A BATHING cap that can watch individual neurons, allowing others to monitor the wearer’s mind. A sensor that can spot hidden nuclear submarines. A computer that can discover new drugs, revolutionise securities trading and design new materials. A global network of communication links whose security is underwritten by unbreakable physical laws. Such—and more—is the promise of quantum technology.

可以监测人类神经细胞甚至监控思维的浴帽；可以识别隐身核潜艇的感测器；可以发现新药剂、变革证券交易和设计新材料的计算机；以及在物理定律保护下的全球性通信网络。上述种种——乃至更多——皆是量子技术的应用。

All this potential arises from improvements in scientists’ ability to trap, poke and prod single atoms and wispy particles of light called photons. Today’s computer chips get cheaper and faster as their features get smaller, but quantum mechanics says that at tiny enough scales, particles sail through solids, short-circuiting the chip’s innards. Quantum technologies come at the problem from the other direction. Rather than scale devices down, quantum technologies employ the unusual behaviours of single atoms and particles and scale them up. Like computerisation before it, this unlocks a world of possibilities, with applications in nearly every existing industry—and the potential to spark entirely new ones.

所有这些可能性都是由于科学家提升了捕捉操控单一原子和光子（微小光粒子）的能力。如今，计算机芯片价格越来越便宜，速度却更快，样式也更小巧，但量子力学认为，在体积足够小的情况下，粒子可以穿过固体，使得芯片内部的部件短路。量子技术利用反向思维解决这个问题。与缩小装置相反，量子技术利用单一原子和粒子的异常活动方式，并将其放大。就像在此之前的计算机化一样，这项技术激发了无限可能，几乎可以应用到现存所有产业，并且有可能激发全新的产业。

Strange but true

奇异而真实

Quantum mechanics—a theory of the behaviour at the atomic level put together in the early 20th century—has a well-earned reputation for weirdness. That is because the world as humanity sees it is not, in fact, how the world works. Quantum mechanics replaced wholesale the centuries-old notion of a clockwork, deterministic universe with a reality that deals in probabilities rather than certainties—one where the very act of measurement affects what is measured. Along with that upheaval came a few truly mind-bending implications, such as the fact that particles are fundamentally neither here nor there but, until pinned down, both here and there at the same time: they are in a “superposition” of here-there-ness. The theory also suggested that particles can be spookily linked: do something to one and the change is felt instantaneously by the other, even across vast reaches of space. This “entanglement” confounded even the theory’s originators.

量子力学是20世纪早期一项研究原子行为的学说，以其不可思议而闻名。这是因为它提出，人类眼中的世界并不是真实的世界。量子力学提出宇宙是千变万化而非固定不变的，这否定了几百年来对于宇宙是有规律、不可逆转的认知——其中一则指出正是测量的标准影响了测量对象。这些理论在带来剧变的同时，也提供了一些令人兴奋的消息，例如，从根本上来说，粒子既不在这里也不在那里，但是，当我们控制了它们的时候，又同时存在于各处。换言之，它们处于“这里”和“那里”这两个状态的“叠加态”。这项理论还认为，粒子能够以奇异的方式相互连接：改变其中一个粒子，另一个会即刻感知到变化，即使两个粒子相隔很远。这种“纠缠”即使是理论的创始人都难以理解。

It is exactly these effects that show such promise now: the techniques that were refined in a bid to learn more about the quantum world are now being harnessed to put it to good use. Gizmos that exploit superposition and entanglement can vastly outperform existing ones—and accomplish things once thought to be impossible.

如今，正是这些变化揭示了前景：人们曾经改进这些技术，希望可以更多地了解量子世界；现在，这些技术派上了用场。采用了叠加原理和量子纠缠的小发明很大程度上远超现有发明，同时这些发明还能够完成以往被认为是不可能的任务。

Improving atomic clocks by incorporating entanglement, for example, makes them more accurate than those used today in satellite positioning. That could improve navigational precision by orders of magnitude, which would make self-driving cars safer and more reliable. And because the strength of the local gravitational field affects the flow of time (according to general relativity, another immensely successful but counter-intuitive theory), such clocks would also be able to measure tiny variations in gravity. That could be used to spot underground pipes without having to dig up the road, or track submarines far below the waves.

例如，通过加入量子纠缠技术改进的原子钟，在卫星定位上比现在所用的更精准。这能够以数量级为单位提升导航的精准度，从而使无人车驾驶更安全可靠。并且，因为重力场的力对时间流动产生影响（基于反直觉理论，即广义相对论），这种原子钟也能够测量出细微的重力变化。利用这一点，无需动土就可以定位地下管道，或者追踪深海潜水艇。

Other aspects of quantum theory permit messaging without worries about eavesdroppers. Signals encoded using either superposed or entangled particles cannot be intercepted, duplicated and passed on. That has obvious appeal to companies and governments the world over. China has already launched a satellite that can receive and reroute such signals; a global, unhackable network could eventually follow.

量子理论还可以使人们在通信中无须担心遭窃听。运用叠加原理或量子纠缠技术加密的信号源无法被拦截、复制和传递。显然，这对于全世界的企业和政府来说极具吸引力。中国已经发射了一台能够接收、改道这种信号的卫星；没有黑客攻击的全球网络指日可待。

The advantageous interplay between odd quantum effects reaches its zenith in quantum computers. Rather than the 0s and 1s of standard computing, a quantum computer’s bits are in superpositions of both, and each “qubit” is entangled with every other. Using algorithms that recast problems in quantum-amenable forms, such computers will be able to chomp their way through calculations that would take today’s best supercomputers millennia. Even as high-security quantum networks are being developed, a countervailing worry is that quantum computers will eventually render obsolete today’s cryptographic techniques, which are based on hard mathematical problems.

奇异的量子效应间的相互影响在量子计算机上最能展现其优势。与标准计算机使用0和1不同，量子计算机的比特使用两者的叠加，每个“量子比特”（qubit）都彼此纠缠。如果使用遵循量子格式的算法，那么如今最快的超级计算机要花上一千年才能完成的计算，这种计算机能够迅速完成。安全系数很高的量子网络正在开发，人们担心量子计算机最终将取代现在依据复杂数学问题的编程。

Long before that happens, however, smaller quantum computers will make other contributions in industries from energy and logistics to drug design and finance. Even simple quantum computers should be able to tackle classes of problems that choke conventional machines, such as optimising trading strategies or plucking promising drug candidates from scientific literature. Google said last week that such machines are only five years from commercial exploitability. This week IBM, which already runs a publicly accessible, rudimentary quantum computer, announced expansion plans. As our Technology Quarterly in this issue explains, big tech firms and startups alike are developing software to exploit these devices’ curious abilities. A new ecosystem of middlemen is emerging to match new hardware to industries that might benefit.

然而，这是很久之后的事了，在此之前，小型的量子计算机将为能源、物流、药品设计和金融产业做出贡献。即使是简单的量子计算机也能解决各类困扰传统计算机的问题，例如完善贸易战略，或将科学文献中可做药剂的配方挑选出来。上周，谷歌称，这种机器只需五年就能投入商业使用了。这周，国际商用机器公司（IBM）宣布了扩张计划，它在很早前就已经向公众出售初级量子计算机的。正如本报科技季刊（Technology Quarterly）在这个问题上的报道，大型科技公司和新兴企业正在开发运用软件，探索这些设备不同寻常的能力。新型的过渡系统正在形成，这为可能受利的产业配置新型硬件。

The solace of quantum

量子危机

This landscape has much in common with the state of the internet in the early 1990s: a largely laboratory-based affair that had occupied scientists for decades, but in which industry was starting to see broader potential. Blue-chip firms are buying into it, or developing their own research efforts. Startups are multiplying. Governments are investing “strategically”, having paid for the underlying research for many years—a reminder that there are some goods, such as blue-sky scientific work, that markets cannot be relied upon to provide.

这种情形与上世纪90年代早期因特网的情况十分类似：科学家们花费数十年研究的技术的技术，虽然还处于实验室阶段，但各个产业已经开始看到其他技术的巨大潜力。蓝筹股企业打算买进，或自行研发；新兴企业不断涌现；长年资助这项具有潜力研究的各国政府正在进行“战略”投资——再次表明有些纯理论层面的项目，光靠市场是无力支持的。

Fortunately for quantum technologists, the remaining challenges are mostly engineering ones, rather than scientific. And today’s quantum-enhanced gizmos are just the beginning. What is most exciting about quantum technology is its as yet untapped potential. Experts at the frontier of any transformative technology have a spotty record of foreseeing many of the uses it will find; Thomas Edison thought his phonograph’s strength would lie in elocution lessons. For much of the 20th century “quantum” has, in the popular consciousness, simply signified “weird”. In the 21st, it will come to mean “better”.

幸运的是，量子科学家们剩余的挑战大多是工程技术而非科学上的。并且如今运用量子的小发明才刚起步。量子技术最令人激动的是它仍未开发的潜力。走在技术变革前沿的专家，在预测尚未被发现的发明时，常会出现偏差：爱迪生曾经以为他的留声机会用在朗诵课上。在20世纪绝大多数时间里，“量子”在人们的认知中代表着“怪异”。在21世纪，它会意味着“更好”。

编译：赵若蝉

编辑：钦君

来源 ：经济学人