Liu Tong, Zhang Yang, Guo Bao-Qing, Yu Chang-Shui, Zhang Wei-Ning
Opt Express. 2019 Sep 16;27(19):27168-27182. doi: 10.1364/OE.27.027168.
The principle of superposition is a key ingredient for quantum mechanics. A recent work [Phys. Rev. Lett.116, 110403 (2016)10.1103/PhysRevLett.116.110403] has shown that a quantum adder that deterministically generates a superposition of two unknown states is forbidden. Here we consider the implementation of the probabilistic quantum adder in the 3D cavity-transmon system. Our implementation is based on a three-level superconducting transmon qubit dispersively coupled to two cavities. Numerical simulations show that high-fidelity generation of the superposition of two coherent states is feasible with current circuit QED technology. Our method also works for other physical systems such as two optical cavities coupled to a three-level atom or two nitrogen-vacancy center ensembles interacted with one three-level superconducting flux qubit.
叠加原理是量子力学的关键要素。最近的一项工作[《物理评论快报》116, 110403 (2016)10.1103/PhysRevLett.116.110403]表明，确定性地生成两个未知态叠加的量子加法器是被禁止的。在此，我们考虑在三维腔-跨导子系统中实现概率性量子加法器。我们的实现基于一个与两个腔色散耦合的三能级超导跨导子量子比特。数值模拟表明，利用当前的电路量子电动力学技术，高保真地生成两个相干态的叠加是可行的。我们的方法也适用于其他物理系统，例如与一个三能级原子耦合的两个光学腔，或与一个三能级超导磁通量子比特相互作用的两个氮空位中心系综。
