腔QED中利用超导量子干涉仪实现Toffoli门

基于腔量子电动力学技术,提出了利用三能级超导量子干涉仪实现Toffoli门的理论方案.利用超导量子干涉仪与腔场发生耦合,以及与外加经典脉冲发生共振跃迁来实现量子态的演化控制.该方案可以拓展到N比特Toffoli门的实现.最后,讨论了逻辑门的实验可行性,四比特Toffoli门的作用时间约为30 nm,它远小于腔衰减时间和较高能级的能量驰豫时间,从而足以实现量子态的操控.并且随着比特数的增多,Toffoli门作用时间的增幅较慢.

Realization of Toffoli Gate Based on Superconducting Quantum-Interference Devices in Cavity Quantum Electrodynamics

 A theory scheme was proposed for implementing a Toffoli gate with three-level structure superconducting quantum-interference devices (SQUID),based on the cavity quantum electrodynamics (CQED).In this proposal,quantum information was encoded into the two lower levels of a SQUID while a higher level serves as the gate manipulation.Applying the coupling of the cavity field with a SQUID,which was driven by a classical microwave pulse to control the evolution of quantum state,the scheme could be extended to achieve N-qubit Toffoli gate.And,the experimental feasibility of Toffoli gate was disscussed,and the total operation time of four-qubit Toffoli gate was computed only 30 nanometers,which was much shorter than the decay time of the cavity mode or the energy relaxation time of the higher level.And the increasing rate of the gate response time became slow with the increase of the qubit number.