045 (full framework reference, v26.0), LFM-PAPER-065 (electromagnetism from phase), LFM-PAPER-047 (spin-1/2 emergence from Lorentz symmetry). Falsifiable: The non-separable measurement model makes a specific prediction — local models always yield S ≤ 2 regardless of field amplitude; only joint-projection models reach S ≈ 2√2. This is experimentally distinguishable from standard QM only at the level of the measurement interaction model, not the S-value itself.