Comment on "Comment on 'On Visibility in the Afshar Two-Slit Experiment' "

TL;DR

This paper clarifies a previous discussion on a thought experiment related to quantum interference, emphasizing correct measurement characterization and agreement on the non-existence of 'which slit' information when interference occurs.

Contribution

It resolves misunderstandings about the experimental conditions needed to observe interference and clarifies the agreement on the nature of 'which slit' information in quantum experiments.

Findings

Interference can be obtained with proper detection characterization.

Measurement preserving interference prevents 'which slit' determination.

Authors agree that interference implies no genuine 'which slit' information.

Abstract

Tabish Qureshi (2010) has recently objected to an aspect of my discussion of a thought experiment by Srikanth (2001). I believe his objection is based on a misunderstanding about my presentation, but I accept responsibility for not being more clear. Here I attempt to clear up any confusion and to point out that one can indeed obtain interference in this experiment based on taking care to correctly characterize the detection process. I also emphasize that Qureshi and I are in full agreement concerning the assertion that when interference is present, there is no genuine 'which slit' information, and that in this case, the measurement necessary to preserve interference precludes determination of an actual slit of origin for the photon.