Classical, quantum and event-by-event simulation of a Stern-Gerlach experiment with neutrons

TL;DR

This paper compares classical, quantum, and event-based simulations of a neutron Stern-Gerlach experiment, showing that a modified classical model can replicate quantum-like results without invoking quantum mechanics.

Contribution

It introduces a simple modification to the classical Newtonian model that enables it to produce quantum-like outcomes in neutron spin experiments.

Findings

Classical and quantum models produce similar splitting patterns.

A modified classical model can replicate quantum results.

Event-based simulation aligns qualitatively with experimental data.

Abstract

We present a comprehensive simulation study of the Newtonian and quantum model of a Stern-Gerlach experiment with cold neutrons.By solving Newton's equation of motion and the time-dependent Pauli equation, for a wide range of uniform magnetic field strengths, we scrutinize the role of the latter for drawing the conclusion that the magnetic moment of the neutron is quantized. We then demonstrate that a marginal modification of the Newtonian model suffices to construct, without invoking any concept of quantum theory, an event-based subquantum model that eliminates the shortcomings of the classical model and yields results that are in qualitative agreement with experiment and quantum theory. In this event-by-event model, the intrinsic angular momentum can take any value on the sphere, yet, for a sufficiently strong uniform magnetic field, the particle beam splits in two, exactly as in experiment and in concert with quantum theory.