Cross-Platform Verification of Intermediate Scale Quantum Devices


Andreas Elben, Benoît Vermersch, Rick Van Bijnen, Christian Kokail, Tiff Brydges, Christine Maier, Manoj K. Joshi, Rainer Blatt, Christian F. Roos, and Peter Zoller. 2020. “Cross-Platform Verification of Intermediate Scale Quantum Devices.” Physical Review Letters, 124, Pp. 010504.


We describe a protocol for cross-platform verification of quantum simulators and quantum computers. We show how to measure directly the overlap Tr[$\rho$1$\rho$2] and the purities Tr[$\rho$1,22], 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.