超导电路与体声波谐振器组成的量子iSWAP门方案

Scheme of Quantum iSWAP Gate Composed of Superconducting Circuits and Bulk Acoustic Wave Resonator

高保真度量子门的物理实现是量子计算和量子通信的关键技术之一。根据电路量子声动力学和量子电动力学,提出了由两个具有较长相干时间的超导transmon qubit和一个具有高机械品质因数的薄膜体声波谐振器组成的量子门方案,体声波谐振器起到类似微波光子通道的作用,使两个transmon qubit之间实现量子态交互。该文先用Butterworth-van Dyke模型分析体声波谐振器在方案中的等效电路,构建系统的量子化哈密顿量,再用二能级原子-声子混合量子态形式编码系统的量子态,通过调节外磁场来调控系统的输入态,系统的输出态可通过测量模块得到。在Jaynes-Cummings模型下,该系统能完成具有高保真度的量子相位交换(iSWAP)门操作。

The physical implementation of quantum gates with high fidelity is one of the key technologies of quantum computation and quantum communication.Based on the circuit quantum electrodynamics and circuit quantum acoustodynamics theory,a quantum gate scheme composed of two superconducting transmon qubits with long coherence time and a film bulk acoustic wave resonator(FBAR)with high mechanical quality factor is proposed in this paper.The bulk acoustic resonator acts as a microwave photon channel,which enables quantum state exchange between two transmon qubits.In this paper,the equivalent circuit of bulk acoustic resonator is analyzed by the Butterworth Van Dyke model,and the quantized Hamiltonian of the system is constructed,then the quantum state of the system is encoded in the form of two-level atom-phonon mixed quantum state.The input state of the system is controlled by adjusting the external magnetic field,and the output state of the system can be obtained by the measurement module.Under the Jaynes-Cummings model,the system can complete quantum iSWAP gate operation with high fidelity.