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arXiv · 1905.05720

Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences

Ken X. Wei·Isaac Lauer·Srikanth Srinivasan·Neereja Sundaresan·Douglas T. McClure·David Toyli·David C. McKay·Jay M. Gambetta·Sarah Sheldon
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Abstract

The ability to generate and verify multipartite entanglement is an important benchmark for near-term quantum devices devices. We develop a scalable entanglement metric based on multiple quantum coherences, and demonstrate experimentally on a 20-qubit superconducting device - the IBM Q System One. We report a state fidelity of 0.5165$\pm$0.0036 for an 18-qubit GHZ state, indicating multipartite entanglement across all 18 qubits. Our entanglement metric is robust to noise and only requires measuring the population in the ground state; it can be readily applied to other quantum devices to verify multipartite entanglement.

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Ken X. Wei, Isaac Lauer, Srikanth Srinivasan, Neereja Sundaresan, Douglas T. McClure, David Toyli, David C. McKay, Jay M. Gambetta, Sarah Sheldon. 2019-05-14. Verifying Multipartite Entangled GHZ States via Multiple Quantum Coherences. https://doi.org/10.1103/physreva.101.032343

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