Computer simulation of Mermin's quantum device

Abstract

Quantum entanglement is a phenomenon that has no classical counterpart; it is not only difficult to learn but also difficult to teach. It is often an omitted or underrepresented topic in the syllabus of an introductory quantum mechanics or modern physics course. Nearly 40 years ago Mermin published a thought experiment to analyze a device consisting of a transmitter and two receivers. The receivers each had a three-position switch and two lights, one red and one green. Analysis of the operation of the device follows the predictions of quantum mechanics but only simple mathematics is employed to demonstrate the peculiar nature of quantum entanglement. A few years later he reintroduced his quantum device to a more general audience in a Physics Today article and provided another interesting interpretation. In the current paper, we make use of the recently published work in quantum information theory by Candela to have students write code to simulate the operation of the device in that article. Analysis of the device has significant pedagogical value—a fact recognized by Feynman—and simulation of its operation provides students a unique window into quantum mechanics without prior knowledge of the theory.