Realization of single-qubit positive operator-valued measurement via a one-dimensional photonic quantum walk

TL;DR

This paper demonstrates a method to implement any rank-1 single-qubit positive operator-valued measurement using a photonic quantum walk setup, enabling advanced quantum measurement capabilities.

Contribution

The authors experimentally realize generalized single-qubit measurements by mapping them onto a photonic quantum walk with projective position measurements.

Findings

Successfully implemented arbitrary rank-1 POVMs on a qubit

Demonstrated the versatility of photonic quantum walks for quantum measurements

Showed potential for scalable quantum measurement schemes

Abstract

We perform generalized measurements of a qubit by realizing the qubit as a coin in a photonic quantum walk and subjecting the walker to projective measurements. Our experimental technique can be used to realize photonically any rank-1 single-qubit positive operator-valued measure via constructing an appropriate interferometric quantum-walk network and then projectively measuring the walker's position at the final step.