ELI5: Explain Like I'm 5

Schrödinger functional

Okay kiddo, imagine you have a box filled with something we can't see, like candy. But this candy is really special, and can do strange things that normal candy can't. We want to figure out what's happening inside the box.

Now, imagine we have a way to control the candy in the box. We can change the temperature, or add more candy, or take some out. And every time we do something like that, we can measure how the candy reacts.

That's kind of what a Schrödinger functional is. It's a way for scientists to control and measure something that's hidden, like the candy in the box. But instead of candy, they're usually looking at something really tiny, like the particles that make up atoms.

They start with a special equation, called the Schrödinger equation, which tells them how those particles behave. Then they "treat" the equation like a recipe, and add in some new things to control the particles and measure how they respond. They may change the temperature, or how much energy the particles have, or even the shape of the container the particles are in.

Then, they watch what happens as the particles interact with each other and respond to the changes. They might be able to learn new things about how the particles behave, or even discover something completely new.

So, that's what a Schrödinger functional is – it's a way for scientists to "play" with the Schrödinger equation in a controlled way, to learn more about really tiny things that we can't see.