The quantum instruction set (QIS) is defined as the quantum gates that are physically realizable by controlling the qubits in a quantum hardware. Compiling quantum circuits into the product of the gates in a properly-defined QIS is a fundamental step in quantum computing. We here propose the \R{quantum variational instruction set (QuVIS)} formed by flexibly-designed multi-qubit gates for higher speed and accuracy of quantum computing. The controlling of qubits for realizing the gates in a QuVIS are variationally achieved using the fine-grained time optimization algorithm. Significant reductions on both the error accumulation and time cost are demonstrated in realizing the swaps of multiple qubits and quantum Fourier transformations, compared with the compiling by the standard QIS such as \RR{the quantum microinstruction set} (QuMIS, formed by several one- and two-qubit gates including the one-qubit rotations and controlled-NOT gate). With the same requirement on quantum hardware, the time cost by \R{QuVIS} is reduced to be less than one half of that by QuMIS. Simultaneously, the error is suppressed algebraically as the depth of the compiled circuit is reduced. As a general compiling approach with high flexibility and efficiency, \R{QuVIS} can be defined for different quantum circuits and adapt to the quantum hardware with different interactions.

翻译：量子指令集（QIS）定义为通过控制量子硬件中的量子比特可物理实现的量子门。将量子电路编译至适当定义QIS中的门乘积是量子计算中的基础步骤。本文提出由灵活设计的多量子比特门构成的量子变分指令集（QuVIS），以实现更高速度和精度的量子计算。实现QuVIS门所需的量子比特控制通过细粒度时间优化算法变分地实现。与由标准QIS（如量子微指令集QuMIS，由包括单量子比特旋转和受控非门在内的若干一、二量子比特门构成）编译相比，在实现多量子比特交换和量子傅里叶变换时，QuVIS在误差累积和时间成本上均展现出显著降低。在相同的量子硬件需求下，QuVIS的时间成本降至QuMIS的一半以下。同时，随着编译电路深度的降低，误差呈代数级抑制。作为一种具有高灵活性和效率的通用编译方法，QuVIS可针对不同量子电路进行定义，并适配具有不同相互作用的量子硬件。