Hidden causal loops, macroscopic realism and Einstein-Podolsky-Rosen-Bell nonlocality: forward-backward stochastic simulations

We analyze quantum measurement and entanglement by solving the dynamics of stochastic amplitudes that propagate both forward and backward in time. The model allows simulation of Einstein-Podolsky-Rosen and Bell correlations, and reveals consistency with a weak form of local realism defined after the unitary interactions determining the measurement settings. Bell violations emerge due to a breakdown of a subset of Bell's local-realism conditions. Our results elucidate how hidden causal loops can explain Bell nonlocality, without requiring retrocausality at a macroscopic level.