Originally posted by sonhouse http://www.sciencealert.com/time-crystals-might-exist-after-all-and-they-could-break-the-symmetry-of-space-and-time
What is the big deal about this? If there is some kind of movement at absolute zero, doesn't that mean there is energy there in spite of the absolute zero background?
The ground state does not necessarily have zero energy, but I don't think that they are talking about zero point energy. I had a look at the paper , the Hamiltonian they consider is not time-independent, but periodic H(t + T) = H(t). They show that the time that the system returns to its original state in is much longer than the driving frequency.