The use of quantum processing units (QPUs) promises speed-ups for solving computational problems, but the quantum devices currently available possess only a very limited number of qubits and suffer from considerable imperfections. One possibility to progress towards practical utility is to use a co-design approach: Problem formulation and algorithm, but also the physical QPU properties are tailored to the specific application. Since QPUs will likely be used as accelerators for classical computers, details of systemic integration into existing architectures are another lever to influence and improve the practical utility of QPUs. In this work, we investigate the influence of different parameters on the runtime of quantum programs on tailored hybrid CPU-QPU-systems. We study the influence of communication times between CPU and QPU, how adapting QPU designs influences quantum and overall execution performance, and how these factors interact. Using a simple model that allows for estimating which design choices should be subjected to optimisation for a given task, we provide an intuition to the HPC community on potentials and limitations of co-design approaches. We also discuss physical limitations for implementing the proposed changes on real quantum hardware devices.
翻译:量子处理器(QPUs)的使用有望加速解决计算问题,但目前可用的量子装置只拥有数量非常有限的量子处理器(qubits),而且存在相当的缺陷。在实际效用上取得进展的一个可能性是使用共同设计方法:问题制定和算法,但物理的 QPU 属性也适合具体应用。由于QPUs 有可能被用作古典计算机的加速器,因此,系统整合到现有结构的细节是影响和改进QPUs实际效用的另一个杠杆。在这项工作中,我们研究了量子程序运行时间的不同参数对定制的混合CPU-QPU-系统的影响。我们还研究了CPU和QPU之间的通信时间影响,调整QPU设计如何影响量子和总体执行性能,以及这些因素的相互作用。我们使用一个简单的模型来估算哪些设计选择需要为特定任务作选择,我们向HPC社区提供对共同设计方法的潜力和局限性的直觉察力。我们还讨论了实施拟议的实际硬件装置变化的实际限制。