Fast adiabatic qubit gates using only σz control
Fast adiabatic qubit gates using only σz control
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DOI：
10.1103/physreva.90.022307
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发表时间：
2014-08-08
影响因子：
2.9
通讯作者：
Geller, Michael R.
中科院分区：
文献类型：
--
作者：
Martinis, John M.;Geller, Michael R.
在超导 Xmon 跨蒙量子比特中，依靠 |11 > 和 |02 > 状态之间的绝热相互作用，受控相门的保真度达到了 99.4%。在此，我们解释了这一协议背后的理论概念，它基于状态误差到功率谱密度的非线性映射理论和最佳窗口函数的使用，只需控制哈密顿的 sigma z 就能实现快速栅极时间。通过在傅立叶基础上给出的解决方案，可以证明在任意状态变化和控制信号带宽有限的实际情况下，优化是简单易行的。我们发现，对于现实的控制波形，可以轻松实现低于 10(-4) 的误差。
A controlled-phase gate was demonstrated in superconducting Xmon transmon qubits with fidelity reaching 99.4%, relying on the adiabatic interaction between the |11 > and |02 > states. Here we explain the theoretical concepts behind this protocol, which achieves fast gate times with only sigma z control of the Hamiltonian, based on a theory of nonlinear mapping of state errors to a power spectral density and use of optimal window functions. With a solution given in the Fourier basis, optimization is shown to be straightforward for practical cases of an arbitrary state change and finite bandwidth of control signals. We find that errors below 10(-4) are readily achievable for realistic control wave forms.