Quantum computers aren't what you think — they're cooler | Hartmut Neven

[00:00:12] [SPEAKER_02]: Weve been promised a quantum computer for years.

[00:00:16] [SPEAKER_02]: The idea is that the next frontier of our technological evolution is a supercomputer

[00:00:21] [SPEAKER_02]: that can predict and synthesize information with speed and accuracy beyond what our day-to-day

[00:00:27] [SPEAKER_02]: computers can do.

[00:00:28] [SPEAKER_02]: Whenever I think about it, I envision a massive, floating device made up of bits and electric

[00:00:34] [SPEAKER_02]: currents poised to rule the world.

[00:00:37] [SPEAKER_02]: The reality isnt quite so sci-fi.

[00:00:39] [SPEAKER_02]: Quantum computers do exist, housed with big tech leaders like Google and IBM and inside

[00:00:45] [SPEAKER_02]: universities.

[00:00:47] [SPEAKER_02]: Theyre still in their infancy, but their existence is already fostering a new school of thought

[00:00:52] [SPEAKER_02]: on how to engage with quantum computers as they evolve.

[00:00:56] [SPEAKER_02]: This is TED Tech, a podcast from the TED Audio Collective.

[00:01:01] [SPEAKER_02]: Im your host, Sherelle Dorsey.

[00:01:04] [SPEAKER_02]: Today, we'll hear from scientist Hartmut Neven.

[00:01:07] [SPEAKER_02]: He is the vice president of engineering at Google and the founder and manager of the

[00:01:12] [SPEAKER_02]: Quantum Artificial Intelligence Lab.

[00:01:14] [SPEAKER_02]: He takes the TED stage to share how far this technology has come and what quantum computing

[00:01:20] [SPEAKER_02]: will one day look like for folks like you and me.

[00:01:23] [SPEAKER_02]: But before we dive into Hartmut's talk, a quick break to hear from our sponsors.

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[00:02:09] [SPEAKER_03]: Sometimes things in the world of technology are complicated and need careful explaining.

[00:02:15] [SPEAKER_03]: Sometimes they just need a little hard truth.

[00:02:18] [SPEAKER_00]: I don't think anyone is going to buy a banana with crypto at any point in the foreseeable

[00:02:22] [SPEAKER_00]: future.

[00:02:24] [SPEAKER_03]: Im Lizzie O'Leary, the host of Slate's What Next?

[00:02:26] [SPEAKER_03]: TBD, your clear-eyed guide to technology, power, and the future.

[00:02:30] [SPEAKER_03]: Friday and Sunday, wherever you get your podcasts.

[00:02:37] [SPEAKER_01]: I'm Hartmut.

[00:02:39] [SPEAKER_01]: I lead Google Quantum AI.

[00:02:42] [SPEAKER_01]: I have been working on quantum computing since 2012, and let me tell you why this is so intriguing.

[00:02:50] [SPEAKER_01]: Today's computers like your laptop or a server at a Google data center operate on the binary

[00:02:56] [SPEAKER_01]: logic of zeros and ones.

[00:02:58] [SPEAKER_01]: A quantum computer replaces the binary logic with the laws of quantum physics.

[00:03:03] [SPEAKER_01]: That gives it more powerful operations, allowing it to perform certain computations with way

[00:03:10] [SPEAKER_01]: fewer steps.

[00:03:11] [SPEAKER_01]: So where does this superpower come from?

[00:03:15] [SPEAKER_01]: Quantum computing is the first technology that takes the idea serious, that we live

[00:03:20] [SPEAKER_01]: in a multiverse.

[00:03:22] [SPEAKER_01]: It can be seen as farming out computations to parallel universes.

[00:03:27] [SPEAKER_01]: Let me explain.

[00:03:28] [SPEAKER_01]: In quantum physics, the key mathematical object to describe many worlds is called superposition.

[00:03:36] [SPEAKER_01]: You just need three bits to describe it.

[00:03:39] [SPEAKER_01]: Each coin is a two-state system, heads or tails, zero or one.

[00:03:45] [SPEAKER_01]: We look at a start state.

[00:03:47] [SPEAKER_01]: If I were to know which forces act on the system, then I can predict its trajectory

[00:03:55] [SPEAKER_01]: and future states.

[00:03:57] [SPEAKER_01]: This is how we reason in classical physics and also in everyday life.

[00:04:03] [SPEAKER_01]: But if you were to treat this as a quantum system, then it can branch into many configurations

[00:04:09] [SPEAKER_01]: simultaneously, and we have to keep track of all those trajectories, interfere them

[00:04:15] [SPEAKER_01]: to make an accurate prediction of what states we are going to see in the future.

[00:04:20] [SPEAKER_01]: So the equations of quantum mechanics tell us that at any time, any object, myself or

[00:04:30] [SPEAKER_01]: the world at large, exists in a superposition of many configurations.

[00:04:35] [SPEAKER_01]: Intriguingly, look around in this room.

[00:04:39] [SPEAKER_01]: We are forming a configuration, too.

[00:04:44] [SPEAKER_01]: And the equations of quantum physics would suggest that we sit in different arrangements

[00:04:50] [SPEAKER_01]: in different worlds.

[00:04:52] [SPEAKER_01]: This superpower can be applied to computation.

[00:04:55] [SPEAKER_01]: Picture a search task.

[00:04:57] [SPEAKER_01]: By envisioning a very tall closet with a million drawers, I place an item in one of the drawers.

[00:05:05] [SPEAKER_01]: How many drawers do you have to open to find the item?

[00:05:09] [SPEAKER_01]: In average, it will be half a million.

[00:05:11] [SPEAKER_01]: But if you had access to a quantum algorithm, it would only be a thousand steps to find the item.

[00:05:21] [SPEAKER_01]: How in the world can this be?

[00:05:23] [SPEAKER_01]: Indeed, it cannot be in a single world.

[00:05:26] [SPEAKER_01]: So here you see a good example of how quantum computing can attain an advantage by performing

[00:05:33] [SPEAKER_01]: computations in parallel worlds.

[00:05:35] [SPEAKER_01]: So what can you do with quantum computers today?

[00:05:39] [SPEAKER_01]: Today, we have prepared interesting quantum states and studied their properties.

[00:05:45] [SPEAKER_01]: This has led to dozens of publications in high-impact genres like nature or science.

[00:05:50] [SPEAKER_01]: Actually, I like to think of it as creating little pieces of magic.

[00:05:56] [SPEAKER_01]: For example, one state we prepared can be thought of as spawning a tiny traversable wormhole.

[00:06:03] [SPEAKER_01]: We can use it to learn about the physics of wormholes.

[00:06:06] [SPEAKER_01]: We can throw a qubit in and see how it reappears on the other side.

[00:06:11] [SPEAKER_01]: We made time crystals.

[00:06:13] [SPEAKER_01]: That's a cool word, isn't it?

[00:06:14] [SPEAKER_01]: Like who doesn't want to have a time crystal as an earring?

[00:06:19] [SPEAKER_01]: Time crystals have amazing physical properties.

[00:06:23] [SPEAKER_01]: They change periodically in time without ever exchanging energy with the environment.

[00:06:29] [SPEAKER_01]: They're the closest to a perpetual mobile that the laws of physics allow you to get.

[00:06:35] [SPEAKER_01]: Or a final example, non-abelian anions.

[00:06:39] [SPEAKER_01]: This is a mouse full.

[00:06:41] [SPEAKER_01]: But these are systems that change their overall properties

[00:06:45] [SPEAKER_01]: when exchanging two identical parts, something humans have never seen before.

[00:06:51] [SPEAKER_01]: Because envision a little house made of Lego bricks

[00:06:55] [SPEAKER_01]: and envision swapping two bricks that look identical.

[00:06:59] [SPEAKER_01]: In everyday life, you would not notice the difference,

[00:07:02] [SPEAKER_01]: but quantum physicists had predicted that systems can exist

[00:07:08] [SPEAKER_01]: that exchange or change their properties when you exchange two identical parts.

[00:07:15] [SPEAKER_01]: To date, nobody has performed a practical application

[00:07:20] [SPEAKER_01]: that can only be done on a quantum computer,

[00:07:23] [SPEAKER_01]: despite what you may have read in the press.

[00:07:26] [SPEAKER_01]: But today I'm excited to tell you

[00:07:28] [SPEAKER_01]: that we are completing the design of an algorithm

[00:07:32] [SPEAKER_01]: that may lead to first commercial applications.

[00:07:36] [SPEAKER_01]: This quantum algorithm performs signal processing

[00:07:39] [SPEAKER_01]: to enable new ways to detect and analyze molecules

[00:07:44] [SPEAKER_01]: using nuclear electronic spin spectroscopy.

[00:07:48] [SPEAKER_01]: In time, this may lead to exciting consumer applications.

[00:07:51] [SPEAKER_01]: Envision a device akin to an electronic nose in your phone or a smartwatch.

[00:07:59] [SPEAKER_01]: Wouldn't it be awesome if your phone could warn you

[00:08:02] [SPEAKER_01]: that you step into a room with dangerous viruses?

[00:08:05] [SPEAKER_01]: Or if your smartwatch could detect free radicals in your bloodstream

[00:08:10] [SPEAKER_01]: and tell you it's time to drink your acai juice

[00:08:13] [SPEAKER_01]: or warn you of allergens in food

[00:08:17] [SPEAKER_01]: or many other truly helpful use cases?

[00:08:21] [SPEAKER_01]: To unlock more applications,

[00:08:23] [SPEAKER_01]: we will need to build a large error-corrected quantum computer.

[00:08:28] [SPEAKER_01]: How to build a computer with a million physical qubits?

[00:08:32] [SPEAKER_01]: It consists of six milestones, and we achieved already the first two.

[00:08:38] [SPEAKER_01]: Prior to 2019,

[00:08:40] [SPEAKER_01]: nobody had shown a beyond classical computation on a quantum computer.

[00:08:45] [SPEAKER_01]: We were the first to demonstrate it.

[00:08:48] [SPEAKER_01]: Our chip could perform a computation

[00:08:50] [SPEAKER_01]: that the then fastest supercomputer would have needed 10,000 years to do.

[00:08:56] [SPEAKER_01]: But recently, we repeated this experiment,

[00:09:00] [SPEAKER_01]: and now, Frontier, today's top supercomputer,

[00:09:04] [SPEAKER_01]: would need one billion years to perform this computation.

[00:09:09] [SPEAKER_01]: This dramatic growth in compute power corroborates Nevin's law,

[00:09:14] [SPEAKER_01]: which says that the power of quantum computers

[00:09:17] [SPEAKER_01]: will grow at a double exponential rate.

[00:09:21] [SPEAKER_01]: In 2023, we achieved a second milestone.

[00:09:24] [SPEAKER_01]: We demonstrated again for the first time

[00:09:26] [SPEAKER_01]: that quantum error correction is a scalable technology.

[00:09:31] [SPEAKER_01]: Error correction sounds boring, but it's crucial.

[00:09:34] [SPEAKER_01]: Today, our two-qubit operations have an error rate of one in a thousand.

[00:09:39] [SPEAKER_01]: That means that in every thousand steps or so,

[00:09:44] [SPEAKER_01]: the quantum computer will crash.

[00:09:46] [SPEAKER_01]: To improve this, we combine many physical qubits to a logical qubit

[00:09:50] [SPEAKER_01]: to reduce the error rate to one in a billion or even less.

[00:09:56] [SPEAKER_01]: We are about halfway through our roadmap, and we're optimistic

[00:10:00] [SPEAKER_01]: that we will complete it before the end of this decade.

[00:10:04] [SPEAKER_01]: We have done analytical and numerical studies

[00:10:07] [SPEAKER_01]: to predict which algorithms will be impactful

[00:10:11] [SPEAKER_01]: on such a large quantum computer.

[00:10:14] [SPEAKER_01]: A class of applications we like and we call Feynman's killer app

[00:10:18] [SPEAKER_01]: is the simulation of systems where quantum effects are important.

[00:10:24] [SPEAKER_01]: This is relevant for designing more effective, more targeted medicines.

[00:10:30] [SPEAKER_01]: Specifically, we have worked with a pharmaceutical company

[00:10:32] [SPEAKER_01]: on algorithms to describe cytochrome P450.

[00:10:36] [SPEAKER_01]: This group of enzymes metabolizes about 75% of the drugs we take.

[00:10:41] [SPEAKER_01]: Or the design of lighter, faster-charging batteries

[00:10:46] [SPEAKER_01]: that can hold a larger charge for electric cars or even electric airplanes.

[00:10:51] [SPEAKER_01]: Or to hasten the design of fusion reactors

[00:10:55] [SPEAKER_01]: to help with climate change,

[00:10:58] [SPEAKER_01]: arguably humanity's most urgent challenge.

[00:11:03] [SPEAKER_01]: A recent result is a novel algorithm

[00:11:06] [SPEAKER_01]: that delivers significant speedup for optimization.

[00:11:10] [SPEAKER_01]: It's a big deal, because optimization problems are ubiquitous

[00:11:15] [SPEAKER_01]: in engineering, finance, or machine learning.

[00:11:19] [SPEAKER_01]: A way to think about this result is in the future,

[00:11:23] [SPEAKER_01]: when an AI will play chess or go against a quantum AI,

[00:11:27] [SPEAKER_01]: the quantum AI will win.

[00:11:29] [SPEAKER_01]: This result shows that quantum computers will become a must-have capability

[00:11:35] [SPEAKER_01]: to serve foundational computational tasks.

[00:11:39] [SPEAKER_01]: I'm also very interested in the intersection of physics and neurobiology.

[00:11:44] [SPEAKER_01]: Quantum information science may enable us

[00:11:47] [SPEAKER_01]: to answer one of humanity's deepest questions.

[00:11:51] [SPEAKER_01]: What creates conscious experience?

[00:11:54] [SPEAKER_01]: An attractive conjecture is that consciousness

[00:11:57] [SPEAKER_01]: is how we experience the emergence of a single classical world

[00:12:02] [SPEAKER_01]: out of the many the multiverse is composed of.

[00:12:05] [SPEAKER_01]: With academic collaborators,

[00:12:07] [SPEAKER_01]: I've started a program to experimentally test this conjecture

[00:12:11] [SPEAKER_01]: using methods of quantum neurobiology.

[00:12:15] [SPEAKER_01]: If our conjecture is correct,

[00:12:17] [SPEAKER_01]: this would allow us to expand human consciousness

[00:12:20] [SPEAKER_01]: in space, time, and complexity.

[00:12:23] [SPEAKER_01]: In conclusion, we are making steady progress

[00:12:26] [SPEAKER_01]: towards building the world's first useful quantum computer

[00:12:30] [SPEAKER_01]: and applying its enormous power to important challenges.

[00:12:34] [SPEAKER_01]: A quantum computer will be a gift to future generations,

[00:12:38] [SPEAKER_01]: giving them a new tool to solve problems that today are unsolvable.

[00:12:44] [SPEAKER_01]: Thank you.

[00:12:48] [SPEAKER_02]: That was Hottman Nevin at TED 2024.

[00:12:53] [SPEAKER_02]: And that's it for today.

[00:12:55] [SPEAKER_02]: TED Tech is part of the TED Audio Collective.

[00:12:57] [SPEAKER_02]: This episode was produced by Nina Byrd-Lawrence,

[00:13:00] [SPEAKER_02]: edited by Alejandro Salazar,

[00:13:02] [SPEAKER_02]: and fact-checked by Julia Dickerson.

[00:13:04] [SPEAKER_02]: Special thanks to Maria Eladius,

[00:13:06] [SPEAKER_02]: Farah DeGrunge,

[00:13:08] [SPEAKER_02]: Daniela Bellarezzo,

[00:13:10] [SPEAKER_02]: and Roxanne Hailesch.

[00:13:11] [SPEAKER_02]: I'm Sherelle Dorsey.

[00:13:13] [SPEAKER_02]: Thanks for listening in.