Question about "time crystals'':

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?

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 article does a very poor job of explaining it. I suspect the writer didn't know what it was all about either.

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 [1], 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.

[1] https://arxiv.org/pdf/1603.08001v4.pdf