Observation of four-body correlation between Kerr-nonlinear parametric oscillators

We present a new unit circuit of Kerr-nonlinear parametric oscillators (KPOs) with a four-body interaction, which enables all-to-all connections between Ising spins by using Sourlas-Lechner-Hauke-Zoller scheme [1, 2]. Because the circuit does not need a nonlinear coupler, the device fabrication and characterization are simpler than those of the unit circuit proposed in Ref. [3]. Numerical calculations indicate that the amplitude of the coupling constant can be comparable to that in the conventional circuit with a nonlinear coupler with a large Kerr coefficient. Based on the theory, we designed the circuit and demonstrate four-body correlation between KPOs by experiment. The results show that we realized four-body interactions between the KPOs while effect of other interactions is excluded in the rotating frame.



[1] N. Sourlas, Phys. Rev. Lett. 94, 070601 (2005)

[2] W. Lechner, P. Hauke and P. Zoller, Sci. Adv. 1 (2015) no.9, 1500838

[3] S. Puri, C. K. Anderson, A. L. Grimsmo and A. Blais, Nature Commun. 8, (2017) no.1, 15785