论文标题
组合优化的易耐断层量子启发式的汇编
Compilation of Fault-Tolerant Quantum Heuristics for Combinatorial Optimization
论文作者
论文摘要
在这里,我们探讨了使用哪种组合优化的启发式量子算法,可以尝试使用易于故障的小量子计算机。我们为几种量子加速的模拟退火进行了编译,包括使用Qubitization或Szegedy Walk进行量化经典Markov链的电路,以及模拟频谱差距放大的汉密尔顿人编码Gibbs状态的量子。我们还优化了绝热算法,量子增强的人群转移,量子近似优化算法和其他方法的耐断层实现。这些方法中的许多是通过对同一子例程的调用来瓶颈的。因此,无论启发式方面在实践中最有效,都应为这些原语的优化电路引起人们的关注。我们为几个优化问题系列的瓶颈编制了这些瓶颈,并报告了在一系列资源预算的情况下,在表面代码中可以执行这些启发式方法的时间和尺寸系统。我们的结果不鼓励任何量子优化启发式实现只有二次加速的启发式启发式的观念,将在适度的超导量子表面代码处理器上获得优于经典算法,而没有显着改善表面代码的实现。例如,在量子上有利的假设(例如,量子算法上需要少于四个步骤)中,我们的分析表明,量子加速的模拟退火将需要大约一天和一百万个物理速度才能优化可以通过大约四个Cpu-minite s of Offlassical Simical的旋转玻璃来解决的旋转玻璃。
Here we explore which heuristic quantum algorithms for combinatorial optimization might be most practical to try out on a small fault-tolerant quantum computer. We compile circuits for several variants of quantum accelerated simulated annealing including those using qubitization or Szegedy walks to quantize classical Markov chains and those simulating spectral gap amplified Hamiltonians encoding a Gibbs state. We also optimize fault-tolerant realizations of the adiabatic algorithm, quantum enhanced population transfer, the quantum approximate optimization algorithm, and other approaches. Many of these methods are bottlenecked by calls to the same subroutines; thus, optimized circuits for those primitives should be of interest regardless of which heuristic is most effective in practice. We compile these bottlenecks for several families of optimization problems and report for how long and for what size systems one can perform these heuristics in the surface code given a range of resource budgets. Our results discourage the notion that any quantum optimization heuristic realizing only a quadratic speedup will achieve an advantage over classical algorithms on modest superconducting qubit surface code processors without significant improvements in the implementation of the surface code. For instance, under quantum-favorable assumptions (e.g., that the quantum algorithm requires exactly quadratically fewer steps), our analysis suggests that quantum accelerated simulated annealing would require roughly a day and a million physical qubits to optimize spin glasses that could be solved by classical simulated annealing in about four CPU-minutes.