Measuring evolution of a photon in an interferometer with spectrally-resolved modes

TL;DR

This paper investigates photon behavior in a nested interferometer using spectrally-resolved detection, challenging previous claims of counterintuitive photon trajectories and contributing to the debate on quantum interpretations.

Contribution

It provides an alternative experimental implementation that shows no counterintuitive photon behavior, questioning prior interpretations based on the two-state vector formalism.

Findings

No counterintuitive photon behavior observed with spectrally-resolved detection

Supports alternative explanations for photon trajectories in interferometers

Challenges previous results suggesting unusual photon paths

Abstract

In the year 2013, Danan et al. published a paper [Phys. Rev. Lett. 111, 240402 (2013)] demonstrating a counterintuitive behavior of photons in nested Mach-Zehnder interferometers. The authors then proposed an explanation based on the two-state vector formalism. This experiment and the authors' explanation raised a vivid debate within the scientific community. In this paper, we contribute to the ongoing debate by presenting an alternative experimental implementation of the Danan et al. scheme. We show that no counterintuitive behavior is observed when performing direct spectrally-resolved detection.