ELI5: Explain Like I'm 5

Slater determinant

Okay kiddo, so let's start with some basic ideas to help us understand Slater determinants. Do you know what an electron is?

Well, an electron is one of the little tiny pieces that make up atoms. Atoms are like the building blocks of everything around us, like the air we breathe and the water we drink.

Now, when we talk about electrons in atoms, we need to understand that electrons have something called "spin." It's like they can either spin up or spin down.

So, a Slater determinant is a special way of organizing electrons in an atom based on their spin. It's like a special arrangement of the electrons that helps us understand how they act and interact with each other.

Here's an example: Let's say we have two electrons in an atom. One electron is spinning up and the other is spinning down. We could write this arrangement as | ↑ ↓ ⟩. That just means the first electron is spinning up and the second electron is spinning down.

Now, if we wanted to write out all the possible ways of arranging the electrons in the atom, we would have to write down all the possible combinations of spin. That would look something like this:

| ↑ ↑ ⟩, | ↑ ↓ ⟩, | ↓ ↑ ⟩, | ↓ ↓ ⟩

But, we don't need to do that for a Slater determinant. Instead, we just write out one big expression that includes all the possible combinations of spin. It looks like this:

| 𝜓 ⟩ = 1/√2
(| ↑ ↓ ⟩ - | ↓ ↑ ⟩)

Don't worry about the math, just focus on what this means. It's like we're saying that the electrons in the atom can be arranged in lots of different ways, but we can simplify it by using this one expression that includes all the possible combinations of spin.

In summary, a Slater determinant is a special way of organizing electrons in an atom based on their spin. It provides us with a simplified expression that includes all the possible arrangements of spin, making it easier for scientists to understand how electrons behave in atoms.