"Quantum Interference with Slits" Revisited

TL;DR

This paper critically examines Marcella's quantum mechanical approach to slit interference, revealing that it relies on classical approximations and contains misleading arguments, thus offering no new physics beyond traditional methods.

Contribution

The paper clarifies that Marcella's method employs classical approximations and does not introduce novel quantum insights into slit interference phenomena.

Findings

Marcella's approach relies on classical approximations.

No new quantum physics is introduced.

Some quantum arguments are misleading.

Abstract

Marcella [arXiv:quant-ph/0703126] has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his calculation as if no approximations are employed. We show that he implicitly makes the same approximations found in classical treatments of interference and that no new physics has been introduced. At the same time, some of the quantum mechanical arguments Marcella gives are, at best, misleading.