Quantum Position Verification with Remote Untrusted Devices

TL;DR

This paper presents a device-independent quantum position verification protocol that uses loophole-free Bell tests to securely localize a remote party, outperforming classical localization methods significantly.

Contribution

It introduces a novel quantum position verification protocol that guarantees security without trusting hardware, demonstrated experimentally with superior localization accuracy.

Findings

Achieved 2.47 times smaller localization than classical protocols.

Localization is 4.53 times smaller than classical protocols with identical latencies.

Demonstrated secure quantum localization using loophole-free Bell tests.

Abstract

Many applications require or benefit from being able to securely localize remote parties. In classical physics, adversaries can in principle have complete knowledge of such a party's devices, and secure localization is fundamentally impossible. This limitation can be overcome with quantum technologies, but proposals to date require trusting vulnerable hardware. Here we develop and experimentally demonstrate a protocol for device-independent quantum position verification that guarantees security with only observed correlations from a loophole-free Bell test across a quantum network. The protocol certifies the position of a remote party against adversaries who, before each instance of the test, are weakly entangled, but otherwise have unlimited quantum computation and communication capabilities. Our demonstration achieves a one-dimensional localization that is 2.47(2) times smaller than the best, necessarily non-remote, classical localization protocol. Compared to such a classical protocol having identical latencies, the localization is 4.53(5) times smaller. This work anchors digital security in the physical world.