We provide an explicit construction of a universal gate set for continuous-variable quantum computation with microwave circuits. Such a universal set has been first proposed in quantum-optical setups, but its experimental implementation has remained elusive in that domain due to the difficulties in engineering strong nonlinearities. Here, we show that a realistic three-wave mixing microwave architecture based on the superconducting nonlinear asymmetric inductive element [Frattini et al., Appl. Phys. Lett. 110, 222603 (2017)] allows us to overcome this difficulty. As an application, we show that this architecture allows for the generation of a cubic phase state with an experimentally feasible procedure. This work highlights a practical advantage of microwave circuits with respect to optical systems for the purpose of engineering non-Gaussian states and opens the quest for continuous-variable algorithms based on few repetitions of elementary gates from the continuous-variable universal set.

中文翻译：

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通用门装置，用于微波电路的连续可变量子计算

我们为微波电路的连续变量量子计算提供了通用门集的显式构造。这种通用集首先是在量子光学设置中提出的，但是由于工程上的强非线性难以实现，因此在该领域中其实验性实现仍然难以捉摸。在这里，我们展示了一种基于超导非线性非对称感应元件的现实三波混合微波架构[Frattini等。，应用 物理 来吧 110，222603（2017）]让我们克服了这一困难。作为一个应用，我们证明了该体系结构允许通过实验上可行的程序生成立方相态。这项工作凸显了针对工程非高斯态的目的，微波电路相对于光学系统的实际优势，并开启了对基于连续变量通用集基本门的重复的连续变量算法的探索。