Scientists Just Triggered The Coldest Chemical Reaction in The Known Universe

科学家们刚刚引发了已知宇宙中最冷的化学反应

Set in the middle of a mass of laser equipment, researchers have managed to trigger the coldest chemical reaction in the known Universe. This feat promises to reveal some essential truths about how the building blocks of matter react at ultra-low temperatures.

在一堆激光设备中间，研究人员成功地引发了已知宇宙中最冷的化学反应。这一壮举有望揭示物质在超低温度下如何反应的一些基本事实。

How cold is the reaction exactly? We're talking in the region of 500 nanokelvin - just a few millionths of a degree above absolute zero. The frigid nature of this set-up is important, since at these sort of temperatures molecules tend to slow to the point of almost stopping.

反应到底有多冷?我们说的是500纳克尔文的区域——只比绝对零度高百万分之一度。这种结构的寒冷性质很重要，因为在这种温度下，分子往往会减速到几乎停止的程度。

If you want a chemical reaction to happen, tardy molecules are not what you'd typically be after. But in this case, the reduction in both temperature and speed gave the Harvard University-led team the opportunity to see something that's never been observed before: the moment when two molecules meet together and form... two new molecules.

如果你想要一个化学反应发生，延迟分子不是你通常想要的。但在这种情况下，温度和速度的降低让哈佛大学领导的研究小组有机会看到以前从未观察到的现象:两个分子相遇并形成……两个新的分子。

Probably in the next couple of years, we are the only lab that can do this, says physicist Ming-Guang Hu, from Harvard University.

来自哈佛大学的物理学家胡明光说:“可能在未来几年，我们是唯一能做到这一点的实验室。”

Chemical reactions take just a picosecond, which makes trying to capture what happens in that time frame very tricky indeed. Even ultra-fast lasers acting as cameras can usually capture the start and end of a reaction, not what happens in the middle.

化学反应只需要一皮秒，这使得试图捕捉在那个时间段内发生的事情变得非常棘手。即使是作为摄像机的超高速激光通常也能捕捉到反应的开始和结束，而不是中间发生的事情。

Slowing the reaction in the extremely cold temperatures achieved by the team was therefore the perfect solution.

因此，在极低的温度下减缓反应是一个完美的解决方案。

Because [the molecules] are so cold, now we kind of have a bottleneck effect, says chemical biologist Kang-Kuen Ni, also from Harvard University.

同样来自哈佛大学的化学生物学家倪康坤(Kang-Kuen Ni，音译)说:“因为(这些分子)太冷了，现在我们有了瓶颈效应。”

The absolute coldest temperature in the Universe is absolute zero - but it's impossible to achieve, because it means atoms would stop completely. We can, however, get close to it.

宇宙中最冷的温度是绝对零度——但这是不可能实现的，因为这意味着原子会完全停止运动。然而，我们可以接近它。

Ultra-low temperatures mean ultra-low energy, which in turn means a much slower reaction: two potassium rubidium molecules chosen for their pliability were delayed in the reaction stage for microseconds (millionths of a second).

超低的温度意味着超低的能量，这反过来又意味着反应要慢得多:两个选择的具有柔韧性的铷钾分子在反应阶段被延迟了几微秒(百万分之一秒)。

A technique known as photoionisation detection was then used to observe what was happening to the two molecules, giving scientists invaluable real data to help inform their models and hypotheses.

随后，一种被称为光离子检测的技术被用来观察这两个分子发生了什么，这为科学家提供了宝贵的真实数据，帮助他们建立模型和提出假设。

Being able to observe chemical reactions at such close quarters and at such a fundamental level opens up the possibility of being able to design new reactions too – an almost limitless number of combinations are imaginable, potentially useful in everything from material construction to quantum computing.

能够在如此近的距离和如此基础的水平上观察化学反应，也开启了设计新反应的可能性——人们可以想象到几乎无限数量的组合，从材料结构到量子计算，它们都有潜在的用途。

It's a journey that Kang-Kuen Ni has been on for years – working at incredibly small scales to observe and to control what happens when chemicals react with each other.

这是倪康坤多年来一直在从事的一项研究——在非常小的范围内观察和控制化学物质之间的相互反应。

Now the team is investigating ways in which chemical reactions could be influenced or manipulated to order – either changing the energies involved before the reaction happens, or even nudging the molecules to alter the reaction while it's in progress.

现在，研究小组正在研究如何影响或操纵化学反应以使之有序的方法——或者在反应发生前改变所涉及的能量，或者甚至在反应进行中轻推分子来改变反应。

With our controllability, this time window is long enough, we can probe, says Hu. "Now, with this apparatus, we can think about [influencing reactions]. Without this technique, without this paper, we cannot even think about this."

“由于我们的可控能力，这个时间窗口足够长，我们可以进行探索，”胡说。“现在，有了这个装置，我们可以考虑(影响反应)。没有这项技术，没有这张纸，我们甚至无法思考这个问题。”

The research is published in Science.

这项研究发表在《科学》杂志上。