量子電腦解析 —— 人類技術的極限：英語精讀講義

For most of our history, 片語搭配

在人類歷史的大部分時間裡，

human technology consisted of our brains,

人類的科技僅由我們的大腦、

fire, and sharp sticks.

火，以及削尖的木棍所組成。

While fire and sharp sticks became power plants and nuclear weapons, 文法

雖然火和尖木棍後來演變成了發電廠和核子武器，

the biggest upgrade has happened to our brains.

但最大的升級其實發生在我們的大腦上。

Since the 1960s,

自20世紀60年代起，

the power of our brain machines has kept growing exponentially,

我們「大腦機器」的能力持續呈指數級成長，

allowing computers to get smaller and more powerful at the same time.

讓電腦在變得越來越小的同時，也變得越來越強大。

But this process is about to meet its physical limits. 講解

但這個過程即將面臨其物理極限。

Computer parts are approaching the size of an atom.

電腦零件的尺寸正逼近原子的大小。

To understand why this is a problem,

為了解釋為什麼這是個問題，

we have to clear up some basics. 片語動詞

我們必須先釐清一些基礎知識。

A computer is made up of very simple components 片語動詞

電腦是由非常簡單的元件所構成，

doing very simple things,

做著非常簡單的事情：

representing data,

表示資料、

the means of processing it,

處理資料的方法，

and control mechanisms.

以及控制機制。

Computer chips contain modules,

電腦晶片包含模組，

which contain logic gates, 文法

模組包含邏輯閘，

which contain transistors.

邏輯閘包含電晶體。

A transistor is the simplest form of a data processor in computers,

電晶體是電腦中最簡單的資料處理器形式，

basically a switch that can either block or open the way for information coming through.

基本上就是個開關，可以阻擋或允許資訊通過。

This information is made up of bits,

這些資訊由位元所組成，

which can be set to either zero or one.

位元可以被設定為0或1。

Combinations of several bits are used to represent more complex information.

幾個位元的組合被用來表示更複雜的資訊。

Transistors are combined to create logic gates,

電晶體組合起來能建立邏輯閘，

which still do very simple stuff.

而邏輯閘做的事情依然非常簡單。

For example,

舉例來說，

an AND gate sends an output of one if all of its inputs are one, 文法

一個及閘（AND gate）如果所有輸入皆為1，它就會輸出1，

and an output of zero otherwise.

否則輸出0。

Combinations of logic gates finally form meaningful modules,

邏輯閘的組合最終形成了有意義的模組，

say for adding two numbers. 用詞

例如用於兩個數字的加法。

Once you can add, 文法

一旦你能做加法，

you can also multiply,

你就能做乘法，

and once you can multiply,

一旦你能做乘法，

you can basically do anything.

你基本上就能做任何事情了。

Since all basic operations are literally simpler than first grade math,

既然所有的基本運算都比一年級的數學還簡單，

you can imagine a computer as a group of 7-year-olds answering really basic math questions.

你可以把電腦想像成一群7歲小孩在回答非常基礎的數學問題。

A large enough bunch of them could compute anything from astrophysics to Zelda. 表達脈絡

只要人數夠多，從天體物理學到《薩爾達》都能算出來。

However,

然而，

with parts getting tinier and tinier, 文法

隨著零件變得越來越小，

quantum physics are making things tricky.

量子物理學讓事情變得棘手起來。

In a nutshell, 慣用語

簡而言之，

a transistor is just an electric switch.

電晶體只是一個電氣開關。

Electricity is electrons moving from one place to another,

電是電子從一個地方移動到另一個地方，

so a switch is a passage that can block electrons from moving in one direction. 文法

所以開關就是一條可以阻斷電子朝特定方向移動的通道。

Today,

如今，

a typical scale for transistors is 14 nanometers,

電晶體的典型尺度是14奈米，

which is about eight times less than the HIV virus's diameter, 文法

大約是愛滋病毒直徑的八分之一，

and 500 times smaller than a red blood cell.

比紅血球小500倍。

As transistors are shrinking to the size of only a few atoms,

隨著電晶體縮小到只有幾個原子的大小，

electrons may just transfer themselves to the other side of a blocked passage

電子可能會自行穿越被阻斷的通道，抵達另一側，

via a process called quantum tunneling. 講解

這個過程稱為量子穿隧。

In the quantum realm,

在量子領域裡，

physics works quite differently from the predictable ways we're used to, 文法

物理學的運作方式與我們習慣的可預測方式截然不同，

and traditional computers just stop making sense. 片語搭配

傳統的電腦也就變得不再合理了。

We are approaching a real physical barrier for our technological progress.

我們的科技進步正在逼近一個真正的物理障礙。

To solve this problem,

為了解決這個問題，

scientists are trying to use these unusual quantum properties to their advantage 片語搭配

科學家們試圖利用這些不尋常的量子特性，

by building quantum computers.

透過建造量子電腦來將其轉化為優勢。

In normal computers,

在一般電腦中，

bits are the smallest units of information. 文化背景

位元是資訊的最小單位。

Quantum computers use qubits,

量子電腦則使用量子位元（qubit），

which can also be set to one of two values.

它同樣能被設定為兩個值之一。

A qubit can be any two-level quantum system,

一個量子位元可以是任何雙態量子系統，

such as a spin in a magnetic field,

例如磁場中的自旋，

or a single photon.

或是一個單一光子。

Zero and one are this system's possible states,

0和1是這個系統的可能狀態，

like the photon's horizontal or vertical polarization.

就像光子的水平或垂直極化一樣。

In the quantum world,

在量子世界裡，

the qubit doesn't have to be in just one of those, 文法

量子位元不需要僅處於其中一種狀態，

it can be in any proportions of both states at once.

它可以同時處於兩種狀態的任意比例之中。

This is called superposition. 文化背景

這被稱為疊加態。

But as soon as you test its value, 文法

但只要你一測試它的值，

say by sending the photon through a filter,

例如讓光子通過一個濾光片，

it has to decide to be either vertically or horizontally polarized.

它就必須決定是垂直極化還是水平極化。

So, as long as it's unobserved, 文法

因此，只要它未被觀測，

the qubit is in a superposition of probabilities for zero and one,

量子位元就處於0和1機率的疊加態中，

and you can't predict which it will be. 文法

你無法預測它會是哪一個。

But the instant you measure it, 文法

但在你測量它的瞬間，

it collapses into one of the definite states. 用詞

它就會坍縮成一個明確的狀態。

Superposition is a game-changer. 慣用語

疊加態是個能改變遊戲規則的特性。

Four classical bits can be in one of two to the power of four different configurations at a time. 用詞

四個古典位元在同一時間只能處於2的4次方種不同組合中的一種。

That's 16 possible combinations,

也就是16種可能的組合，

out of which you can use just one.

你只能使用其中的一種。

Four qubits in superposition, however,

然而，四個處於疊加態的量子位元，

can be in all of those 16 combinations at once.

可以同時處於這16種組合之中。

This number grows exponentially with each extra qubit. 片語搭配

這個數字隨著每增加一個量子位元呈指數級成長。

20 of them can already store a million values in parallel. 用詞

20個量子位元就已經可以平行儲存一百萬個值。

A really weird and unintuitive property qubits can have is entanglement, 文化背景

量子位元能夠擁有的一個非常奇特且違反直覺的特性是糾纏態，

a close connection that makes each of the qubits react to a change in the other's state instantaneously,

這是一種密切的連結，使得每個量子位元都能對另一個狀態的改變瞬間作出反應，

no matter how far they are apart. 文法

無論它們相隔多遠。

This means that when measuring just one entangled qubit, 文法

這意味著當僅僅測量一個被糾纏的量子位元時，

you can directly deduce properties of its partners without having to look. 文法

你就可以直接推斷出其伴侶的屬性，而無需去查看。

Qubit manipulation is a mind-bender as well. 慣用語

量子位元的操作同樣非常燒腦。

A normal logic gate gets a simple set of inputs

一個普通的邏輯閘接收一組簡單的輸入，

and produces one definite output.

並產生一個確定的輸出。

A quantum gate manipulates an input of superpositions,

而量子閘操作的是疊加態的輸入，

rotates probabilities,

它旋轉機率，

and produces another superposition as its output.

並產生另一個疊加態作為其輸出。

So, a quantum computer sets up some qubits, 片語動詞

所以，量子電腦設定了一些量子位元，

applies quantum gates to entangle them and manipulate probabilities,

應用量子閘使它們糾纏並操作機率，

and finally measures the outcome,

最後測量結果，

collapsing superpositions to an actual sequence of zeros and ones.

將疊加態坍縮為0和1的實際序列。

What this means is that you get the entire lot of calculations 表達脈絡

這意味著，你可以得到的全部可能計算

that are possible with your setup all done at the same time.

都在同一時間全部完成。

Ultimately, you can only measure one of the results,

最終，你只能測量其中一個結果，

and it will only probably be the one you want,

而且它可能只是你想要的那一個結果，

so you may have to double-check and try again.

所以你可能需要反覆核對再試一次。

But by cleverly exploiting superposition and entanglement,

但透過巧妙地利用疊加態與糾纏態，

this can be exponentially more efficient than would ever be possible on a normal computer. 文法

這可以比一般電腦更加高效，呈指數級的提升。

So, while quantum computers will probably not replace our home computers,

因此，雖然量子電腦可能不會取代我們的家用電腦，

in some areas, they are vastly superior. 片語搭配

但在某些領域，它們具有極大的優勢。

One of them is database searching.

其中之一就是資料庫搜尋。

To find something in a database,

要在資料庫中尋找某個東西，

a normal computer may have to test every single one of its entries. 片語搭配

一般電腦可能要測試每一個項目。

Quantum algorithms need only the square root of that time, 文法

量子演算法只需要測試該時間平方根的次數，

which for large databases is a huge difference.

對於龐大的資料庫來說，這是一個巨大的差異。

The most famous use of quantum computers is ruining IT security.

量子電腦最著名的用途，就是摧毀資訊安全系統。

Right now, your browsing, email, and banking data

目前，你的瀏覽、電子郵件和銀行資料

is being kept secure by an encryption system 文法

都是由一個加密系統保護著，

in which you give everyone a public key 文化背景

在這個系統中，你給了每個人一把公鑰，

to encode messages only you can decode.

用來編碼只有你才能解碼的訊息。

The problem is that this public key

問題在於，這把公鑰

can actually be used to calculate your secret private key.

實際上可以用來計算你的秘密私鑰。

Luckily,

幸運的是，

doing the necessary math on any normal computer

在任何一般電腦上進行必要的數學計算，

would literally take years of trial and error. 講解

都需要耗費數年的反覆試錯。

But a quantum computer with exponential speedup

但一台具備指數級加速的量子電腦，

could do it in a breeze.

可以輕而易舉地完成。

Another really exciting new use is simulations.

另一個非常令人興奮的新用途是模擬。

Simulations of the quantum world are very intense on resources,

對量子世界進行模擬會極大地消耗資源，

and even for bigger structures such as molecules,

而且即便是對於像分子這樣較大的結構，

they often lack accuracy.

它們也往往缺乏準確性。

So, why not simulate quantum physics 語氣意圖

那麼，為什麼不使用真實的量子物理

with actual quantum physics?

來模擬量子物理呢？

Quantum simulations could provide new insights on proteins

量子模擬可以提供關於蛋白質的新見解，

that might revolutionize medicine.

從而可能徹底改變醫學。

Right now, we don't know if quantum computers 文法

目前，我們還不知道量子電腦

will be just a very specialized tool,

是只會成為一個非常專業的工具，

or a big revolution for humanity.

還是會成為人類的一場巨大革命。

We have no idea where the limits of technology are, 文法

我們完全不知道科技的極限在哪裡，

and there's only one way to find out. 片語搭配

要找到答案，只有一種方法。

This video is supported by the Australian Academy of Science,

本影片由澳洲科學院支持，

which promotes and supports excellence in science.

該機構旨在促進並支持科學界的卓越發展。

Learn more about this topic and others like it

了解更多關於此主題及其他類似主題的資訊，

at nova.org.au.

請造訪 nova.org.au。

It was a blast to work with them. 慣用語

與他們合作非常愉快。

So, go check out their site.

所以，去看看他們的網站吧。

Our videos are also made possible by your support on patreon.com. 片語搭配

我們的影片也得益於你們在 patreon.com 上的支持才得以製作。

If you want to support us

如果你想支持我們，

and become part of the Kurzgesagt bird army,

並成為 Kurzgesagt 鳥類大軍的一員，

check out our Patreon page.

請造訪我們的 Patreon 頁面。