"In superconductors, the electrons act like two reticent people at a dance party. At first, neither person wants to dance with the other. But then the DJ plays a song that both people like, allowing them to relax. They notice one another enjoying the song and become attracted from afar – they have paired but have not yet become coherent.

Then the DJ plays a new song, one that both people absolutely love. Suddenly, the two people pair and start to dance. Soon everyone at the dance party follows their lead: They all come together and start dancing to the same new tune. At this point, the party becomes coherent; it is in a superconducting state.

In the new study, the researchers observed electrons in a middle stage, where the electrons had locked eyes, but were not getting up to dance."

This is an awesome ELI5.