The authors say they have a video of it levitating. This is way beyond error territory. This is either a deliberate hoax or a real discovery. The authors realize the significance of what they have. When you commit academic fraud, you go for something boring, or at least something difficult verify, like Hwang Woo-suk or Elizabeth Holmes, not simple and easily reproducible and altering the course of history.

Being published in a journal isn't what makes something true. That's just the scientific concensus process, but true facts have been true for all time. I can totally imagine someone who has made a discovery of this magnitude simply dumping it on arxiv for everyone to see. If it's true, we'll see levitation videos all over the world tomorrow. Even if you try to keep it secret or patent it, it's impossible for something this simple yet important. More noble to release it for the benefit of mankind. If it's a hoax, we'll know - not next year but next week - and their careers will be ruined.