Multipartite Entanglement in a Microwave Frequency Comb
Shan W. Jolin, Gustav Andersson, J. C. Rivera Hernández, Ingrid Strandberg, Fernando Quijandría, José Aumentado, Riccardo Borgani, Mats O. Tholén, David B. Haviland · Physical Review Letters · 2023
Significant progress has been made with multipartite entanglement of discrete qubits, but continuous variable systems may provide a more scalable path toward entanglement of large ensembles. We demonstrate multipartite entanglement in a microwave frequency comb generated by a Josephson parametric amplifier subject to a bichromatic pump. We find 64 correlated modes in the transmission line using a multifrequency digital signal processing platform. Full inseparability is verified in a subset of seven modes. Our method can be expanded to generate even more entangled modes in the near future.