Experimental Quantum Private Queries with linear optics

TL;DR

This paper introduces a new quantum private query protocol using linear optics, enabling secure database queries with privacy tests, and demonstrates a proof-of-principle experimental implementation.

Contribution

It presents a novel quantum private query algorithm compatible with linear optical systems, combining simplicity and privacy features.

Findings

Successful proof-of-principle experimental realization

Utilizes photon momentum and polarization for qubits

Demonstrates feasibility of linear optical quantum private queries

Abstract

The Quantum Private Query is a quantum cryptographic protocol to recover information from a database, preserving both user and data privacy: the user can test whether someone has retained information on which query was asked, and the database provider can test the quantity of information released. Here we introduce a new variant Quantum Private Query algorithm which admits a simple linear optical implementation: it employs the photon's momentum (or time slot) as address qubits and its polarization as bus qubit. A proof-of-principle experimental realization is implemented.