Observation of geometric phases in quantum erasers

TL;DR

This paper demonstrates how geometric phases can be observed in a quantum eraser experiment using a double-slit setup with polarized light, illustrating key quantum interference phenomena.

Contribution

It presents a straightforward experimental setup to visualize quantum interference, which includes the effects of which-path marking, quantum erasers, and geometric phases, supported by theoretical analysis.

Findings

Disappearance of fringes with which-path marking

Restoration of interference with quantum erasers

Fringe shifts due to geometric phase

Abstract

We introduce a simple experiment involving a double-slit interferometer by which one can learn basic concepts of quantum interference such as which-path marking, quantum erasers, and geometric phases. Each of them exhibits seemingly mysterious phenomena in quantum physics. In our experiment, we use the double-slit interference of visible light with the polarization as an internal state to demonstrate the disappearance of fringes by which-path marking, recovery of interference using quantum erasers, and the rapid shifting of the fringe pattern induced by the geometric phase. We also present a simple theoretical analysis of an interferometer with an internal state.