Knill E
Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Nature. 2005 Mar 3;434(7029):39-44. doi: 10.1038/nature03350.
In theory, quantum computers offer a means of solving problems that would be intractable on conventional computers. Assuming that a quantum computer could be constructed, it would in practice be required to function with noisy devices called 'gates'. These gates cause decoherence of the fragile quantum states that are central to the computer's operation. The goal of so-called 'fault-tolerant quantum computing' is therefore to compute accurately even when the error probability per gate (EPG) is high. Here we report a simple architecture for fault-tolerant quantum computing, providing evidence that accurate quantum computing is possible for EPGs as high as three per cent. Such EPGs have been experimentally demonstrated, but to avoid excessive resource overheads required by the necessary architecture, lower EPGs are needed. Assuming the availability of quantum resources comparable to the digital resources available in today's computers, we show that non-trivial quantum computations at EPGs of as high as one per cent could be implemented.
理论上，量子计算机提供了一种解决传统计算机难以处理的问题的方法。假设能够构建一台量子计算机，实际上它需要在被称为“门”的有噪声设备上运行。这些门会导致对于计算机操作至关重要的脆弱量子态发生退相干。因此，所谓“容错量子计算”的目标就是即使在每个门的错误概率（EPG）很高时也能准确计算。在此，我们报告一种用于容错量子计算的简单架构，证明对于高达百分之三的EPG，准确的量子计算是可行的。这样的EPG已通过实验证明，但为避免必要架构所需的过多资源开销，需要更低的EPG。假设可获得与当今计算机中可用数字资源相当的量子资源，我们表明对于高达百分之一的EPG，也能够实现非平凡的量子计算。
