# Cross-verification of independent quantum devices

## TL;DR

This paper introduces a verification method for quantum computers that uses measurement-based quantum computation principles to ensure consistency within and across different quantum devices, enhancing trust in their results.

## Contribution

The authors develop a novel verification protocol applicable to various quantum hardware, enabling cross-device consistency checks without classical simulation.

## Key findings

- Successfully applied to five quantum processors across four physical platforms.
- Verified the correctness of up to 200 quantum circuits with up to 6 qubits.
- Demonstrated the protocol's effectiveness in real-world quantum devices.

## Abstract

Quantum computers are on the brink of surpassing the capabilities of even the most powerful classical computers. This naturally raises the question of how one can trust the results of a quantum computer when they cannot be compared to classical simulation. Here we present a verification technique that exploits the principles of measurement-based quantum computation to link quantum circuits of different input size, depth, and structure. Our approach enables consistency checks of quantum computations within a device, as well as between independent devices. We showcase our protocol by applying it to five state-of-the-art quantum processors, based on four distinct physical architectures: nuclear magnetic resonance, superconducting circuits, trapped ions, and photonics, with up to 6 qubits and 200 distinct circuits.