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Let's play a game. Imagine that you are in Las Vegas, in a casino,
我们来玩个游戏。假设你现在在拉斯维加斯的一个赌场里，
and you decide to play a game on one of the casino's computers, just like you might play solitaire or chess.
而且你决定要在赌场内的某台电脑上玩游戏，你可能会玩纸牌或者象棋。
The computer can make moves in the game, just like a human player.
电脑能像真人玩家一样，在游戏中出牌或走棋。
This is a coin game. It starts with a coin showing heads, and the computer will play first.
这是一个硬币游戏。首先，一个硬币正面朝上，电脑会先开始玩。
It can choose to flip the coin or not, but you don't get to see the outcome.
电脑可以选择把硬币翻过来或者不翻，但是你看不到结果。
Next, it's your turn. You can also choose to flip the coin or not,
接下来就轮到你了。你也可以选择把硬币翻过来或者不翻，
and your move will not be revealed to your opponent, the computer.
而你的选择不会被透露给你的对手（电脑）。
Finally, the computer plays again, and can flip the coin or not,
接下来，又轮到电脑做选择：把硬币翻过来或者不翻，
and after these three rounds, the coin is revealed,
三轮过后，硬币的朝向会被揭晓，
and if it is heads, the computer wins, if it's tails, you win.
如果正面朝上，那电脑就赢了；如果反面朝上，那你就赢了。
So it's a pretty simple game, and if everybody plays honestly,
这是一个非常简单的游戏，如果每个人都老实参与游戏，
and the coin is fair, then you have a 50 percent chance of winning this game.
而且硬币也是质地均匀的，那你赢得这场游戏的概率是50%。
And to confirm that, I asked my students to play this game on our computers,
为了确认这一点，我让我的学生在我们的电脑上玩了这个游戏，
and after many, many tries, their winning rate ended up being 50 percent, or close to 50 percent, as expected.
尝试了很多很多次之后，他们的获胜率恰巧为50%或者接近50%，意料之中。
Sounds like a boring game, right?
这个游戏听起来有些无聊，是吧？
But what if you could play this game on a quantum computer?
但是，如果你能在量子计算机上玩这个游戏，那会怎样呢？
Now, Las Vegas casinos do not have quantum computers, as far as I know,
目前，据我所知，拉斯维加斯的赌场并没有量子计算机，
but IBM has built a working quantum computer. Here it is.
不过IBM已经制造了一台可以正常运行的量子计算机。就是这台。
But what is a quantum computer?
什么是量子计算机呢？
Well, quantum physics describes the behavior of atoms and fundamental particles, like electrons and photons.
量子力学研究原子和基本粒子，如电子、光子的运动规律。
So a quantum computer operates by controlling the behavior of these particles,
量子计算机通过控制这些粒子的运动来实现运行，
but in a way that is completely different from our regular computers.
但其运行方式与普通电脑截然不同。
So a quantum computer is not just a more powerful version of our current computers,
量子计算机可不只是现有电脑的加强版，
just like a light bulb is not a more powerful candle.
就像电灯泡不是蜡烛的加强版一样。
You cannot build a light bulb by building better and better candles.
即使你不断地改良蜡烛，也做不出电灯泡。
A light bulb is a different technology, based on deeper scientific understanding.
电灯泡需要完全不同的技术，基于更深层次的科学认识。
Similarly, a quantum computer is a new kind of device, based on the science of quantum physics,
同样，量子计算机是一种基于量子力学的全新设备；
and just like a light bulb transformed society,
就像电灯泡带来了社会变革，
quantum computers have the potential to impact so many aspects of our lives,
量子计算机也很可能会影响人类生活的方方面面，
including our security needs, our health care and even the internet.
如安全需求、卫生保健、甚至是互联网。
So companies all around the world are working to build these devices,
因此，全球数家公司正在研发量子计算机，
and to see what the excitement is all about, let's play our game on a quantum computer.
量子计算机究竟为何让我们如此激动？我们在量子计算机上玩个游戏看看。
So I can log into IBM's quantum computer from right here,
我可以就地登入IBM的量子计算机，
which means I can play the game remotely, and so can you.
也就是说，我可以远程玩游戏，你也可以。
To make this happen, you may remember getting an email ahead of time, from TED,
首先，要记得提前从TED获得一个邮箱，
asking you whether you would choose to flip the coin or not, if you played the game.
你参与游戏的话，邮箱信息会问你是否要翻转硬币。
Well, actually, we asked you to choose between a circle or a square.
实际上，我们会问你要选圆圈还是方块。
You didn't know it, but your choice of circle meant "flip the coin," and your choice of square was "don't flip."
你事先并不知道，不过你选圆圈就是要把硬币翻面，你选方块就是不翻面。
We received 372 responses. Thank you.
我们收到了372条回复。在此要谢谢大家的参与。
That means we can play 372 games against the quantum computer using your choices.
这意味着我们可以用你们的选择跟量子计算机玩372把游戏。
And it's a pretty fast game to play, so I can show you the results right here.
这个游戏很快就能结束，我现在就可以给你们看结果。
Unfortunately, you didn't do very well.
不幸的是，你们运气不太好。
The quantum computer won almost every game.
量子计算机在每轮游戏中基本都会赢。
It lost a few only because of operational errors in the computer.
只输了几把，而这是计算机自身的操作错误造成的。
So how did it achieve this amazing winning streak?
那么，量子计算机怎么能够如此惊人的接连获胜呢？
It seems like magic or cheating, but actually, it's just quantum physics in action.
看起来像是魔术或作弊一样，但实际上，这是因为量子力学在发挥作用。
Here's how it works. A regular computer simulates heads or tails of a coin as a bit, a zero or a one,
操作如下。普通计算机用比特模仿硬币的正面或反面，即0或者1，
or a current flipping on and off inside your computer chip.
或是用电脑芯片内的电流供断来模仿。
A quantum computer is completely different. A quantum bit has a more fluid, nonbinary identity.
量子计算机则全然不同。量子比特更易变，具有非二进制特性。
It can exist in a superposition, or a combination of zero and one,
能以0和1叠加，或者说组合的形式存在，
with some probability of being zero and some probability of being one.
有可能为0，有可能为1。
In other words, its identity is on a spectrum.
换句话说，其特性处于一个范围内。
For example, it could have a 70 percent chance of being zero and a 30 percent chance of being one or 80-20 or 60-40.
比如说，它有70%的可能性是0和30%的可能性是1，也可能是八二分或六四分。
The possibilities are endless.
有无穷的可能性。
The key idea here is that we have to give up on precise values of zero and one and allow for some uncertainty.
关键是我们需要放弃绝对的0和1，接受一些不确定性。
So during the game, the quantum computer creates this fluid combination of heads and tails, zero and one,
所以在玩游戏时，量子计算机创造了正面和反面，即0和1的易变组合，
so that no matter what the player does, flip or no flip, the superposition remains intact.
所以不论玩家怎么选，将硬币翻面与否，叠加均不受影响。
It's kind of like stirring a mixture of two fluids.
就像是搅拌两种液体的混合物。
Whether or not you stir, the fluids remain in a mixture, but in its final move,
不论你搅拌与否，两种液体仍在混合物中，但是在最后一步，
the quantum computer can unmix the zero and one, perfectly recovering heads so that you lose every time.
量子计算机可以把混合的0和1分开，让硬币正面朝上，所以你每次都赢不了。
If you think this is all a bit weird, you are absolutely right.
如果你觉得这很奇怪，那就对了。
Regular coins do not exist in combinations of heads and tails.
普通硬币并没有两面同时朝上这种状态。
We do not experience this fluid quantum reality in our everyday lives.
我们在日常生活中也从未经历过这种不确定的量子实际状态。
So if you are confused by quantum, don't worry, you're getting it.
所以如果你对量子感到困惑，不用担心，你终究会明白的。
But even though we don't experience quantum strangeness, we can see its very real effects in action.
不过即便我们没有见识过量子的奇特之处，我们还是能看到其实实在在的影响。
You've seen the data for yourself.
你们也亲眼看到游戏结果了。
The quantum computer won because it harnessed superposition and uncertainty,
量子计算机赢了，因为量子计算机利用了叠加和不确定性，
and these quantum properties are powerful, not just to win coin games,
而这些量子特性非常强大，不仅仅能在硬币游戏中获胜，
but also to build future quantum technologies.
也能创造未来的量子技术。
So let me give you three examples of potential applications that could change our lives.
量子技术的潜在应用能够改变我们的生活，我来举三个例子。
First of all, quantum uncertainty could be used to create private keys for encrypting messages sent from one location to another
首先，量子不确定性可以用来创造私钥，将从一个地方发到另一个地方的信息加密，
so that hackers could not secretly copy the key perfectly, because of quantum uncertainty.
这样黑客就不能偷偷完全复制这个私钥了，就是因为量子具有不确定性。
They would have to break the laws of quantum physics to hack the key.
要想获得私钥，黑客得先打破量子力学法则。
So this kind of unbreakable encryption is already being tested by banks and other institutions worldwide.
目前全球银行和其他机构已经在测试这种无法破解的加密方法了。
Today, we use more than 17 billion connected devices globally.
当前，全球的联网设备多达170亿台。
Just imagine the impact quantum encryption could have in the future.
大家可以试想一下量子加密在未来的影响力会有多大。
Secondly, quantum technologies could also transform health care and medicine.
其次，量子技术也能改变医疗保健和医药行业。
For example, the design and analysis of molecules for drug development is a challenging problem today,
比如，在药物研发过程中设计和分析分子迄今仍是一个极具挑战的难题，
and that's because exactly describing and calculating all of the quantum properties of all the atoms in the molecule
因为要准确描述和计算分子中所有原子的所有量子特性，
is a computationally difficult task, even for our supercomputers.
从计算角度而言是一个极难的任务，对于我们的超级计算机而言也不例外。
But a quantum computer could do better,
但是量子计算机更胜一筹，
because it operates using the same quantum properties as the molecule it's trying to simulate.
因为量子计算机运行时运用了与其试图模拟的分子相同的量子特性。
So future large-scale quantum simulations for drug development
所以在未来的药物研发中，大规模量子模拟
could perhaps lead to treatments for diseases like Alzheimer's, which affects thousands of lives.
或许有助于治疗影响成千上万人的疾病，如阿尔兹海默症。
And thirdly, my favorite quantum application is teleportation of information
第三，我个人最喜欢的量子应用是量子瞬移，
from one location to another without physically transmitting the information.
即将信息从一个地点传送到另一个地点，而不需要实际的传播途径。
Sounds like sci-fi, but it is possible, because these fluid identities of the quantum particles
听起来就像科幻小说，但这是可能实现的，因为这些量子粒子的易变特性
can get entangled across space and time in such a way that when you change something about one particle,
能跨越时空发生纠缠，这样你更改一个粒子的某些东西时，
it can impact the other, and that creates a channel for teleportation.
也会影响另一个粒子，这就创造出了量子瞬移通道。
It's already been demonstrated in research labs and could be part of a future quantum internet.
研究实验室已经就此进行了证实，这将构成未来量子网络的一部分。
We don't have such a network as yet, but my team is working on these possibilities,
我们现在还没有这样的网络，不过我的团队正在为了这些可能性而努力，
by simulating a quantum network on a quantum computer.
在量子计算机上模拟量子网络。
So we have designed and implemented some interesting new protocols
我们设计实施了一些有趣的新网络协议，
such as teleportation among different users in the network and efficient data transmission and even secure voting.
如不同网络用户间的量子瞬移和高效数据传输，甚至还包括安全投票。
So it's a lot of fun for me, being a quantum physicist. I highly recommend it.
当一名量子物理学家，我觉得很好玩，也极力推荐大家跟随我的脚步。
We get to be explorers in a quantum wonderland. Who knows what applications we will discover next.
让我们一同探索神奇的量子世界。谁知道接下来我们又会发现什么样的应用呢？
We must tread carefully and responsibly as we build our quantum future.
打造量子未来时，我们务必要谨慎负责。
And for me, personally, I don't see quantum physics as a tool just to build quantum computers.
就我个人而言，我并不只把量子力学当做是制造量子计算机的工具。
I see quantum computers as a way for us to probe the mysteries of nature and reveal more about this hidden world outside of our experiences.
而是将使用量子计算机视作探索自然奥秘、揭示未知世界的方法。
How amazing that we humans, with our relatively limited access to the universe,
人类是多么的伟大，虽然我们了解浩瀚宇宙的渠道有限，
can still see far beyond our horizons just using our imagination and our ingenuity.
但是凭我们的想象力与创造力，我们能够不断拓宽视野。
And the universe rewards us by showing us how incredibly interesting and surprising it is.
而浩瀚的宇宙会也会回报我们，向我们展示它有趣又惊艳的一面。
The future is fundamentally uncertain, and to me, that is certainly exciting. Thank you.
从根本上来说，未来具有不确定性；对我来说，这着实激动人心。谢谢大家。
