Effects of gate errors in digital quantum simulations of fermionic systems
Effects of gate errors in digital quantum simulations of fermionic systems
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DOI：
10.1088/2058-9565/aad5ba
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发表时间：
2018-04
影响因子：
6.7
通讯作者：
Jan-Michael Reiner;S. Zanker;I. Schwenk;J. Leppäkangas;F. Wilhelm-Mauch;G. Schön;M. Marthaler
中科院分区：
文献类型：
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作者：
Jan-Michael Reiner;S. Zanker;I. Schwenk;J. Leppäkangas;F. Wilhelm-Mauch;G. Schön;M. Marthaler
数字量子模拟为费米子系统（如分子或晶格模型）的研究提供了令人兴奋的前景。然而，由于量子纠错仍然是遥不可及的系统的有趣的大小，一个不消失的错误率是不可避免的。本文以费米子Hubbard模型为研究对象，研究了门误差对量子系统时域演化模拟的影响。具体来说，我们考虑了随机过旋转对应用门的影响。根据实现的特定算法，这种门误差可能导致模拟无序费米子系统的时间演化，或者它们可能对应于非物理误差，例如违反粒子数守恒。我们通过模型系统的数值模拟来证实我们的分析。此外，我们还建立了栅极保真度与过旋转强度之间的关系。在此基础上，我们提供了能够以足够的精度执行的最大门数的估计。这反过来意味着，除了对模拟的最大时间的限制外，还对当前技术可以处理的系统大小进行了限制。
Digital quantum simulations offer exciting perspectives for the study of fermionic systems such as molecules or lattice models. However, with quantum error correction still being out of reach for systems of interesting size, a non-vanishing error rate is inevitable. Here, we study the influence of gate errors on simulations of the Trotterized time evolution of the quantum system with focus on the fermionic Hubbard model. Specifically, we consider the effect of stochastic over-rotations in the applied gates. Depending on the particular algorithm implemented, such gate errors may lead to a time evolution that models a disordered fermionic system, or they may correspond to unphysical errors, e.g., violating particle number conservation. We substantiate our analysis by numerical simulations of model systems. In addition we establish the relation between the gate fidelity and the strength of the over-rotations. Based on this we provide estimates for the maximum number of gates which can be performed with sufficient accuracy. This in turn implies, apart from limitations on the maximum time of the simulation, also restrictions on the system size which can be handled with present-day technology.