What the f**k is quantum?

Bill Thompson, what the fuck is quantum? And I thought we could talk about, um, quantum...

If you could touch on the quantum physics and quantum theory to start off with, and then we'll get into quantum computing.

I've been saying for the last three years that, um, if you're terrified about AI, wait until the quantum computers come because it's gonna be a, an absolute game changer.

If you could just, um, give us a bit of an overvi- an overview background in terms of the theory first.

Um, absolutely.

I think quantum computing...

Well, so the first thing is quantum theory is our current best model for how the universe works.

Uh, and it's, it comes from an understanding that at a very, very small scale inside the atom, smaller than the atom, things behave very differently from how they look to us in the outside world.

Um, and the, the, at our scale, scale of being a human being, a whole load of the universe can be explained by what's called Newtonian physics.

Um, you have solid objects that bounce into each other.

You have things like the conservation of momentum, uh, conservation of angular momentum.

That there, there is a model of the world and the universe, but it's based around atoms as, as little hard balls that are stuck together.

They collide, they move.

Uh, gravity works as a force.

A whole load of ways of explaining and understanding the world.

Once you get down to the smaller scale, and in particularly more detailed measurements, it breaks down.

It doesn't seem to work properly.

Um, and this was first identified in, in odd things like, um, why is, um, why are very hot metals white, okay? Um, and it, and it turns out that it's, it's to do with the way that energy levels are distributed within electrons.

And when you start probing that in more detail, you start to realize that you need a whole different set of mathematics, a whole different explanation of how the universe works based around these properties at the quantum level, at the very small, you know, ten to the minus nine meters level.

And within that world, things do not have the properties you might expect.

For example, um, atomic particle, um, uh, subatomic particles, electrons, behave like they are waves moving through space, but also like they're solid particles, and they do that at the same time.

And they change, don't they? They change.

Well, well, they, they don't change.

They are bo- they are everything simultaneously.

A- and crucially, um, you f- you find that when you observe how particles interact, you can only explain them in mathematical and statistical terms, and it stops making sense to say they have a particular property at a particular time.