One-way quantum computer

Okay kiddo, have you heard of a computer that can solve problems really fast? That's a regular computer! But there's something even cooler called a quantum computer. It works differently and has the potential to solve problems that are impossible for regular computers.

Now, there are different types of quantum computers. Today we'll talk about the "one-way" quantum computer. That's like a big puzzle that needs to be solved step-by-step. You only get one chance to solve it, and once you start, there's no going back.

Imagine we're making a cake. We need to mix the ingredients in the right order and put it in the oven for the right amount of time. We can't mix everything together at once and change our mind halfway through. Once we start, we have to keep going until the cake is done.

A one-way quantum computer works similarly. Instead of mixing ingredients, we build something called a "quantum state". This quantum state is like a special set of Lego blocks that we put together in a certain way.

Once we've built the quantum state, we can "measure" it. That's like sticking a ruler into the cake to see if it's done. But not just any ruler will work – we need a special quantum ruler.

Now, here's where things get tricky. Once we measure the state, it disappears. It's like the cake disappearing after we measure it. So we can only get one answer for our question, and we have to be really careful when building the quantum state.

But if we do it right, we can get an answer to a really hard problem super fast! It's kind of like finishing the cake in record time because we followed the recipe exactly.

So, that's the ELI5 version of a one-way quantum computer. It's like a big puzzle that can solve super hard problems, but we can only solve it once and we have to be careful when building it.