Quantum computing startup says it will leapfrog everybody
Quantum computing startup says it will leapfrog everybody
量子计算初创公司称将实现跨越式发展
A short time back, we covered an announcement by Amazon that it would be hosting a useful quantum computer from its partner QuEra as soon as sometime in 2028. The system promised some eye-popping numbers compared to anything on the market today: over 10,000 individual qubits, each with an error rate low enough that the system could support hundreds of error-corrected logical qubits. 不久前，我们报道了亚马逊的一项公告，称其将于 2028 年某个时间点托管其合作伙伴 QuEra 开发的一台实用型量子计算机。与目前市场上的任何产品相比，该系统承诺了一些令人瞩目的数据：超过 10,000 个独立量子比特，且每个量子比特的错误率足够低，足以支持数百个经过纠错的逻辑量子比特。
But QuEra has to get there from its current hardware, which sits at 260 qubits that are relatively error-prone. Those details about how it was going to get there were left for last Wednesday, when QuEra announced its roadmap. But the announcement only accentuated the gap: There will be no new hardware releases between now and the useful machine, and QuEra is promising to deliver an even more powerful machine just one year later. 但 QuEra 必须从其现有的硬件起步，目前的硬件仅有 260 个量子比特，且相对容易出错。关于如何实现这一目标的细节留到了上周三，当时 QuEra 公布了其路线图。然而，该公告反而凸显了差距：从现在到那台实用型机器问世之前，不会有新的硬件发布，而且 QuEra 承诺仅在一年后就交付一台更强大的机器。
“The company made a strategic decision not to sell NISQ [noisy intermediate scale quantum] systems anymore,” QuEra’s Yuval Borger told Ars. The two systems it had previously made available have similar capabilities, with about 250 hardware qubits and an appreciable error rate—enough to test some error correction codes, but not sufficient for using logical qubits in applications. “公司做出了一个战略决定，不再销售 NISQ（含噪声中等规模量子）系统，”QuEra 的 Yuval Borger 告诉 Ars。该公司此前提供的两个系统功能相似，拥有约 250 个硬件量子比特和相当高的错误率——足以测试一些纠错码，但不足以在应用中使用逻辑量子比特。
The machine it proposes to build for Amazon will be a very different beast. It will have over 10,000 physical qubits, which QuEra intends to use to create 256 error corrected logical qubits. With error correction active, these will experience 99.9999 percent error-free operations, which the company expects will enable millions of operations to be performed successfully. 它提议为亚马逊建造的机器将完全不同。它将拥有超过 10,000 个物理量子比特，QuEra 打算利用这些量子比特创建 256 个经过纠错的逻辑量子比特。在启用纠错功能的情况下，这些逻辑量子比特将实现 99.9999% 的无错误运行，公司预计这将使数百万次操作能够成功执行。
And there’s a follow on. By 2029, QuEra promises a successor with twice as many hardware qubits, capable of supporting over 1,000 logical qubits. Error resistance will rise to 99.9999999 percent. 此外还有后续计划。到 2029 年，QuEra 承诺推出一款继任机型，其硬件量子比特数量将翻倍，能够支持超过 1,000 个逻辑量子比特。错误抵御能力将提升至 99.9999999%。
QuEra’s machines operate using neutral atoms that are held in a grid by lasers, so raising the qubit count is largely a matter of boosting the laser capacity. And the two academic labs that launched QuEra and licensed IP to it have already demonstrated a 3,000-qubit system. Scaling that will be a challenge, but there’s an obvious route to it. The labs have also demonstrated the ability to replace atoms lost during operations, an ability that’s critical to keeping these machines running. QuEra 的机器使用中性原子运行，这些原子通过激光固定在网格中，因此提高量子比特数量很大程度上取决于提升激光容量。而创办 QuEra 并向其授权知识产权的两家学术实验室已经演示了一个 3,000 量子比特的系统。扩展该系统将是一个挑战，但已有明确的路径。这些实验室还展示了替换运行中丢失原子的能力，这对于维持机器运行至关重要。
The bigger challenge QuEra faces will be that these future machines require getting the error rates of the hardware qubits down dramatically. As a rough approximation, the error rates of logical qubits depend on a combination of how many hardware qubits are used to create the logical ones, and the error rate of the hardware qubits. If you get the hardware error rate down, you can get similar error correction performance out of a logical qubit built with fewer hardware ones. QuEra 面临的更大挑战是，这些未来的机器需要大幅降低硬件量子比特的错误率。粗略估计，逻辑量子比特的错误率取决于用于创建逻辑量子比特的硬件量子比特数量，以及硬件量子比特本身的错误率。如果能降低硬件错误率，就可以用更少的硬件量子比特构建出具有相同纠错性能的逻辑量子比特。
In its 2028 machine, QuEra will be using an error correction code that requires 40 hardware qubits for each logical qubit. One year later, it intends to cut the hardware qubits per logical qubit to 20. Cutting it to that number will require the hardware error rate to go down just to keep the same level of performance, except QuEra is also promising dramatically better performance, which means the hardware error rate will drop even further. It’s unclear where that sort of drop is going to come from, especially given it’s only expected to take one year. 在其 2028 年的机器中，QuEra 将使用一种纠错码，每个逻辑量子比特需要 40 个硬件量子比特。一年后，它打算将每个逻辑量子比特所需的硬件量子比特数减少到 20 个。要达到这个数字，不仅需要降低硬件错误率以维持相同的性能水平，而且 QuEra 还承诺提供大幅提升的性能，这意味着硬件错误率必须进一步下降。目前尚不清楚这种下降将如何实现，尤其是考虑到这预计仅需一年时间。
When we asked QuEra about the biggest challenges remaining, the error rate wasn’t mentioned specifically. “A lot of the challenges between now and a production system on the cloud are classical challenges, not quantum challenges: control electronics, real-time quantum error correction, building compilers that allow users to easily tap into the power of the system,” Borger told Ars. 当我们询问 QuEra 目前面临的最大挑战时，并未特别提到错误率。“从现在到云端生产系统之间，许多挑战都是经典挑战，而非量子挑战：控制电子设备、实时量子纠错、构建让用户能够轻松利用系统算力的编译器，”Borger 告诉 Ars。
Although the company has listed the current error rates for its hardware (which are very good, but not presently good enough for this), it is not specifying the level of performance that will be needed to achieve its planned goals. The announcement is potentially exciting, but it’s difficult to evaluate how seriously to take QuEra’s plans. 尽管该公司列出了其硬件当前的错误率（表现非常好，但目前还不足以实现这一目标），但并未明确指出实现其计划目标所需的性能水平。这一公告可能令人兴奋，但很难评估 QuEra 的计划究竟有多大的可信度。