Experimental demonstration of quantum pigeonhole paradox

TL;DR

This paper experimentally demonstrates the quantum pigeonhole paradox, showing that three photons can be arranged such that no two are in the same polarization channel, revealing counter-intuitive quantum effects.

Contribution

First experimental demonstration of the quantum pigeonhole paradox using single photons and polarization channels, clarifying its operational regime.

Findings

Quantum pigeonhole effect observed in photon polarization channels

Effect breaks down under second-order measurement

Confirms the paradox's existence and operational conditions

Abstract

We experimentally demonstrate that when three single photons transmit through two polarization channels, in a well-defined pre- and postselected ensemble, there are no two photons in the same polarization channel by weak-strength measurement, a counter-intuitive quantum counting effect called quantum pigeonhole paradox. We further show that this effect breaks down in second-order measurement. These results indicate the existence of quantum pigeonhole paradox and its operating regime.