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

Summary

Hartmut Neven, head of Google Quantum AI, reveals the potential of quantum computing, which operates on quantum physics rather than binary logic, offering immense computational power. He explains the concept of superposition and its application in quantum search algorithms, demonstrating the technology's ability to perform tasks in parallel universes. Neven also discusses current applications in quantum state preparation, like time crystals and non-abelian anyons, and the future of quantum computing in medicine, optimization, and even understanding consciousness, highlighting Google's progress in quantum error correction and the roadmap to a million-qubit computer.

Takeaways

• 💻 Hartmut leads Google Quantum AI and has been working on quantum computing since 2012.
• 🔄 Quantum computers replace binary logic with quantum physics, allowing for more powerful operations.
• 🌐 Quantum computing is based on the concept of a multiverse, farming out computations to parallel universes.
• 🪙 Superposition in quantum physics is key to understanding many-worlds theory and quantum computing.
• 🧠 Quantum mechanics suggests that objects, including humans, exist in a superposition of many configurations.
• 🔍 Quantum algorithms can perform certain computations more efficiently than classical computers, like searching through a large database.
• 📚 Hartmut demonstrates using Cirq, a Python-based language, to program quantum computers, which is akin to reading sheet music.
• 💡 Quantum computers today are used to prepare interesting quantum states and study their properties, leading to high-impact publications.
• 🧪 Quantum computing may enable new applications like detecting and analyzing molecules using nuclear electronic spin spectroscopy.
• 🔬 Google's roadmap for quantum computing includes building a computer with a million physical qubits, with progress already made on the first two milestones.
• 🚀 Quantum computers could revolutionize fields like medicine, battery design, and fusion reactors by simulating systems where quantum effects are crucial.

Q & A

What is the fundamental difference between classical computers and quantum computers?

Classical computers operate on binary logic of zeros and ones, while quantum computers replace this with the laws of quantum physics, allowing for more powerful operations and the ability to perform certain computations with fewer steps.

How does the concept of a 'multiverse' relate to quantum computing?

Quantum computing is the first technology that takes the idea of a multiverse seriously, where computations can be seen as being 'farmed out' to parallel universes, leveraging the concept of superposition in quantum physics.

What is the significance of 'superposition' in quantum physics and how does it apply to quantum computing?

Superposition is a key mathematical object in quantum physics that allows an object to exist in a superposition of many configurations simultaneously. In quantum computing, this principle enables the simultaneous exploration of many computational paths, leading to potential computational advantages.

Can you explain the analogy of the 'tall closet with a million drawers' in the context of quantum computing?

This analogy is used to illustrate the efficiency of quantum algorithms in search tasks. On average, it would take half a million steps to find an item in a classical scenario, but with a quantum algorithm, it could be reduced to just 1,000 steps.

What is the practical use of quantum computers today, according to the script?

Today, quantum computers are used to prepare interesting quantum states and study their properties, leading to numerous publications. They have also been used to create phenomena like tiny traversable wormholes, time crystals, and non-abelian anyons, which are helping to advance our understanding of quantum physics.

What is the significance of quantum error correction in the development of quantum computers?

Quantum error correction is crucial for the development of quantum computers because it helps to reduce the error rate of qubit operations. By combining many physical qubits into a logical qubit, the error rate can be significantly lowered, making computations more reliable.

What is Hartmut Neven's Law and how does it relate to the growth of quantum computing power?

Neven's Law states that the power of quantum computers will grow at a double exponential rate. This law is used to illustrate the dramatic increase in computational power that has been observed in quantum computers, with recent demonstrations showing computations that would take today's top supercomputers billions of years to perform.

What are some of the potential commercial applications of quantum computing mentioned in the script?

The script mentions the potential for quantum computing to enable new ways to detect and analyze molecules using nuclear electronic spin spectroscopy, which could lead to consumer applications like an 'electronic nose' in phones or smartwatches that can detect dangerous viruses or allergens in food.

What is the current status of the roadmap for building a large, error-corrected quantum computer?

The roadmap consists of six milestones, and two have already been achieved. The first milestone demonstrated a computation beyond the capabilities of classical computers, and the second milestone proved that quantum error correction is scalable technology.

How does quantum computing intersect with the field of neurobiology and consciousness?

The script suggests that quantum information science may help answer deep questions about the nature of consciousness, such as how it emerges from the multiverse. There is a program to experimentally test the conjecture that consciousness is the experience of a single classical world emerging from the many worlds of the multiverse, using quantum neurobiology methods.

What are some of the long-term applications of quantum computing that are being explored?

Long-term applications being explored include the simulation of systems where quantum effects are important, which could aid in designing more effective medicines, lighter and faster-charging batteries for electric vehicles, and hastening the design of fusion reactors to combat climate change. Additionally, a novel algorithm for optimization could impact various fields such as engineering, finance, and machine learning.

Outlines

00:00

🚀 Introduction to Quantum Computing

Hartmut Neven, leader of Google Quantum AI, introduces quantum computing as a technology that operates beyond the binary logic of zeros and ones, harnessing the laws of quantum physics for more powerful operations. He explains that quantum computers can perform certain computations with fewer steps by utilizing the concept of superposition, where objects exist in multiple configurations simultaneously. This allows for parallel computation across different universes, exemplified by a search task in a quantum algorithm that drastically reduces the number of steps required compared to classical methods. Neven also demonstrates how to use a quantum computer in practice, showing a program in Cirq, a Python-based language, and how it is transmitted to Google's data center in Santa Barbara.

05:00

🌌 Quantum Computing Applications and Milestones

The speaker discusses the practical applications of quantum computing, highlighting the preparation of interesting quantum states and their study, which has led to numerous high-impact publications. He mentions the creation of time crystals, non-abelian anyons, and the potential for quantum computers to perform tasks that are currently impossible with classical computers. Neven then outlines Google's roadmap for building a large, error-corrected quantum computer, detailing six milestones and the progress made so far. He emphasizes the importance of quantum error correction in reducing error rates and the potential for quantum computers to revolutionize fields such as medicine, battery design, and fusion reactors. Additionally, he touches on the potential of quantum computing to solve optimization problems, which are prevalent in various industries.

10:01

🌟 Future Impact of Quantum Computing

In the final paragraph, Hartmut Neven envisions the future impact of quantum computing, suggesting that it will be a crucial tool for solving currently unsolvable problems. He discusses the potential of quantum computers to enhance human consciousness by exploring the intersection of physics and neurobiology, and how this could lead to new insights into the nature of consciousness. Neven also speculates on the implications of quantum computing for AI, predicting that a quantum AI would outperform a classical AI in games like chess or Go. He concludes by emphasizing the steady progress being made towards building a useful quantum computer and the immense potential it holds for future generations.

Keywords

💡Quantum Computing

Quantum computing is a revolutionary approach to processing information that uses the principles of quantum mechanics. Unlike classical computers that operate on bits with a state of 0 or 1, quantum computers use quantum bits, or qubits, which can exist in a superposition of states. This allows quantum computers to perform complex calculations much more efficiently than traditional computers. In the video, Hartmut Neven, the lead of Google Quantum AI, discusses the potential of quantum computing to solve problems that are currently unsolvable, highlighting its importance in the future of technology.

💡Binary Logic

Binary logic is the system of representing information using only two symbols, typically 0 and 1, which is the basis of classical computing. In the script, Neven contrasts binary logic with quantum logic, explaining that quantum computers replace this traditional system with the principles of quantum physics, thus enabling more powerful operations.

💡Superposition

In quantum physics, superposition is the concept where a quantum system can exist in multiple states simultaneously until it is measured. The script uses the example of a coin that can represent both heads and tails at once to illustrate superposition. This concept is fundamental to quantum computing, as it allows quantum computers to perform many calculations in parallel, significantly reducing the number of steps needed to solve complex problems.

💡Multiverse

The multiverse is a hypothetical group of multiple universes, including the one we inhabit. In the context of quantum computing, the script suggests that quantum computers can be seen as 'farming out computations to parallel universes,' leveraging the concept of superposition to perform tasks more efficiently. This is a metaphorical way of explaining how quantum computers can explore many possible outcomes simultaneously.

💡Quantum Algorithm

A quantum algorithm is a set of instructions that leverages the unique properties of quantum mechanics to solve problems. In the video, Neven describes how quantum algorithms, such as the one for quantum search, can find an item in a large dataset much faster than classical algorithms. This demonstrates the potential of quantum computing to outperform classical computing in specific tasks.

💡Cirq

Cirq is a Python library developed by Google for writing, manipulating, and optimizing quantum circuits and then running them against quantum computers and simulators. The script mentions Cirq as an example of a programming language used to express quantum algorithms, comparing the structure of a quantum program to sheet music, with lines representing qubits and boxes representing operations.

💡Qubits

Qubits, short for quantum bits, are the basic units of quantum information. Unlike classical bits, qubits can exist in a superposition of states, which is crucial for the computational power of quantum computers. The script discusses how operations on qubits are translated into waveforms and electrical pulses that control the quantum computer's behavior.

💡Quantum Error Correction

Quantum error correction is a set of techniques used to protect quantum information from errors due to decoherence and other quantum noise. In the script, Neven explains the importance of error correction for making quantum computing practical, as it reduces the error rate from 1 in 1,000 to 1 in a billion or less, which is essential for performing reliable computations.

💡Neven's Law

Neven's Law, as mentioned in the script, is a concept that states the power of quantum computers will grow at a double exponential rate. This law, attributed to Hartmut Neven, illustrates the rapid advancement in quantum computing power and its potential to vastly outperform classical computers in the future.

💡Quantum Simulation

Quantum simulation refers to the use of quantum computers to model quantum systems, which is something classical computers struggle to do efficiently. In the video, Neven discusses the potential of quantum simulation for designing more effective medicines, understanding enzyme behavior, and aiding in the development of new materials and technologies.

💡Consciousness

Consciousness, as touched upon in the script, is the state of being aware of and able to think and perceive one's surroundings, thoughts, and emotions. Neven suggests an intriguing intersection between quantum information science and neurobiology, hypothesizing that consciousness may be linked to the emergence of a single classical world from a multiverse. This concept is explored in the context of expanding human consciousness and understanding its origins.

Highlights

Hartmut leads Google Quantum AI and has been working on quantum computing since 2012.

Quantum computers replace binary logic with quantum physics, enabling more powerful operations.

Quantum computing is the first technology to seriously consider the idea of a multiverse.

Quantum computers can perform computations in parallel universes, giving them a superpower.

Superposition in quantum physics allows objects to exist in many configurations simultaneously.

Quantum computing can apply the concept of superposition to perform computations more efficiently.

An example of quantum advantage is finding an item in a million-drawer closet in only 1,000 steps.

Quantum computers can be programmed using Cirq, a Python-based language.

Google's most powerful quantum computers now have over 100 qubits.

Quantum algorithms can be used to prepare interesting quantum states and study their properties.

Quantum computing has led to the creation of tiny traversable wormholes for studying physics.

Time crystals are a unique quantum state that changes periodically without exchanging energy.

Non-abelian anyons are quantum systems that change properties when exchanging identical parts.

Google is completing the design of a quantum algorithm for signal processing in molecular detection.

Quantum computers could enable devices like an electronic nose in phones for detecting viruses or allergens.

Google's roadmap includes building a computer with a million physical qubits.

Quantum error correction is crucial for reducing error rates in quantum computing.

Quantum computers could simulate systems where quantum effects are important, aiding in drug design and battery technology.

A novel quantum algorithm has been developed for significant speed up in optimization problems.

Quantum information science may help answer questions about the nature of consciousness.

Google is making steady progress towards building a useful quantum computer for solving unsolvable problems.

Transcripts

I'm Hartmut, I lead Google Quantum AI.

I have been working on quantum computing since 2012.

And let me tell you why this is so intriguing.

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

operate on the binary logic of zeros and ones.

A quantum computer like this one replaces the binary logic

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

allowing it to perform certain computations with way fewer steps.

So where does this superpower come from?

Quantum computing is the first technology

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

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

Let me explain.

In quantum physics,

the key mathematical object

to describe many worlds is called superposition.

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

You just need three bits to describe it.

Each coin is a two-state system.

Heads or tails,

zero or one.

We look at a start state.

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

then I can predict its trajectory and future states.

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

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

then it can branch into many configurations simultaneously.

And we have to keep track of all those trajectories,

interfere them to make an accurate prediction

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

So the equations of quantum mechanics

tell us that at any time, any object,

myself or the world at large,

exists in a superposition of many configurations.

Intriguingly, look around in this room.

We are forming a configuration too.

And the equations of quantum physics would suggest

that we sit in different arrangements in different worlds.

This superpower can be applied to computation.

Picture a search task.

By envisioning a very tall closet with a million drawers,

I place an item in one of the drawers.

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

In average it will be half a million,

but if you had access to a quantum algorithm,

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

How in the world can this be?

Indeed, it cannot be in a single world.

So here you see a good example

of how quantum computing can attain an advantage

by performing computations in parallel worlds.

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

So here you see a program in Cirq,

or Python-based programming language to express quantum algorithms.

It looks like sheet music.

Each line represents a qubit,

and each box represents an operation.

When I hit return,

then it gets transmitted to our data center

in Santa Barbara.

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

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

There, the operations get translated into waveforms,

electrical pulses that control the qubits.

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

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

For the programmers among you,

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

by only doing a single call to the database.

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

So what can you do with quantum computers today?

We have prepared interesting quantum states

and studied their properties.

This has led to dozens of publications

in high-impact journals like Nature or Science.

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

For example, one state we prepared

can be thought of as spawning a tiny traversable wormhole.

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

We can throw a qubit in

and see how it reappears on the other side.

We made time crystals.

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

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

Time crystals have amazing physical properties.

They change periodically in time without ever exchanging energy

with the environment.

That's the closest to a perpetual mobile

that the laws of physics allow you to get.

Or a final example, non-abelian anyons.

This is a mouthful,

but these are systems that change the overall properties

when exchanging two identical parts,

something humans have never seen before.

Because envision a little house made of Lego bricks

and envision swapping two bricks that look identical.

In everyday life, you would not notice a difference,

but quantum physicists had predicted that systems can exist,

that exchange or change their properties

when you exchange two identical parts.

To date, nobody has performed

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

Despite what you may have read in the press.

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

of an algorithm that may lead to first commercial applications.

This quantum algorithm performs signal processing

to enable new ways to detect and analyze molecules

using nuclear electronic spin spectroscopy.

In time, this may lead to exciting consumer applications.

Envision a device akin to an electronic nose

in your phone or smart watch.

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

that you step into a room with dangerous viruses?

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

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

or warn you of allergens in food

or many other truly helpful use cases.

To unlock more applications,

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

Here you see our road map.

How to build a computer with a million physical qubits.

It consists of six milestones.

and we achieved already the first two.

Prior to 2019,

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

We were the first to demonstrate it.

Our chip could perform a computation

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

But recently, we repeated this experiment.

And now, Frontier, today's top supercomputer,

would need one billion years to perform this computation.

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

which says that the power of quantum computers will grow

at a double exponential rate.

In 2023, we achieved the second milestone.

We demonstrated again for the first time

that quantum error correction is a scalable technology.

Error correction sounds boring, but it's crucial.

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

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

the quantum computer will crash.

To improve this,

we combine many physical qubits to a logical qubit

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

We are about halfway through our road map,

and we are optimistic that we will complete it

before the end of this decade.

We have done analytical and numerical studies

to predict which algorithms will be impactful

on such a large quantum computer.

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

is the simulation of systems where quantum effects are important.

This is relevant for designing more effective,

more targeted medicines.

Specifically, we have worked with a pharmaceutical company

on algorithms to describe cytochrome P450.

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

Or the design of lighter, faster-charging batteries

that can hold a larger charge for electric cars

or even electric airplanes.

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

arguably humanity's most urgent challenge.

A recent result is a novel algorithm

that delivers significant speed up for optimization.

This is a big deal

because optimization problems are ubiquitous

in engineering, finance or machine learning.

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

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

the quantum AI will win.

This result shows that quantum computers

will become a must-have capability

to serve foundational computational tasks.

I'm also very interested in the intersection of physics

and neurobiology.

Quantum information science

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

What creates conscious experience?

An attractive conjecture is that consciousness

is how we experience the emergence

of a single classical world

out of the many the multiverse is composed of.

With academic collaborators,

I have started a program to experimentally test this conjecture

using methods of quantum neurobiology.

If our conjecture is correct,

this would allow us to expand human consciousness in space,

time and complexity.

In conclusion,

we are making steady progress

towards building the world's first useful quantum computer

and applying its enormous power to important challenges.

A quantum computer will be a gift to future generations,

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

Thank you.

(Applause)