量子計(jì)算機(jī)（quantum computer）是一類遵循量子力學(xué)規(guī)律進(jìn)行高速數(shù)學(xué)和邏輯運(yùn)算、存儲及處理量子信息的物理裝置。當(dāng)某個(gè)裝置處理和計(jì)算的是量子信息，運(yùn)行的是量子算法時(shí)，它就是量子計(jì)算機(jī)。量子計(jì)算機(jī)的概念源于對可逆計(jì)算機(jī)的研究。研究可逆計(jì)算機(jī)的目的是為了解決計(jì)算機(jī)中的能耗問題。
量子計(jì)算機(jī)光從百度百科上給出的內(nèi)容看的話會(huì)讓我們云里霧里。今天的TED演講將會(huì)用十分鐘的時(shí)間生動(dòng)地讓我們了解什么是量子計(jì)算機(jī)。
演講內(nèi)容如下
Let’s play a game.
咱們來玩?zhèn)€游戲。
Imagine that you are in Las Vegas,
想像你在拉斯維加斯，
in a casino,
在一間賭場裡，
and you decide to play a game on one of the casino’s computers,
你決定在其中一臺電腦上玩游戲，
just like you might play solitaire or chess.
就像是玩紙牌或是下棋。
The computer can make moves in the game, just like a human player.
電腦也能移動(dòng)游戲中的棋子， 和人類玩家一樣。
This is a coin game.
這是一個(gè)硬幣游戲。
It starts with a coin showing heads,
一開始，有一枚正面朝上的硬幣，
and the computer will play first.
開局后，電腦先玩。
It can choose to flip the coin or not,
它可以選擇是否拋擲這枚硬幣，
but you don’t get to see the outcome.
但你不會(huì)知道結(jié)果如何。
Next, it’s your turn.
接著就輪到你。
You can also choose to flip the coin or not,
你也可以選擇是否拋擲這枚硬幣，
and your move will not be revealed to your opponent, the computer.
你的對手，也就是電腦， 同樣不會(huì)知道這一輪的結(jié)果。
Finally, the computer plays again, and can flip the coin or not,
最后，又輪到電腦 選擇是否拋擲硬幣，
and after these three rounds,
經(jīng)過三輪游戲之后，
the coin is revealed,
硬幣的狀態(tài)被揭示出來，
and if it is heads, the computer wins,
如果是正面朝上，就是電腦贏，
if it’s tails, you win.
如果是反面朝上，就是你贏。
So it’s a pretty simple game,
這是個(gè)很簡單的游戲，
and if everybody plays honestly, and the coin is fair,
如果大家都不作弊， 且硬幣也是均勻的，
then you have a 50 percent chance of winning this game.
那么你就有 50% 的機(jī)會(huì)獲勝。
And to confirm that,
為了確認(rèn)這一點(diǎn)，
I asked my students to play this game on our computers,
我讓我的學(xué)生用我們的 電腦來玩這個(gè)游戲，
and after many, many tries,
在嘗試非常非常多次之后，
their winning rate ended up being 50 percent, or close to 50 percent,
他們的勝率最后是 50% 或接近 50%，
as expected.
和預(yù)期的一樣。
Sounds like a boring game, right?
聽起來很無聊，對吧？
But what if you could play this game on a quantum computer?
但如果你能用量子電腦 來玩這個(gè)游戲，會(huì)怎樣？
Now, Las Vegas casinos do not have quantum computers,
拉斯維加斯的賭場可沒有量子電腦，
as far as I know,
據(jù)我所知是這樣，
but IBM has built a working quantum computer.
但 IBM 已經(jīng)打造出了一臺 能夠正常運(yùn)轉(zhuǎn)的量子電腦。
Here it is.
就是它。
But what is a quantum computer?
但是，量子電腦是什麼？
Well, quantum physics describes
嗯，量子物理是在描述
the behavior of atoms and fundamental particles,
原子和基本粒子的行為，
like electrons and photons.
比如電子和光子。
So a quantum computer operates
所以，量子電腦的運(yùn)作方式
by controlling the behavior of these particles,
在于控制這些粒子的行為，
but in a way that is completely different from our regular computers.
但其做法和普通的電腦完全不同。
So a quantum computer is not just a more powerful version
量子電腦并不只是
of our current computers,
我們目前電腦的加強(qiáng)版，
just like a light bulb is not a more powerful candle.
就好像電燈泡并不是加強(qiáng)版的蠟燭。
You cannot build a light bulb by building better and better candles.
無論如何，蠟燭也不可能變成電燈泡。
A light bulb is a different technology,
電燈泡使用了一種不同的技術(shù)，
based on deeper scientific understanding.
它的基礎(chǔ)是更深入的科學(xué)理解。
Similarly, a quantum computer is a new kind of device,
同樣地，量子電腦也是一種新裝置，
based on the science of quantum physics,
以量子物理為根據(jù)，
and just like a light bulb transformed society,
就如同電燈泡改變了人類社會(huì)，
quantum computers have the potential to impact
量子電腦也有潛力影響
so many aspects of our lives,
我們生活的方方面面，
including our security needs, our health care and even the internet.
包括我們的安全需求、 我們的醫(yī)療保健，甚至網(wǎng)際網(wǎng)路。
So companies all around the world are working to build these devices,
全世界的公司都在打造這類裝置。
and to see what the excitement is all about,
要想看看它有多讓人興奮，
let’s play our game on a quantum computer.
咱們來用量子電腦玩這個(gè)游戲。
So I can log into IBM’s quantum computer from right here,
我可以從這裡登入到 IBM 的量子電腦，
which means I can play the game remotely,
也就表示我可以從遠(yuǎn)端玩這個(gè)游戲，
and so can you.
你也可以做到。
To make this happen, you may remember getting an email ahead of time, from TED,
為了讓你們參與進(jìn)來，你們可能記得，
asking you whether you would choose to flip the coin or not,
先前有收到 TED 寄的電子郵件，信上請你選擇，
if you played the game.
如果你在玩這個(gè)游戲，
Well, actually, we asked you to choose between a circle or a square.
是否會(huì)選擇拋擲硬幣。事實(shí)上，我們在信上 是請你選擇圓形或方形。
You didn’t know it, but your choice of circle meant "flip the coin,"
你當(dāng)時(shí)并不知道，選擇圓形 就表示「擲硬幣」，
and your choice of square was "don’t flip."
選擇方形就表示「不要擲」。
We received 372 responses.
我們收到了 372 個(gè)人的回覆。
Thank you.
謝謝你們。
That means we can play 372 games against the quantum computer
那就表示，我們可以用你們的選擇，
using your choices.
跟量子電腦玩 372 場游戲。
And it’s a pretty fast game to play,
這個(gè)游戲一下就結(jié)束了，
so I can show you the results right here.
所以我可以把結(jié)果呈現(xiàn)在這裡。
Unfortunately, you didn’t do very well.
不幸的是，你們的戰(zhàn)績不太好。
(Laughter)
（笑聲）
The quantum computer won almost every game.
量子電腦幾乎全勝。
It lost a few only because of operational errors in the computer.
它輸了幾場，只是因?yàn)?電腦中的運(yùn)算錯(cuò)誤。
(Laughter)
（笑聲）
So how did it achieve this amazing winning streak?
所以，它是如何取得 這驚人的一連串勝利的？
It seems like magic or cheating,
它就像魔術(shù)或作弊一樣，
but actually, it’s just quantum physics in action.
但事實(shí)上，它只是量子物理的運(yùn)作。
Here’s how it works.
它的運(yùn)作方式如下。
A regular computer simulates heads or tails of a coin as a bit,
普通電腦用一個(gè)位元來 模擬硬幣的正反面，
a zero or a one,
即 0 或是 1，
or a current flipping on and off inside your computer chip.
或記錄當(dāng)前是否選擇拋擲硬幣， 儲存在你的電腦晶片中。
A quantum computer is completely different.
量子電腦則完全不同。
A quantum bit has a more fluid, nonbinary identity.
一個(gè)量子位元更具有 不固定性、非二進(jìn)制的特質(zhì)。
It can exist in a superposition, or a combination of zero and one,
它能存在于量子疊加態(tài)當(dāng)中， 即 0 和 1 的組合當(dāng)中，
with some probability of being zero and some probability of being one.
既有可能是 0，也有可能是 1。
In other words, its identity is on a spectrum.
換言之，它的真面目其實(shí)是一個(gè)范圍。
For example, it could have a 70 percent chance of being zero
比如，它可能有 70% 的概率是 0，
and a 30 percent chance of being one
30% 的概率是 1，
or 80-20 or 60-40.
或 80% 與 20%， 60% 與 40%等。
The possibilities are endless.
存在無限的可能性。
The key idea here
這裡的關(guān)鍵在于，
is that we have to give up on precise values of zero and one
我們得要捨棄「只存在固定的 0 和 1」 的思考方式，
and allow for some uncertainty.
允許不確定性存在。
So during the game,
在游戲期間，
the quantum computer creates this fluid combination of heads and tails,
量子電腦會(huì)創(chuàng)造出正反兩面
zero and one,
（0 和 1）的不固定性組合，
so that no matter what the player does,
所以，不論玩家選擇什麼，
flip or no flip,
不論擲或不擲硬幣，
the superposition remains intact.
這種 量子疊加態(tài)并不會(huì)改變。
It’s kind of like stirring a mixture of two fluids.
這有點(diǎn)像是在攪拌兩種液體。
Whether or not you stir, the fluids remain in a mixture,
不論你攪或不攪， 兩種液體都混合在一起。
but in its final move,
但在它的最后一輪游戲中，
the quantum computer can unmix the zero and one,
量子電腦能分離出 0 和 1，
perfectly recovering heads so that you lose every time.
將硬幣完美地恢復(fù)成正面朝上， 所以你每次都會(huì)輸。
(Laughter)
（笑聲）
If you think this is all a bit weird, you are absolutely right.
如果你覺得這一切十分怪異， 那你一點(diǎn)兒也沒錯(cuò)。
Regular coins do not exist in combinations of heads and tails.
普通硬幣并不會(huì)以正面 和反面的組合形式存在。
We do not experience this fluid quantum reality
我們在日常生活中并不會(huì)經(jīng)歷
in our everyday lives.
這種不固定的、量子化的現(xiàn)實(shí)。
So if you are confused by quantum,
所以，如果量子讓你困惑不解，
don’t worry, you’re getting it.
別擔(dān)心，你其實(shí)正在明白它。
(Laughter)
（笑聲）
But even though we don’t experience quantum strangeness,
但是，雖然我們沒有 切身體驗(yàn)量子的不可思議，
we can see its very real effects in action.
我們可以看到它產(chǎn)生了 非常真實(shí)的影響。
You’ve seen the data for yourself.
你們已經(jīng)親眼看到資料了。
The quantum computer won
量子電腦會(huì)贏，
because it harnessed superposition and uncertainty,
是因?yàn)樗昧孔盈B加態(tài)和不確定性，
and these quantum properties are powerful,
這些量子特性非常強(qiáng)大，
not just to win coin games,
不僅能幫你贏得硬幣游戲，
but also to build future quantum technologies.
也能用來建造未來的量子科技。
So let me give you three examples of potential applications
讓我舉三個(gè)例子， 說明那些有潛力的科技應(yīng)用，
that could change our lives.
它們有可能改變我們的生活。
First of all, quantum uncertainty could be used to create private keys
首先，量子不確定性
for encrypting messages sent from one location to another
可用于私鑰加密，
so that hackers could not secretly copy the key perfectly,
將兩地之間傳輸?shù)挠嵪⑦M(jìn)行加密，
because of quantum uncertainty.
因?yàn)榱孔硬淮_定性，
They would have to break the laws of quantum physics
駭客就無法偷偷地複製完整密鑰。
to hack the key.
他們?nèi)粝氡I用密鑰，
So this kind of unbreakable encryption is already being tested by banks
就得打破量子物理的法則。
and other institutions worldwide.
全世界的銀行和其他機(jī)構(gòu)已經(jīng)在測試
Today, we use more than 17 billion connected devices globally.
這種牢不可破的加密。
Just imagine the impact quantum encryption could have in the future.
現(xiàn)今，全球使用了超過 170 億個(gè)接入網(wǎng)路的裝置。
Secondly, quantum technologies could also transform health care and medicine.
想像一下，量子加密 在未來會(huì)有怎樣的影響。
For example, the design and analysis of molecules for drug development
第二，量子科技也能轉(zhuǎn)變 醫(yī)療保健和醫(yī)學(xué)。
is a challenging problem today,
比如，在藥物開發(fā)中， 設(shè)計(jì)和分析各種分子
and that’s because exactly describing and calculating
是現(xiàn)今很具挑戰(zhàn)性的問題，
all of the quantum properties of all the atoms in the molecule
這是因?yàn)椋_地描述和計(jì)算
is a computationally difficult task, even for our supercomputers.
分子中所有原子的全部量子特性，
But a quantum computer could do better,
是非常難以計(jì)算的， 即使對于超級電腦也同樣。
because it operates using the same quantum properties
但量子電腦能做得更好，
as the molecule it’s trying to simulate.
因?yàn)樗c它試圖模擬的分子一樣，
So future large-scale quantum simulations for drug development
使用了相同的量子特性來進(jìn)行計(jì)算，
could perhaps lead to treatments for diseases like Alzheimer’s,
因此，對于藥物開發(fā)， 未來的大規(guī)模量子模擬
which affects thousands of lives.
也許可以為阿茲海默癥 之類的疾病找到治療方式，
And thirdly, my favorite quantum application
影響成千上萬的人。
is teleportation of information from one location to another
第三，是我最喜愛的量子應(yīng)用，
without physically transmitting the information.
是將資訊從一個(gè)地點(diǎn) 即時(shí)傳遞到另一個(gè)地點(diǎn)，
Sounds like sci-fi, but it is possible,
但不需要實(shí)際傳遞。
because these fluid identities of the quantum particles
聽起來很科幻，但這是有可能的，
can get entangled across space and time
因?yàn)榱孔恿Ｗ拥倪@些不固定特質(zhì)
in such a way that when you change something about one particle,
在時(shí)間和空間中 可能會(huì)糾纏在一起，
it can impact the other,
以至于當(dāng)你改變了 其中的某一個(gè)粒子，
and that creates a channel for teleportation.
就會(huì)同時(shí)影響到其他粒子的狀態(tài)， 這就成了量子通信的「通道」。
It’s already been demonstrated in research labs
在研究實(shí)驗(yàn)室裡已經(jīng)展示它可行，
and could be part of a future quantum internet.
可能會(huì)成為未來量子 網(wǎng)際網(wǎng)路的一部分。
We don’t have such a network as yet,
我們目前尚無這樣的網(wǎng)路，
but my team is working on these possibilities,
但我的團(tuán)隊(duì)正在努力實(shí)現(xiàn)它，
by simulating a quantum network on a quantum computer.
我們會(huì)在一臺量子電腦上 模擬一個(gè)量子網(wǎng)路。
So we have designed and implemented some interesting new protocols
我們已經(jīng)設(shè)計(jì)并實(shí)現(xiàn)了 一些有趣的、新的通訊協(xié)議，
such as teleportation among different users in the network
比如在網(wǎng)路上不同 用戶之間傳輸訊息，
and efficient data transmission
以及高效的文件傳輸，
and even secure voting.
甚至還有安全的選舉投票。
So it’s a lot of fun for me, being a quantum physicist.
因此，我身為量子物理學(xué)家， 覺得這非常有意思。
I highly recommend it.
我極力推薦它。
(Laughter)
（笑聲）
We get to be explorers in a quantum wonderland.
我們有機(jī)會(huì)在量子仙境中當(dāng)探險(xiǎn)家。
Who knows what applications we will discover next.
誰知道接下來我們 會(huì)發(fā)現(xiàn)什麼新應(yīng)用。
We must tread carefully and responsibly
當(dāng)我們打造量子未來時(shí)，
as we build our quantum future.
我們必須要謹(jǐn)慎且可靠地向前邁進(jìn)。
And for me, personally,
對我個(gè)人來說，
I don’t see quantum physics as a tool just to build quantum computers.
我認(rèn)為量子物理并不只是 用來打造量子電腦的工具。
I see quantum computers as a way for us to probe the mysteries of nature
我認(rèn)為量子電腦能協(xié)助我們 探索大自然的謎題，
and reveal more about this hidden world outside of our experiences.
并更深入地揭示出我們 無法體驗(yàn)的隱秘世界。
How amazing that we humans,
這是多麼不可思議，我們?nèi)祟?/span>
with our relatively limited access to the universe,
對于宇宙的認(rèn)識 和接觸是相對受限的，
can still see far beyond our horizons
我們卻單單靠著想像力和獨(dú)創(chuàng)性，
just using our imagination and our ingenuity.
仍然能觀察到遠(yuǎn)遠(yuǎn) 高于我們眼界的地方。
And the universe rewards us
而宇宙給我們的獎(jiǎng)賞
by showing us how incredibly interesting and surprising it is.
就是讓我們看到它是 多麼有趣、讓人驚奇。
The future is fundamentally uncertain,
未來，本來就是不確定的，
and to me, that is certainly exciting.
但對我來說，我很確定， 它是讓人興奮的。
Thank you.
謝謝。
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