The Truth About Quantum Computers | What the Physics?!

0:00 - It's bold.

0:01 It's weird.

0:03 And it could change pretty much everything.

0:06 I'm talking about quantum computing.

0:08 For decades, the tech world has been trying

0:11 and kinda failing

0:12 to figure out how to actually make quantum computers

0:14 live up to the hype.

0:16 Until early 2025

0:19 when Microsoft announced they'd cracked it.

0:21 They say the key is hiding in

0:23 some of the strangest particles in the universe,

0:27 majoranas.

0:28 Tiny, ghostlike quantum entities

0:31 that are their own antiparticles.

0:34 If they're right, Microsoft is closer than ever

0:36 to a massive breakthrough.

0:38 But what makes them so confident now?

0:39 And why has quantum computing been so hard to get right?

0:45 To understand quantum computing,

0:46 first we need to understand what quantum computers are,

0:50 exactly what problem Microsoft was trying to solve,

0:53 and why this is all such a big deal.

0:55 And stick with me,

0:56 because we're going quantum here,

0:58 and any time we do that, things can get a little spooky.

1:03 See, quantum computing is a field

1:05 within computer science and engineering

1:07 that pulls from quantum mechanics,

1:09 the physics of matter and energy

1:11 at the atomic and subatomic level.

1:14 One of the strange properties of physics

1:16 at the quantum scale is superposition,

1:19 the idea that particles can exist

1:20 in two or more states at once,

1:23 like a top spinning clockwise and counterclockwise

1:26 at the same time.

1:28 I told you, spooky.

1:30 The idea is to use these strange laws of quantum mechanics

1:33 to build computers that can quickly solve

1:35 really complex problems.

1:37 Take data encryption,

1:39 which is used to keep information secure.

1:41 Right now, online data encryption uses a lot of math

1:45 to send information that can easily be understood

1:47 by the intended recipient,

1:49 but not by anyone else.

1:51 At the most fundamental level,

1:53 online encryption relies on multiplying

1:55 two large prime numbers together,

1:57 making a new, incredibly large number.

2:00 Without any additional information,

2:02 it can take a lot of computing power

2:04 and a really long time

2:05 to figure out those first two prime numbers.

2:08 Which makes this method pretty secure

2:10 for traditional computers.

2:11 See, from your personal laptop

2:13 to the world's biggest supercomputer,

2:15 traditional computers are based on classical physics,

2:18 and they use electrical impulses

2:20 that code information in a binary way,

2:22 using either 0 or 1, which are bits.

2:26 But the limits of binary

2:28 and possibilities of problems like overheating

2:31 mean there will be some problems

2:33 traditional computers simply don't have enough power

2:36 or enough time to solve.

2:38 Quantum computers, on the other hand,

2:40 compute in a whole different way.

2:42 Instead of bits they use quantum bits called qubits,

2:46 which can be zero or one or both

2:49 or anything in between.

2:51 Because qubits can be more things at once,

2:53 they can find and compare possible solutions

2:55 to some problems

2:57 much more quickly than a traditional computer.

3:00 But we don't fully have quantum computers yet

3:02 because qubits are really sensitive

3:04 to their surrounding environment,

3:06 making them susceptible to decoherence.

3:09 Basically, the qubits can lose their quantum state.

3:12 They become damaged, losing information

3:15 and making errors.

3:16 The more qubits you add to a chip,

3:18 the more powerful the computer will be,

3:21 but the more likely it is

3:22 for the qubits to lose their state and make errors.

3:26 So that's the problem the tech world

3:27 has been grappling with for decades.

3:30 How to avoid decoherence

3:31 and make a quantum computer that's reliable

3:34 and practical at scale.

3:36 And tech companies have tried a few different methods

3:38 for solving this problem.

3:40 IBM and Google have both built quantum computers

3:42 using superconducting materials to create qubits,

3:45 and the Canadian company Xanadu

3:47 has made a quantum computer that uses photons,

3:50 particles of light, to create qubits.

3:53 But neither of these methods

3:54 is completely reliable or scalable.

3:57 That's because superconducting quantum computers

4:00 need to be kept super cold,

4:02 and photons are really easy to lose

4:04 and really hard to manipulate.

4:07 So Microsoft is working on another approach,

4:09 topological qubits,

4:11 which use special particles called Majorana fermions.

4:15 In particle physics,

4:16 the idea is that somewhere out there,

4:18 most particles should have a corresponding antiparticle,

4:22 which has the same mass,

4:23 but with an opposite charge.

4:25 And if a particle meets its antiparticle,

4:28 boom, it's over for them both.

4:30 But Majoranas are particles

4:32 that are also their own antiparticles,

4:34 meaning if they met, they might annihilate each other,

4:38 or they might not.

4:39 They can exist in two states.

4:41 In theory, anyway.

4:42 No one's ever been able to actually use Majoranas.

4:46 Until now.

4:47 Microsoft claimed not only had they observed Majoranas,

4:50 they also figured out how to control them.

4:52 And they said they'd be able to use them

4:54 to build reliable qubits

4:56 that would be able to hold up

4:57 in ways that other qubits can't.

4:59 This breakthrough would provide a much faster pathway

5:01 to quantum computing at a much larger scale

5:04 than anyone else has been able to achieve.

5:07 Microsoft was faced with an avalanche of skepticism.

5:10 And as of filming,

5:11 the data hasn't firmly established everything they claimed.

5:15 But some are optimistic

5:16 that Microsoft can improve its chip

5:18 and provide the breakthrough

5:20 the industry has been waiting for.

5:22 If they do, the whole world will change fast

5:25 as we gain the ability to solve all kinds of problems

5:28 we can't currently fully explore.

5:30 For example, we might be able to create

5:32 computer simulations of our world,

5:34 down to the molecular level.

5:36 That would open the door for incredible breakthroughs

5:38 in chemistry and medicine.

5:40 Or we could develop new battery technology,

5:43 which could be key for mitigating climate change.

5:46 But quantum computing could also open up new problems.

5:49 Remember how it could take traditional computers

5:51 a really long time to access encrypted data?

5:54 Quantum computers would have access to

5:56 all of our private information within minutes.

5:59 That means whoever cracks quantum computing

6:01 on a large scale first

6:03 could get really powerful, really fast.

6:06 The field of quantum computing

6:08 holds fascinating and exciting possibilities

6:10 for science and technology,

6:13 but it also opens new questions for all of us to consider.

6:17 Can we build these powerful new machines?

6:19 And if we can, what will it look like

6:22 to wield that kind of technological power responsibly?

6:28 (gentle music)