A classical optical approach to the `non-local Pancharatnam-like phases' in Hanbury-Brown-Twiss correlations

TL;DR

This paper demonstrates that classical statistical methods suffice to explain nonlocal geometric phases in intensity interferometry, clarifies misconceptions about their quantum interpretation, and proposes a simpler experimental setup.

Contribution

It shows that classical treatments are adequate for nonlocal phases in intensity interferometry and clarifies that these phases are not true Pancharatnam phases, proposing a simpler experimental configuration.

Findings

Classical statistical approach explains observed effects.

Phase angles do not correspond to Pancharatnam phases.

A simpler Mach-Zehnder setup can observe similar effects.

Abstract

We examine a recent proposal to show the presence of nonlocal Pancharatnam type geometric phases in a quantum mechanical treatment of intensity interferometry measurements upon inclusion of polarizing elements in the setup. It is shown that a completely classical statistical treatment of such effects is adequate for practical purposes. Further we show that the phase angles that appear in the correlations, while at first sight appearing to resemble Pancharatnam phases in their mathematical structure, cannot actually be interpreted in that manner. We also describe a simpler Mach-Zehnder type setup where similar effects can be observed without use of the paraxial approximation.