Name: 量子鑽石將如何幫助我們探測宇宙碰撞？ (How Quantum Diamonds Will Help Us Detect Cosmic Collisions)
Uploaded: 2020-10-08T19:27:41.000Z
Duration: 4 min 29 s

關係子句

Back in 2015, the two detectors that make up the experiment called LIGO made waves.

早在2015年，這兩臺組成實驗的探測器，名為LIGO的實驗就掀起了波瀾。

Well, technically they detected waves — they picked up the gravitational waves

技術上來說，他們探測到了波，他們接收到了引力波。

It was no small feat, but LIGO is no small experiment;

in order to suss out the signal, the observatories had to use laser beams several kilometers long.

為了弄清信號，觀測站不得不使用幾公里長的激光束。

Now, some researchers believe they can build instruments that can detect gravitational waves even LIGO can't see —

現在，一些研究人員相信他們可以製造出連LIGO都看不到的引力波的儀器------。

instruments that would be small enough to fit on a table top.

To understand what makes this such an impressive claim, first you have to know what an interferometer is.

要想了解是什麼讓這一說法如此令人印象深刻，首先你得知道什麼是干涉儀。

Interferometers like those used by LIGO, which is short for Laser Interferometer Gravitational-Wave Observatory,

像LIGO使用的干涉儀，是脈衝光干涉儀引力波觀測站的簡稱。

take advantage of how beams of light interact with each other to take measurements.

利用光束之間的相互作用來進行測量。

Light behaves like a wave with peaks and troughs,

光的行為就像波浪一樣，有峰有谷。

and when two waves of light interact, their waves will combine either constructively or destructively.

而當兩股光波相互作用時，它們的波會以建設性或破壞性的方式結合起來。

For example, when the peaks of two different waves sync up, they'll produce a taller peak.

例如，當兩個不同的波峰同步時，它們會產生一個較高的波峰。

But when a peak and a trough come together, they'll cancel each other out.

但當一個高峰和一個谷底一起出現時，它們會互相抵消。

These combinations produce an interference pattern that can be measured and analyzed.

這些組合會產生一個可以測量和分析的干擾圖案。

LIGO's two detectors each use a laser with a  beam that's split and sent down perpendicular paths each 4 kilometers long.

LIGO的兩個探測器分別使用脈衝光，光束被分割開來，沿著每條4公里長的垂直路徑發送。

At the end of the path is a mirror, which bounces the beam back towards the beam splitter.

在路徑的末端是一面鏡子，它將光束反彈回分光器。

For some interferometers' purposes that would be more than enough distance, but each of LIGO's arms actually has a second mirror by the beam splitter,

對於一些干涉儀的目的來說，這將是足夠多的距離，但LIGO的每個手臂實際上有一個由分光器的第二個鏡子。

which bounces the laser back over and over again,

將脈衝光一次又一次地反彈回來。

making each beam of light travel 1,200 kilometers before they're allowed to recombine and produce an interference pattern.

使得每束光都要經過1200公里的路程，才允許它們重新組合，併產生一個干擾圖案。

Any tiny vibration that moves the mirrors affects the interference pattern,

任何移動鏡子的微小振動都會影響干擾圖案。

and LIGO can pick up vibrations 10,000 times smaller than a proton,

和LIGO可以接收到比質子小一萬倍的振動。

making its interferometers the most sensitive in the world.

使其干涉儀成為世界上最靈敏的干涉儀。

But even LIGO's incredible sensitivity still isn't enough to detect relatively low-frequency gravitational waves.

但即使是LIGO驚人的靈敏度，仍然不足以探測到相對低頻的引力波。

To detect those with lasers, we would have to build interferometers in space with baselines that are hundreds of thousands of kilometers long.

要想用脈衝光探測這些，我們就必須在太空中建造基線長達數十萬公里的干涉儀。

So, some scientists at the University College London decided to explore another method of making interferometers.

於是，倫敦大學學院的一些科學家決定探索另一種製造干涉儀的方法。

One that involves quantum mechanics and diamonds.

The proposed device would use nanoscale diamonds with defects, called nitrogen-vacancy centers or N-V centers.

擬議的設備將使用具有缺陷的納米級鑽石，稱為氮空中心或N-V中心。

In an N-V center, a nitrogen atom takes the place of a carbon atom and an empty spot in the diamond lattice is left open next to it.

在N-V中心中，一個氮原子取代了一個碳原子的位置，金剛石晶格中的一個空位就在它旁邊空著。

This defect can be treated like two unpaired electrons and its spin can be manipulated.

這種缺陷可以像兩個未配對的電子一樣處理，其自旋可以被操縱。

In fact, these crystals are already used in one approach to quantum computers.

事實上，這些晶體已經被用於量子計算機的一種方法。

The researchers propose a device that would trap the crystals and use microwaves to put their spins in superposition,

研究人員提出了一種裝置，可以捕獲晶體，並使用微波將它們的自旋疊加。

meaning the same N-V center exists simultaneously in two states.

意味著同一個N-V中心同時存在於兩種狀態。

Weird, I know — but that's the quantum realm for you.

我知道很奇怪--但那是你的量子領域。

Anyway, when a magnetic field is applied to the crystals, the two spin states should separate and travel along different paths before meeting up again.

總之，當磁場施加到晶體上時，兩個自旋狀態應該分開並沿著不同的路徑行駛，然後再相遇。

Like LIGO's split laser beams, tiny changes in space should create a  pattern that can be measured and analyzed.

就像LIGO的分裂激光束一樣，空間的微小變化應該會產生一個可以測量和分析的模式。

The researchers believe a device like this that's as small as 1 meter long could reveal low frequency gravitational waves,

研究人員認為，這樣一個小到1米長的裝置可以揭示低頻引力波。

and even help us study the quantum character of gravity.

甚至幫助我們研究引力的量子特性。

Of course, there's one enormous catch: the technology to build an interferometer like this doesn't exist yet.

當然，有一個巨大的問題：製造這樣的干涉儀的技術還不存在。

The scientists are confident that it can be realized in the near future, but until the necessary breakthroughs arrive,

科學家們有信心在不久的將來能夠實現，但在必要的突破性進展到來之前。

I'll just pin my hopes on the next big laser interferometer —

我就把希望寄託在下一個大的脈衝光干涉儀上----------。

ESA and NASA's space-based LISA, a laser interferometer made up of three different spacecraft which is set to launch sometime in the early 2030s.

歐空局和美國航天局的天基LISA，是由三個不同的航天器組成的脈衝光干涉儀，它將在2030年代初的某個時候發射。

Either way, I can't wait for what comes next.

不管是哪種方式，我都迫不及待地想知道接下來的內容。

LIGO's detectors are so sensitive they can pick up vibrations in the Earth from sources thousands of miles away.

LIGO的探測器非常靈敏，可以接收到來自數千英里之外的地球振動。

That's why it uses two detectors, one in Louisiana and one in Washington State,

這就是為什麼它使用兩個探測器，一個在路易斯安那州，一個在華盛頓州。

each acting as a noise filter for the other.

每一個都是另一個的噪聲過濾器。

Since its groundbreaking 2015 discovery, LIGO has been finding more gravitational waves.

自2015年突破性發現以來，LIGO一直在發現更多的引力波。

Earlier in 2020, it detected a neutron star collision. Maren has more on that here.

2020年早些時候，它探測到了一次中子星碰撞。馬倫在這裡有更多的資訊。

Which approach do you prefer: lasers or quantum mechanics?

你喜歡哪種方法：脈衝光還是量子力學？

Let us know in the comments, don't forget to subscribe, and I'll see you next time on Seeker.

請在評論中告訴我們，別忘了訂閱，我們下期《求是》見。