Energy-participation quantization of Josephson circuits
Energy-participation quantization of Josephson circuits
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DOI：
10.1038/s41534-021-00461-8
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发表时间：
2021-08-25
影响因子：
7.6
通讯作者：
Devoret, Michel H.
中科院分区：
文献类型：
--
作者：
Minev, Zlatko K.;Leghtas, Zaki;Devoret, Michel H.
包含非线性器件的超导微波电路，如约瑟夫森结，是新兴量子技术的领先平台。增加电路复杂性进一步需要有效的方法来计算和优化多模分布式量子电路的频谱、非线性相互作用和耗散。本文提出了一种基于电磁模式中耗散或非线性元件的能量参与比（EPR）的方法。EPR是一个介于0和1之间的数字，量化了每个元素中存储的模态能量的多少。epr服从通用约束，并由一个电磁特征模态仿真计算得到。它们直接导致系统的量子哈密顿和耗散参数。该方法提供了一种直观且易于使用的工具来量化多结电路。我们在各种约瑟夫森电路上对这种方法进行了实验测试，并在十几个样本中证明了非线性耦合和模态哈密顿参数在几个百分点内的一致性，跨越了五个数量级的能量。
Superconducting microwave circuits incorporating nonlinear devices, such as Josephson junctions, are a leading platform for emerging quantum technologies. Increasing circuit complexity further requires efficient methods for the calculation and optimization of the spectrum, nonlinear interactions, and dissipation in multi-mode distributed quantum circuits. Here we present a method based on the energy-participation ratio (EPR) of a dissipative or nonlinear element in an electromagnetic mode. The EPR, a number between zero and one, quantifies how much of the mode energy is stored in each element. The EPRs obey universal constraints and are calculated from one electromagnetic-eigenmode simulation. They lead directly to the system quantum Hamiltonian and dissipative parameters. The method provides an intuitive and simple-to-use tool to quantize multi-junction circuits. We experimentally tested this method on a variety of Josephson circuits and demonstrated agreement within several percents for nonlinear couplings and modal Hamiltonian parameters, spanning five orders of magnitude in energy, across a dozen samples.