Experimental gate operation of entangled cat states in two Kerr parametric oscillators*

 A Kerr parametric oscillator (KPO) is parametrically driven weakly nonlinear oscillator and is one of the promising devices for quantum computing, quantum simulation and error correction because cat states can be generated and stabilized easily in this system [1]. We present our experimental efforts towards two-qubit gate operations for cat states in two-dimensional superconducting KPOs. The two KPOs are capacitively coupled, and the detuning between them is much larger than the coupling strength. The gate operation is performed by applying a parametric drive to one of the KPOs [2]. A tunable coupler is not required as our KPO supports three-wave mixing by itself. We create entangled cat states by using this gate operation. We will present experimental results on two-cat-qubit gate operations. This works will be the first step towards practical scaling for continuous variable quantum computation. 

[1] Grimm, A., Frattini, N.E., Puri, S. et al. Stabilization and operation of a Kerr-cat qubit. Nature 584, 205–209 (2020)

[2] Hiroomi Chono, Two-qubit gate using conditional driving for highly detuned Kerr-nonlinear parametric oscillators, Phys. Rev. Research 4, 043054 (2022)