It is vital to minimize the impact of errors for near-future quantum devices that will lack the resources for full fault tolerance. Two quantum error mitigation (QEM) techniques have been introduced recently, namely, error extrapolation [Y. Li and S.?C. Benjamin, Phys. Rev. X 7, 021050 (2017) ; K. Temme et?al. , Phys. Rev. Lett. 119, 180509 (2017) ] and quasiprobability decomposition [K. Temme et?al. , Phys. Rev. Lett. 119, 180509 (2017) ]. To enable practical implementation of these ideas, here we account for the inevitable imperfections in the experimentalist’s knowledge of the error model itself. We describe a protocol for systematically measuring the effect of errors so as to design efficient QEM circuits. We find that the effect of localized Markovian errors can be fully eliminated by inserting or replacing some gates with certain single-qubit Clifford gates and measurements. Finally, having introduced an exponential variant of the extrapolation method we contrast the QEM techniques using exact numerical simulation of up to 19 qubits in the context of a “ swap ” test circuit. Our optimized methods dramatically reduce the circuit’s output error without increasing the qubit count.
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机译：最大限度地减少对近期量子器件的误差的影响至关重要，这将缺乏全容错的资源。最近介绍了两个量子误差缓解（QEM）技术，即误差外推[Y.李和S.?C。本杰明，物理。 Rev. x 7,021050（2017年）; K. Temme et？al。 ，物理。 rev. lett。 119,180509（2017）]和Quasiprobability分解[K. temme et？al。 ，物理。 rev. lett。 119,180509（2017）]。为了实现这些想法的实际实施，我们在这里考虑了实验主义者对错误模型本身的知识的必然不完美之处。我们描述了一种用于系统地测量误差效果的协议，以设计高效的QEM电路。我们发现，通过插入或更换具有某些单QUBBIT夹闸门和测量的一些栅极可以完全消除局部马尔可夫误差的效果。最后，引入了外推方法的指数变型，我们在“交换”测试电路的背景下使用高达19个Qubits的精确数值模拟对比QEM技术。我们的优化方法显着降低了电路的输出误差而不增加量子位计数。
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