Observation of nonlinear variations in three-vertex geometric phase in two-photon polarization qutrit

TL;DR

This paper reports the experimental observation of nonlinear variations in the three-vertex geometric phase within a two-photon polarization qutrit, revealing phenomena unique to three-state quantum systems.

Contribution

It demonstrates the first experimental observation of nonlinear geometric phase variations in a three-state quantum system using a novel interferometric method.

Findings

Nonlinear variations in the three-vertex geometric phase were observed.

Rapid increases in the geometric phase occur when changing one of the states.

The method allows measurement with higher signal intensity than typical interferometers.

Abstract

We experimentally observed nonlinear variations in the three-vertex geometric phase in a two- photon polarization qutrit. The three-vertex geometric phase is defined by three quantum states, which generally forms a three-state (qutrit) system. By changing one of the three constituent states, we observed two rapid increases in the three-vertex geometric phase. The observed variations are inherent in a three-state system and cannot be observed in a two-state system. We used a time-reversed two-photon interferometer to measure the geometric phase with much more intense signals than those of a typical two-photon interferometer.