The Double Covariance Model: A Stochastic Reconstruction of Quantum Entangled States via Interplay of Micro-Macro Time Scales
Andrei Khrennikov
TL;DR
The Double Covariance Model (DCM) reinterprets the quantum density operator as a macro-covariance that emerges from the micro-scale cross-covariances of two classical stochastic processes across a macro time window. It provides concrete constructions to realize Bell states, arbitrary pure states, and mixed states from purely classical time series, and it derives subsystem states via a stochastic partial trace that connects marginal covariances to quantum reductions. By treating entanglement as a macro-time phenomenon driven by micro-time consistency, the DCM offers a relational, scale-aware foundation for quantum states and a stochastic realization of the partial trace. This framework bridges classical probability and quantum structure, with potential applications in quantum-like modeling across disciplines and a fresh perspective on the universality of relational fields.
Abstract
This article presents a concrete mathematical framework for the generation of entangled quantum states from classical stochastic processes. We demonstrate that any density operator $ρ_{AB}$ of a composite system can be derived from the correlations between two underlying stochastic processes, $X(t)$ and $Y(t)$, representing the random fluctuations of its subsystems. This construction utilizes a two-scale temporal scheme - micro and macro time - where quantum correlations emerge as macro-correlations derived from underlying micro-correlations. We propose the Double Covariance Model (DCM), which reproduces the fundamental properties of quantum theory by treating the quantum state as the fourth-order moment structure of an underlying classical probability space.
