Sometimes the question is more difficult than the answer. If we have an experiment we can reproduce that defies working theories then we have to propose new ones, but then we need a new experiment to prove that one. Actually, more like a whole regression test suite to check that everything we had explained with the defied theories can be predicted with the new theory.
How did they achieve absolute zero? How can you see this without light energy keeping it above zero?
What it looked like to me was three layers of refrigerators. (heat pumps)
There are also chemical reactions that ALWAYS absorb heat.
So, anyways, there was no light inside. I am unsure how they measured the vibration.
The Ivory Tower guys have done this a lot. An experiment disproves a long held theory, and they just shore up the theory.