比特和量子比特 (Bits and qubits)

Quantum mechanics is weird. In the realm of the very, very small, things are not as our intuition tells us they should be.

量子力学很奇怪。 在非常非常小的范围内，事情不是我们的直觉告诉我们应该做的。

Particles can be in multiple states at the same time (superposition) and multiple particles can react to each other’s states instantaneously, no matter how far away from each other they are (entanglement, aka spooky action at a distance).

粒子可以同时处于多个状态(叠加)，并且多个粒子可以立即对彼此的状态做出React，而无论它们彼此之间有多远(纠缠，也就是距离有怪异的作用 )。

While these phenomena make a mockery of our common sense conception of reality, they could be very useful in certain fields of computing. Hence, the field of quantum computing, which seeks to exploit quantum weirdness to expand the scope and complexity of the problems computers can tackle.

尽管这些现象嘲笑了我们对常识的现实概念，但它们在某些计算领域可能非常有用。 因此， 量子计算领域寻求利用量子怪异来扩展计算机可以解决的问题的范围和复杂性。

Especially superposition is explored as foundation for quantum computers.

特别是叠加被探索为量子计算机的基础。

Normal bits are 1 or 0.

普通位是1或0。

But quantum bits, or qubits, can be 1 or 0 or a mixture of both. Pretty handy. (Although they do ‘collapse’ into a 1 or 0 when measured.)

但是量子位或量子位可以是1或0或两者的混合。 很方便。 (尽管在测量时它们确实会“折叠”为1或0。)

These qubits can also be entangled, meaning that measuring one would automatically give you information about the other, even without measuring it.

这些量子位也可以纠缠在一起，这意味着测量一个将自动为您提供有关另一个的信息，即使不进行测量也是如此。

破解代码 (Breaking code)

Quantum computing appears to be exceptionally promising in the field of cryptography, both in terms of creating new, harder to break codes, and breaking codes that regular computers have problems with. (A little less than a year ago, Google AI and NASA claimed to have performed a quantum computation that is unfeasible on a classical computer.)

在创建新的，更难以破解的代码以及破解常规计算机遇到的代码方面，量子计算在密码学领域似乎都非常有前途。 (不到一年前， Google AI和NASA声称执行了量子计算，这在传统计算机上是不可行的 。)

For example, copying quantum data is hard, because looking at it (=measurement) makes it ‘collapse’. Vice versa, some current cryptographic systems use things such as prime factorization (where a very large number is decomposed into a number of smaller primes). Finding these prime numbers is very computationally intensive. If, however, you have a quantum system that can contain many different states at the same time, it suddenly becomes easier (Shor’s algorithm is an illustration of this).

例如，复制量子数据很困难，因为看着它(=测量值)会使它“崩溃”。 反之亦然，一些当前的密码系统使用诸如素数分解(将大量分解为许多较小的素数)之类的东西。 查找这些素数在计算上非常费力。 但是，如果您拥有一个可以同时包含许多不同状态的量子系统，则它突然变得容易起来( Shor的算法就是对此的说明)。

If this makes your head hurt, that’s good, that’s what it’s supposed to do.

如果这使您的头部受伤，那就很好了，那就应该这样做。

一步一步来 (One step at a time)

Despite all their promise, quantum computers have a great weakness: they’re very fragile.

尽管有它们的全部诺言，量子计算机还是有一个很大的弱点：它们非常脆弱。

As mentioned above, a ‘measurement’ makes the superposition state collapse. In this context, though, measurement should be interpreted very broadly. Looking at something is a measurement. Shining light on something is a measurement. Heat — aka bumping molecules into each other — is a measurement. In quantum terms, a measurement is almost equivalent to any interaction with the external world. Nudge a quantum system and it collapses into a specific state, destroying the superposition (‘decoherence’).

如上所述，“测量”会使叠加状态崩溃。 但是，在这种情况下，应该对测量进行非常广泛的解释。 看东西是一种测量。 照亮某物是一种度量。 热量(又称分子相互碰撞)是一种度量。 用量子术语来说，测量几乎等同于与外界的任何相互作用。 轻推一个量子系统，它崩溃成一个特定的状态，破坏了叠加(“退相干”)。

That’s why current quantum computers are still very small (a limited number of qubits), kept very cold, and very well shielded. A few months ago, the company Honeywell unveiled the largest quantum computer to date: 64 qubits. No gigabytes here.

这就是为什么目前的量子计算机仍然非常小(数量有限的量子位)，保持非常冷并且被很好地屏蔽的原因。 几个月前， 霍尼韦尔公司推出了迄今为止最大的量子计算机 ：64量子位。 这里没有千兆字节。

We’re still making headway, though. Slowly but persistently.

不过，我们仍在取得进展。 缓慢但持续。

宇宙密谋反对我们 (The universe conspires against us)

Maybe, though, the universe itself will get in the way. Every moment of every day, we are being bombarded by a barrage of particles. Not just from possible radiation sources nearby, but also from the radiation that is a remnant from the big bang and far away cosmic events: cosmic background radiation.

不过，也许宇宙本身会妨碍您。 每天的每一刻，我们都被一连串的粒子轰炸。 不仅来自附近可能的辐射源，还来自大爆炸和遥远的宇宙事件遗留下来的辐射 ： 宇宙背景辐射 。

As quantum computers get larger and larger, the odds of being struck by a stray cosmic particle increase. A new study argues that environmental and cosmic radiation would strongly limit the coherence time of large quantum systems:

随着量子计算机变得越来越大，被流浪宇宙粒子撞击的几率增加。 一项新的研究认为，环境和宇宙辐射将极大地限制大型量子系统的相干时间：

The effect of ionizing radiation leads to an elevated quasiparticle density, which we predict would ultimately limit the coherence times of superconducting qubits of the type measured here to milliseconds.

电离辐射的影响导致准粒子密度升高，我们预测这最终将把此处测量的超导量子位的相干时间限制为毫秒。

But not all is lost:

但并非所有都丢失了：

…developing techniques — such as lead shielding, quasiparticle trapping, and designing devices with reduced quasiparticle sensitivity — to mitigate its impact on superconducting circuits, including those used for quantum computation.

…开发技术(例如铅屏蔽，准粒子捕获和设计具有降低准粒子灵敏度的设备)以减轻其对超导电路(包括那些用于量子计算的电路)的影响。

In other words, it is challenging but possible to shield quantum computers for cosmic and nearby radiation sources. Massive lead shields, underground facilities, and other techniques will still allow us to progress. It’s not going to be easy or cheap, though.

换句话说，这是具有挑战性的，但有可能为量子计算机屏蔽宇宙和附近的辐射源。 大规模的铅盾，地下设施和其他技术仍将使我们取得进步。 但是，它不会容易或便宜。

Don’t look now, or it’ll collapse.

现在不要看，否则它会崩溃。

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For more science/writing madness, Twitter (@evolveon) is the place to be. Come say hi.

对于更多的科学/写作狂热，可以使用Twitter(@evolveon)。 快打个招呼吧