A widely-used quantum programming paradigm comprises of both the data flow and control flow. Existing quantum hardware cannot well support the control flow, significantly limiting the range of quantum software executable on the hardware. By analyzing the constraints in the control microarchitecture, we found that existing quantum assembly languages are either too high-level or too restricted to support comprehensive flow control on the hardware. Also, as observed with the quantum microinstruction set QuMIS, the quantum instruction set architecture (QISA) design may suffer from limited scalability and flexibility because of microarchitectural constraints. It is an open challenge to design a scalable and flexible QISA which provides a comprehensive abstraction of the quantum hardware. In this paper, we propose an executable QISA, called eQASM, that can be translated from quantum assembly language (QASM), supports comprehensive quantum program flow control, and is executed on a quantum control microarchitecture. With efficient timing specification, single-operation-multiple-qubit execution, and a very-long-instruction-word architecture, eQASM presents better scalability than QuMIS. The definition of eQASM focuses on the assembly level to be expressive. Quantum operations are configured at compile time instead of being defined at QISA design time. We instantiate eQASM into a 32-bit instruction set targeting a seven-qubit superconducting quantum processor. We validate our design by performing several experiments on a two-qubit quantum processor.
翻译:一个广泛使用的量子编程模式由数据流和控制流组成。 现有的量子硬件无法很好地支持控制流, 大大限制了可执行的量子软件范围。 通过分析控制微结构的制约因素, 我们发现现有的量子组装语言要么太高, 要么太限制, 无法支持硬件的全面流控。 另外, 正如量子缩微图集所观察到的 QIMIS, 量子指令集结构的设计可能因微结构制约而具有有限的可缩放性和灵活性。 设计一个可缩放和灵活的QISA是一个公开的挑战, 以提供量子硬件的全面抽象。 在本文中, 我们提议一个可执行的QISA, 称为eQASM, 可以用量子组语言翻译, 支持全面的量子程序流控, 并且以量子控缩放微结构执行。 有了高效的时间规格, 单项- 多比特执行, 以及一个非常长的读写字的QISA, eQSMA 将一个更精确的缩略图化操作 放在了 QAS 的精确度 。 我们定时标定的QAQAQAQA, 的精确级定定的精确度, 。 我们定定定定定的精确级的精确度, 。