Barron George S, Calderon-Vargas F A, Long Junling, Pappas David P, Economou Sophia E
Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA.
National Institute of Standards and Technology, Boulder, Colorado 80305-3328, USA.
Phys Rev B. 2020;101(5). doi: 10.1103/physrevb.101.054508.
Superconducting transmon qubits are of great interest for quantum computing and quantum simulation. A key component of quantum chemistry simulation algorithms is breaking up the evolution into small steps, which naturally leads to the need for nonmaximally entangling, arbitrary CPHASE gates. Here we design such microwave-based gates using an analytically solvable approach leading to smooth, simple pulses. We use the local invariants of the evolution operator in SU(4) to develop a method of constructing pulse protocols, which allows for the continuous tuning of the phase. We find CPHASE fidelities of more than 0.999 and gate times as low as 100 ns.
超导transmon量子比特在量子计算和量子模拟方面具有极大的吸引力。量子化学模拟算法的一个关键组成部分是将演化分解为小步骤，这自然导致需要非最大纠缠的任意CPHASE门。在这里，我们使用一种解析可解的方法设计了这样基于微波的门，从而得到平滑、简单的脉冲。我们利用SU(4)中演化算符的局部不变量来开发一种构建脉冲协议的方法，该方法允许对相位进行连续调谐。我们发现CPHASE保真度超过0.999，门时间低至100纳秒。
