Sooner than expected? Useful quantum error correction promised for 2028.
Sooner than expected? Useful quantum error correction promised for 2028.
比预期更快？2028年有望实现实用的量子纠错
Quantum computing news usually picks up near the end of the year, as companies try to provide evidence that they are hitting benchmarks on time. However, there have been interesting announcements as the summer starts this year, from incremental progress to attention-grabbing promises. As we did earlier this month, Ars has a rundown of some of the most significant announcements. These include a promise of useful, error-corrected quantum computing as soon as 2028, details on an updated trapped ion processor, and a case in which claims of quantum supremacy have been cut back a bit thanks to advances in more traditional algorithms.
量子计算领域的新闻通常在年底趋于活跃，因为各家公司都试图证明他们按时完成了既定目标。然而，今年夏季伊始，该领域就出现了一些有趣的公告，从渐进式的技术突破到引人注目的承诺，不一而足。正如我们本月初所做的那样，Ars 对一些最重要的公告进行了梳理。其中包括承诺最早在 2028 年实现实用的量子纠错计算、关于升级版离子阱处理器的详细信息，以及由于传统算法的进步，量子霸权主张被适度削弱的案例。
2028 is remarkably soon
2028 年指日可待
Many people in the field expect that useful quantum computers are still about five to 10 years away. While there may be a few useful algorithms that can be run on existing error-prone hardware, almost all of the interesting problems that quantum computing can be applied to will require some form of error correction enabled by linking a small collection of hardware qubits together into what’s called a logical qubit. Logical qubits include the redundant storage of information along with neighboring qubits that can be measured to determine when errors occur and how to fix them.
该领域的许多专家认为，实用的量子计算机距离我们还有大约 5 到 10 年的时间。虽然现有的易错硬件上可以运行一些有用的算法，但量子计算所能解决的几乎所有核心问题，都需要某种形式的纠错机制——即将一小部分硬件量子比特连接在一起，形成所谓的“逻辑量子比特”。逻辑量子比特包含信息的冗余存储，并辅以相邻的量子比特，通过测量这些相邻比特，可以确定错误发生的时间并进行修复。
To do useful computations, you need a healthy number of logical qubits—roughly 100 to provide a complete model of the behavior of some simple chemicals, to tens of thousands to perform complicated algorithms like the one that can break encryption. (So, any definition of “useful” comes with the important caveat “for whom?”) That means, at a minimum, we’re going to need thousands of high-quality hardware qubits to build a useful error-corrected machine. At the moment, existing qubit technologies offer either high quality or lots of qubits. There are roadmaps from here to where we want to be, but they require a few years of incremental progress. Hence, the five- to 10-year estimates.
要进行有用的计算，需要足够数量的逻辑量子比特——大约需要 100 个来完整模拟某些简单化学物质的行为，而要执行像破解加密算法这样复杂的任务，则需要数万个。（因此，对“有用”的任何定义都伴随着一个重要的前提：“对谁有用？”）这意味着，至少我们需要数千个高质量的硬件量子比特才能构建出一台实用的纠错机器。目前，现有的量子比特技术要么提供高质量，要么提供大量比特。虽然从现状到目标已有路线图，但仍需要几年的渐进式发展。因此，普遍的估计是 5 到 10 年。
On Monday, Amazon and QuEra claimed they will get there in two years. “By 2028, we will bring Libra, a Megaquop-scale device, capable of executing one million quantum operations over hundreds of logical qubits, to our customers, enabling first scientific applications in quantum chemistry, high-energy physics, and materials simulation that are beyond the reach of classical and Noisy Intermediate-Scale Quantum (NISQ) computers today,” Amazon’s statement said.
周一，亚马逊和 QuEra 声称他们将在两年内实现这一目标。亚马逊在声明中表示：“到 2028 年，我们将向客户提供 Libra，这是一款‘兆级量子操作’（Megaquop-scale）设备，能够在数百个逻辑量子比特上执行一百万次量子操作，从而在量子化学、高能物理和材料模拟领域实现首批科学应用，这些应用是当今经典计算机和含噪声中等规模量子（NISQ）计算机所无法企及的。”
Those customers currently have access to a number of different quantum computing technologies via its Braket cloud service. Libra is hardware that will be provided by QuEra, a startup based in the Boston area that is pursuing neutral atom quantum computing by sharing staff and a long-term intellectual property agreement with research groups at Harvard University and the Massachusetts Institute of Technology.
这些客户目前可以通过亚马逊的 Braket 云服务访问多种不同的量子计算技术。Libra 的硬件将由 QuEra 提供，这是一家位于波士顿地区的初创公司，致力于中性原子量子计算。该公司通过与哈佛大学和麻省理工学院的研究小组共享人员并签署长期知识产权协议来开展研发。
Neutral atom quantum computing is based on our ability to use lasers to cool individual atoms and trap them in a grid of overlapping light beams, with the qubit being stored in the spin of the nucleus. Separate laser systems can also move atoms around, providing any-to-any connectivity, which enables considerable flexibility for algorithmic and error-correction purposes. The technology currently falls into the “easy to make lots of them” category of hardware qubits—QuEra’s academic partners have demonstrated a 3,000 qubit grid. However, the operation of these systems tends to heat the atoms, and moving them around is slow, so they get lost at a problematic frequency.
中性原子量子计算基于利用激光冷却单个原子并将其捕获在重叠光束网格中的能力，量子比特存储在原子核的自旋中。独立的激光系统还可以移动原子，提供“任意对任意”的连接性，这为算法和纠错提供了极大的灵活性。该技术目前属于硬件量子比特中“易于大规模制造”的类别——QuEra 的学术合作伙伴已经演示了一个 3,000 量子比特的网格。然而，这些系统的运行往往会加热原子，且移动原子的速度较慢，导致原子丢失的频率较高，这是一个亟待解决的问题。
While the people behind QuEra have demonstrated some impressive error correction, there was still considerable work to do. Understanding how the company plans to get from its current demonstrations to a high-quality system will be essential for evaluating how likely we are to start seeing error-corrected computation before the decade wraps up. This makes the timing of Amazon’s announcement very frustrating, because QuEra intends to lay out a detailed roadmap to its Libra system next week. We’ve been promised a full briefing ahead of that, but for now, all we can say is that the two companies involved aren’t prone to hype, and probably wouldn’t be announcing this if they didn’t have very good reasons to expect things to work out.
尽管 QuEra 背后的团队已经展示了一些令人印象深刻的纠错成果，但仍有大量工作要做。了解该公司如何从目前的演示阶段过渡到高质量系统，对于评估我们在本十年结束前看到纠错计算的可能性至关重要。这使得亚马逊宣布这一消息的时机显得有些令人焦急，因为 QuEra 计划在下周公布其 Libra 系统的详细路线图。我们已被承诺在此之前获得全面简报，但目前我们只能说，这两家公司并不倾向于炒作，如果不是有充分的理由预期事情会成功，他们可能不会宣布这一消息。
A formal description of Helios
Helios 的正式描述
In November, Quantinuum announced its next quantum computing hardware, named Helios, based on trapped ion technology. Trapped ions have some things in common with neutral atoms, but instead of a laser grid, they rely on electronics to move around ionized versions of the atoms. Despite the similarities, the ions are on the opposite sides of the current divide: Existing hardware doesn’t hold many qubits, but the qubits are extremely high-quality.
去年 11 月，Quantinuum 发布了其下一代量子计算硬件 Helios，该硬件基于离子阱技术。离子阱与中性原子有一些共同点，但它不依赖激光网格，而是依靠电子设备来移动离子的原子版本。尽管有相似之处，但离子技术处于当前技术鸿沟的另一端：现有的硬件虽然容纳的量子比特不多，但这些量子比特的质量极高。
In Wednesday’s issue of Nature, the company provides a more detailed technical description of Helios. Nothing has changed from our description of the hardware; it’s still a storage ring linked to two legs where operations take place, with ions flowing into and out of the legs as an algorithm is performed. (Read the link in the paragraph above if you want to know more—it’s a pretty cool system.) But the paper offers some additional details. One of those details involves cooling the ions so they don’t escape the device. The Helios system allows the cooling to be run in parallel to the sorting of ions and other operations. “This parallel sorting with ground-state cooling allows cooling and gating cycles to run nearly continuously, as the next batch of qubits is ready to shift in as the current batch finishes operations,” the paper states. The company also implies that it sees an opportunity to increase the cooling elsewhere in the future to an extent that nearly every ion will be cooled off by the time it’s actually needed for an operation. Helios also comes with a software stack that abstracts its user’s intentions from the actual qubit hardware.
在周三出版的《自然》杂志上，该公司提供了关于 Helios 更详细的技术描述。硬件描述与我们之前的报道并无二致；它仍然是一个连接着两个操作支路的存储环，当算法执行时，离子会流入和流出这些支路。（如果您想了解更多信息，请阅读上文中的链接——这是一个非常酷的系统。）但该论文提供了一些额外的细节。其中一个细节涉及冷却离子以防止它们逃逸出设备。Helios 系统允许在离子排序和其他操作的同时进行并行冷却。论文指出：“这种带有基态冷却的并行排序，使得冷却和门控周期几乎可以连续运行，因为当当前批次的量子比特完成操作时，下一批量子比特已经准备好进入。”该公司还暗示，未来有机会在其他地方进一步加强冷却，以至于几乎每个离子在实际需要进行操作时都能被冷却到位。Helios 还配备了一个软件栈，将用户的意图与实际的量子比特硬件进行了抽象隔离。