Verifying multipartite entangled Greenberger-Horne-Zeilinger states via multiple quantum coherences
Ken Xuan Wei, Isaac Lauer, Srikanth J. Srinivasan, Neereja Sundaresan, Douglas McClure, D.M. Toyli, David C. McKay, Jay Gambetta, Sarah Sheldon · Physical Review A · 2020
An 18-qubit GHZ state with multipartite entanglement is prepared and measured on a 20-qubit device. The detection technique used, which is based on measuring multiple quantum coherences, is robust to noise and only requires measuring the population in the ground state.