Cross-Platform Verification of Intermediate Scale Quantum Devices

TL;DR

This paper introduces a protocol for verifying and comparing quantum states across different platforms using local measurements, demonstrated with entangled 10-qubit states in a trapped ion system.

Contribution

A novel cross-platform verification protocol that measures overlaps and fidelities of quantum states using only local, classically communicated measurements.

Findings

Successfully measured experiment-theory fidelities for 10-qubit entangled states.

Demonstrated the protocol on a trapped ion quantum simulator.

Validated the effectiveness of local measurements for cross-platform quantum state verification.

Abstract

We describe a protocol for cross-platform verification of quantum simulators and quantum computers. We show how to measure directly the overlap $\textrm{Tr}\left[\rho_1 \rho_2\right]$ and the purities $\textrm{Tr}\left[\rho^2_{1,2}\right]$, and thus a fidelity of two possibly mixed quantum states $\rho_1$ and $\rho_2$ prepared in separate experimental platforms. We require only local measurements in randomized product bases, which are communicated classically. As a proof-of-principle, we present the measurement of experiment-theory fidelities for entangled $10$-qubit quantum states in a trapped ion quantum simulator.