Heads or tails in zero gravity: an example of a classical contextual "measurement"

TL;DR

This paper illustrates how a classical coin flip in zero gravity can serve as an example of contextual measurement, drawing parallels with quantum spin measurements and clarifying the classical-quantum analogy.

Contribution

It introduces a classical example demonstrating contextual measurement, analogous to quantum spin measurement, and explains this analogy through the de Broglie-Bohm interpretation.

Findings

Coin orientation is a continuous variable before measurement.

The catch acts as a contextual measurement producing a discrete outcome.

The analogy with quantum spin measurements is clarified through the de Broglie-Bohm interpretation.

Abstract

Playing the game of heads or tails in zero gravity demonstrates that there exists a contextual "measurement" in classical mechanics. When the coin is flipped, its orientation is a continuous variable. However, the "measurement" that occurs when the coin is caught by clapping two hands together gives a discrete value (heads or tails) that depends on the context (orientation of the hands). It is then shown that there is a strong analogy with the spin measurement of the Stern-Gerlach experiment, and in particular with Stern and Gerlach's sequential measurements. Finally, we clarify the analogy by recalling how the de Broglie-Bohm interpretation simply explains the spin "measurement".