Experimental device-independent tests of quantum channels

TL;DR

This paper demonstrates experimental device-independent testing of quantum channels using photonic setups, providing a validation method that does not rely on trusting the measurement devices, thus improving quantum process characterization.

Contribution

It experimentally implements device-independent quantum channel tests, advancing beyond traditional tomography by removing assumptions about device trustworthiness.

Findings

Successful photonic implementation of device-independent quantum channel tests

Validation of quantum channels without relying on device trust

Potential for improved quantum information processing methods

Abstract

Quantum tomography is currently the mainly employed method to assess the information of a system and therefore plays a fundamental role when trying to characterize the action of a particular channel. Nonetheless, quantum tomography requires the trust that the devices used in the laboratory perform state generation and measurements correctly. This work is based on the theoretical framework for the device-independent inference of quantum channels that was recently developed and experimentally implemented with superconducting qubits in [Dall'Arno, Buscemi, Vedral, arXiv:1805.01159] and [Dall'Arno, Brandsen, Buscemi, PRSA 473, 20160721 (2017)]. Here, we present a complete experimental test on a photonic setup of two device-independent quantum channels falsification and characterization protocols to analyze, validate, and enhance the results obtained by conventional quantum process tomography. This framework has fundamental implications in quantum information processing and may also lead to the development of new methods removing the assumptions typically taken for granted in all the previous protocols.