At its heart, quantum entanglement is nothing more or less than a correlation between two apparently separate quantum objects.

Superposition is the ability of quantum objects to be in two places at once.

It arises in quantum mechanics simply due to the matter wave nature of all quantum objects.

- that no two quantum objects can share the same state?

Quantum entanglement describes the relationship and correlation between two apparently separate quantum objects.

"Why should an assembly of a trillion weird little quantum objects behave any less mysteriously than its components?"

No seriously, it turns out that if you get it right, a fridge made from just a single quantum object, like an atom, is possible.

So, there you go: the smallest fridge consists of one quantum object with three states.

I have used the example of atoms, but really, any quantum object will do.

But these quantum objects need to have carefully matched energy states so that unidirectional energy flow is favored.