The Quantum Internet

SPEAKER_1 (0:00)

This episode is brought to you by Accenture. When you're advertising operations fall out of sync, everything else follows. Spotify and Accenture are working together to reinvent the rhythm of ad sales. Using automation, analytics, and smarter workflows to simplify campaign delivery and access better data across the business. The result? Less time spent on operations, more time connecting brands with the moments and fandoms that matter most. Learn more at accenture.com/spotify.

SPEAKER_2 (0:30)

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Matt O'Dowd (1:00)

When we finally have a quantum internet, you'll be able to simultaneously like and dislike this video. But we don't yet. So I hope you like it.

The world is widely regarded as being well and truly into the digital age, also called the information age. No longer are economies and industries solely characterized by the physical goods they produce. And in fact, some of the largest companies in the world produce no physical goods at all. Digital information is a commodity in its own right. As discussed in our previous episode, this worldwide digital economy is fundamentally reliant on certain cryptographic processes. Currently these processes work in the realm of classical cryptography. But one day soon this may not be enough. And so quantum cryptographic methods and algorithms are being developed. However, it's one thing to design a protocol. It's something else entirely to build a system to support it. To understand what needs to be done, we need to get to the foundations of quantum mechanics. We need to talk about quantum information theory. First, plain old non-quantum information theory. The study of the creation, storage and transmission of information, typically in the form of classical bits. Ones and zeros.

Claude Shannon started it all with his 1948 paper A Mathematical Theory of Communication, which quantified the rate of digital information that can be transferred without error, given the amount of noise in a communication channel.

Information theory has since blossomed into a full science, ultimately connecting the concept of information and certain fundamentals of physics, such as entropy and also quantum theory. Quantum information theory parallels classical information theory, but instead of using classical bits, it deals in bits of quantum information. Cubits Cubits enjoy all of the weirdness of quantum mechanics. They can be in a superposition of many states at once, defined only when they're measured. Two cubits can be entangled with each other, so both of their states are determined when one is measured. They can even be teleported.

Cubits are also subject to some fundamental restrictions, which I'll get to. Those restrictions, on top of all of that weirdness, define the challenge of transmitting and storing quantum information. But first, a reminder of why we want to muck around with quantum info in the first place. First, there's the whole quantum computer thing. Now in those, the ability for a qubit to hold many simultaneous states can lead to massive speed ups in certain types of computing.

And partly motivated by the cryptographic cracking power of the quantum computer, we also want to think about a quantum internet. In fact, we already did. In our episode on quantum key distribution, we talked about two schemes for sharing cryptographic keys.

SPEAKER_1 (4:00)

This episode is brought to you by Accenture. When your advertising operations fall out of sync, everything else follows. Spotify and Accenture are working together to reinvent the rhythm of ad sales.

Using automation, analytics and smarter workflows to simplify campaign delivery and access better data across the business. The result? Less time spent on operations, more time connecting brands with the moments and fandoms that matter most. Learn more at accenture.com/spotify.

SPEAKER_2 (4:30)

You know those tiny back-to-school emergencies that somehow become your problem? That's why I love Uber Eats. You can order school supplies, snacks, and lunchbox essentials for $5 or less. So when your kid casually drops, I don't like peanut butter anymore. Or I need five green highlighters for a project due tomorrow. Uber Eats has you covered. Get everything you need for back-to-school today from your favorite brands like Albion Staples on Uber Eats. Order now.

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