Quantum Computers Aren’t What You Think — They’re Cooler | Hartmut Neven | TED

翻译人员: Yip Yan Yeung

I'm Hartmut, I lead Google Quantum AI.

我是哈特穆特（Hartmut）， 我领导着谷歌量子 AI。

I have been working on quantum computing since 2012.

自 2012 年以来， 我一直在研究量子计算。

And let me tell you why this is so intriguing.

我来告诉你 为什么这如此有趣。

Today's computers, like your laptop or a server at a Google data center,

如今的计算机，比如笔记本电脑 或谷歌数据中心的服务器，

operate on the binary logic of zeros and ones.

都基于 0 和 1 的二进制逻辑运行。

A quantum computer like this one replaces the binary logic

像这样的量子计算机 取代了二进制逻辑，

with the laws of quantum physics that gives it more powerful operations,

借助量子物理定律 ， 这赋予了它更强大的运算，

allowing it to perform certain computations with way fewer steps.

以更少的步骤进行某些计算。

So where does this superpower come from?

那么这种超级计算能力从何而来呢？

Quantum computing is the first technology

量子计算是第一项

that takes the idea serious that we live in a multiverse.

正视“我们生活在多重宇宙中” 这一概念的技术。

It can be seen as farming out computations to parallel universes.

可以看作将计算借给平行宇宙。

Let me explain.

我来解释一下。

In quantum physics,

在量子物理学中，

the key mathematical object

描述许多世界的关键数学对象 称为“叠加”。

to describe many worlds is called superposition.

To understand what it is, let's look at this simple system.

要了解它是什么， 我们来看看这个简单的系统。

You just need three bits to describe it.

只需要三位就能描述它。

Each coin is a two-state system.

每枚硬币都是一个双态系统。

Heads or tails,

正面或反面，

zero or one.

零或一。

We look at a start state.

我们来看一下起始状态。

If I were to know which forces act on the system,

如果我知道哪些力作用于系统，

then I can predict its trajectory and future states.

那我就能预测它的轨迹 和未来的状态。

This is how we reason in classical physics and also in everyday life.

这就是我们在经典物理学 和日常生活中的推理方式。

But if you were to treat this as a quantum system,

但是，如果你 将其视为量子系统，

then it can branch into many configurations simultaneously.

那么它可以同时分化成多种组态。

And we have to keep track of all those trajectories,

我们必须追踪所有轨迹，

interfere them to make an accurate prediction

对其进行干预，以便准确预测

of what states we are going to see in the future.

未来将要看到的状态。

So the equations of quantum mechanics

量子力学方程

tell us that at any time, any object,

告诉我们， 无论何时，任何物体，

myself or the world at large,

我自己或是整个世界，

exists in a superposition of many configurations.

都以各种组态的叠加形态存在。

Intriguingly, look around in this room.

有趣的是，环顾这个房间。

We are forming a configuration too.

我们也构成了组态。

And the equations of quantum physics would suggest

量子物理学的方程

that we sit in different arrangements in different worlds.

表明我们在不同世界里 处在不同的位置中。

This superpower can be applied to computation.

这种超能力可以应用于计算。

Picture a search task.

想象一下搜索任务。

By envisioning a very tall closet with a million drawers,

想象有一个很高的柜子， 上面有一百万个抽屉，

I place an item in one of the drawers.

我在其中一个抽屉里 放了一件物品。

How many drawers do you have to open to find the item?

你得打开多少个抽屉才能找到它？

In average it will be half a million,

平均 50 万个，

but if you had access to a quantum algorithm,

但是如果你可以使用量子算法，

it would only be 1,000 steps to find the item.

那么找到该物品只需要一千步。

How in the world can this be?

在这样的世界中，会是什么样的？

Indeed, it cannot be in a single world.

它不可能存在于单一世界中。

So here you see a good example

这里有一个很好的例子，

of how quantum computing can attain an advantage

说明量子计算如何通过在平行世界中 进行计算来取得优势。

by performing computations in parallel worlds.

Let me show you how to use a quantum computer in practice.

我来展示量子计算机是怎么用的。

So here you see a program in Cirq,

这是一个用 Cirq 语言编写的程序，

or Python-based programming language to express quantum algorithms.

Cirq 是基于 Python， 用于表达量子算法的编程语言。

It looks like sheet music.

就像乐谱一样。

Each line represents a qubit,

每行代表一个量子比特，

and each box represents an operation.

每个方框代表一个运算。

When I hit return,

点击返回，

then it gets transmitted to our data center

它会被传输到我们 位于圣塔芭芭拉的数据中心。

in Santa Barbara.

Here you actually see a live feed of one of our machines.

这就是其中一台机器的现场直播。

Actually, our most powerful quantum computers now have over 100 qubits.

我们最强大的量子计算机 现在有超过 100 个量子比特。

There, the operations get translated into waveforms,

运算在此被转换为波形，

electrical pulses that control the qubits.

即控制量子比特的电脉冲。

You see how the waveforms change as I change the circuit.

你可以看到我改变电路时 波形是如何变化的。

So this is a simple two-qubit circuit performing quantum search.

这就是一个执行量子搜索的 简单双量子位电路。

For the programmers among you,

对在座的程序员来说，

please note how I find one item in a database of four

请注意我如何在包含四个条目的 数据库中找到一个条目，

by only doing a single call to the database.

只通过对数据库的一次调用。

This is something you could not do on an ordinary computer.

这是你在普通计算机上无法做到的。

So what can you do with quantum computers today?

你现在能用量子计算机做些什么呢？

We have prepared interesting quantum states

我们已经准备了有趣的量子态，

and studied their properties.

研究了它们的性质。

This has led to dozens of publications

在《自然》或《科学》等高影响力期刊上 发表了数十篇文章。

in high-impact journals like Nature or Science.

Actually, I like to think of it as creating little pieces of magic.

我其实喜欢把它看作是创造小魔法。

For example, one state we prepared

比如我们准备的一个状态

can be thought of as spawning a tiny traversable wormhole.

可以看作生成了一个 可以穿越的小虫洞。

We can use it to learn about the physics of wormholes.

我们可以用它来学习虫洞的物理学。

We can throw a qubit in

我们可以把一个量子比特放进去，

and see how it reappears on the other side.

看看它是如何重新出现在另一边的。

We made time crystals.

我们制作了时间晶体。

That's a cool word, isn't it?

很酷的词，不是吗？

Like, who doesn't want to have a time crystal as an earring?

谁不想把时间晶体当耳环戴？

Time crystals have amazing physical properties.

时间晶体具有惊人的物理特性。

They change periodically in time without ever exchanging energy

它们会定期发生变化， 而不会与环境交换能量。

with the environment.

That's the closest to a perpetual mobile

这是物理定律能产生 最接近永动机的东西。

that the laws of physics allow you to get.

Or a final example, non-abelian anyons.

或者最后一个例子， 非阿贝尔任意子。

This is a mouthful,

听起来很拗口，

but these are systems that change the overall properties

但这些系统可以 在交换两个相同的部分时

when exchanging two identical parts,

改变整体特性，

something humans have never seen before.

这是人类从未见过的。

Because envision a little house made of Lego bricks

想象一座由乐高积木制成的小房子，

and envision swapping two bricks that look identical.

想象交换两块看起来相同的积木。

In everyday life, you would not notice a difference,

在日常生活中， 你不会注意到任何区别，

but quantum physicists had predicted that systems can exist,

但是量子物理学家预测 这样的系统可以存在，

that exchange or change their properties

当你交换两个相同的部分时

when you exchange two identical parts.

它们会交换或改变其特性。

To date, nobody has performed

迄今为止，还没有人

a practical application that can only be done on a quantum computer.

进行过只能在量子计算机上 完成的实际应用。

Despite what you may have read in the press.

尽管你可能在媒体上看到过。

But today, I'm excited to tell you that we are completing the design

但是今天，我很兴奋地告诉你， 我们正要完成一种算法的设计，

of an algorithm that may lead to first commercial applications.

该算法可能会带来首款商业应用。

This quantum algorithm performs signal processing

这种量子算法执行信号处理，

to enable new ways to detect and analyze molecules

利用核电子自旋光谱学

using nuclear electronic spin spectroscopy.

提供了检测、分析分子的新方法。

In time, this may lead to exciting consumer applications.

不日可能会带来惊艳的消费型应用。

Envision a device akin to an electronic nose

想象一款设备，类似于你的手机 或智能手表中的电子鼻子。

in your phone or smart watch.

Wouldn't it be awesome if your phone could warn you

如果你的手机可以在你走进 充满危险病毒的房间时

that you step into a room with dangerous viruses?

警告你，不是很棒吗？

Or if your smart watch could detect free radicals in your bloodstream

如果你的智能手表 能检测到血液中的自由基，

and tell you it's time to drink your acai juice,

告诉你该喝阿萨伊果汁了，

or warn you of allergens in food

或者警告你食物中有过敏原

or many other truly helpful use cases.

或许多其他真正有用的使用场景。

To unlock more applications,

要解锁更多应用，

you will need to build a large error-corrected quantum computer.

你得打造一台经过误差校正的 大型量子计算机。

Here you see our road map.

你可以看到我们的路线图。

How to build a computer with a million physical qubits.

如何打造一台拥有一百万个 物理量子比特的计算机。

It consists of six milestones.

路线图包括六个里程碑，

and we achieved already the first two.

我们已经实现了前两个。

Prior to 2019,

2019 年之前，

nobody had shown a beyond classical computation on a quantum computer.

没有人在量子计算机上 展示过超越经典计算的能力。

We were the first to demonstrate it.

我们是第一个展示的人。

Our chip could perform a computation

我们的芯片可以执行

that the then-fastest supercomputer would have needed 10,000 years to do.

当时最快的超级计算机 需要一万年才能完成的计算。

But recently, we repeated this experiment.

但是最近，我们重复了这个实验。

And now, Frontier, today's top supercomputer,

当今顶级超级计算机 Frontier

would need one billion years to perform this computation.

需要十亿年才能完成这种计算。

This dramatic growth in compute power corroborates Neven's Law,

计算能力的急剧增长 证实了尼文定律，

which says that the power of quantum computers will grow

即量子计算机的能力 将以两倍指数的速度增长。

at a double exponential rate.

In 2023, we achieved the second milestone.

2023 年，我们达成了第二个里程碑。

We demonstrated again for the first time

我们首次证明量子误差校正 是一项可拓展的技术。

that quantum error correction is a scalable technology.

Error correction sounds boring, but it's crucial.

误差校正听起来很无聊， 但很关键。

Today, our two-qubit operations have an error rate of 1 in 1,000.

如今，我们的二量子比特运算的 误差率为千分之一。

That means that in every 1,000 steps or so,

意味着每进行 1000 步左右，

the quantum computer will crash.

量子计算机就会崩溃。

To improve this,

为了改良这一点，

we combine many physical qubits to a logical qubit

我们将许多物理量子比特 合并为一个逻辑量子比特，

to reduce the error rate to 1 in a billion or even less.

借此将误差率降低到了 十亿分之一甚至更低。

We are about halfway through our road map,

我们的路线图已接近一半，

and we are optimistic that we will complete it

我们乐观地认为 我们能在 2030 年以前完成。

before the end of this decade.

We have done analytical and numerical studies

我们已经进行了分析和数值研究，

to predict which algorithms will be impactful

预测哪些算法将对 如此大型的量子计算机产生影响。

on such a large quantum computer.

A class of applications we like and we call Feynman's killer app,

我们喜欢的一类应用程序， 我们称之为“费曼的杀手级应用”，

is the simulation of systems where quantum effects are important.

模拟了量子效应 对其很重要的系统。

This is relevant for designing more effective,

这与设计更有效、 更具针对性的药物有关。

more targeted medicines.

Specifically, we have worked with a pharmaceutical company

具体地说，我们已经与一家制药公司

on algorithms to describe cytochrome P450.

合作研究了 描述细胞色素 P450的算法。

This group of enzymes metabolizes about 75 percent of the drugs we take.

这组酶代谢了 我们服用的药物的大约 75％。

Or the design of lighter, faster-charging batteries

或者是设计更轻、 充电速度更快的电池，

that can hold a larger charge for electric cars

为电动汽车甚至电动飞机 提供更多的电量。

or even electric airplanes.

Or to hasten the design of fusion reactors to help with climate change,

或者加快聚变反应堆的设计， 帮助应对气候变化，

arguably humanity's most urgent challenge.

这可以说是人类最紧迫的挑战。

A recent result is a novel algorithm

近期成果是一种新颖的算法，

that delivers significant speed up for optimization.

可以显著提升优化速度。

This is a big deal

这很重要，

because optimization problems are ubiquitous

因为优化问题无处不在，

in engineering, finance or machine learning.

在工程、金融或者 机器学习领域都有。

A way to think about this result is in the future,

看待这个成果的一个角度是未来

when an AI will play chess or Go against the quantum AI,

当 AI 对战量子 AI 下国际象棋或围棋时，

the quantum AI will win.

量子 AI 将获胜。

This result shows that quantum computers

这个成果表明量子计算机

will become a must-have capability

将成为完成基础计算任务的必备能力。

to serve foundational computational tasks.

I'm also very interested in the intersection of physics

我对物理学和神经生物学的 交叉领域也很感兴趣。

and neurobiology.

Quantum information science

量子信息科学

may enable us to answer one of humanity's deepest questions:

可能会让我们能够回答 人类最深刻的问题之一：

What creates conscious experience?

是什么创造了意识经验？

An attractive conjecture is that consciousness

一个有趣的猜测是：意识

is how we experience the emergence

是我们经历那么一个经典世界

of a single classical world

out of the many the multiverse is composed of.

从若干多重宇宙中诞生的过程。

With academic collaborators,

我与学术合作者

I have started a program to experimentally test this conjecture

一起启动了一个项目， 对这一猜想进行实验测试，

using methods of quantum neurobiology.

使用了量子神经生物学的方法。

If our conjecture is correct,

如果我们的猜想是正确的，

this would allow us to expand human consciousness in space,

这将使我们能够在空间、时间 和复杂性上拓展人类意识。

time and complexity.

In conclusion,

总之，

we are making steady progress

我们正在取得稳步的进展，

towards building the world's first useful quantum computer

迈向打造世界上第一台 有用的量子计算机，

and applying its enormous power to important challenges.

并将其巨大力量应用于重要挑战。

A quantum computer will be a gift to future generations,

量子计算机将是 留给子孙后代的礼物，

giving them a new tool to solve problems that today are unsolvable.

为他们提供了解决 当今无法解决的问题的新工具。

Thank you.

谢谢。

(Applause)

（掌声）