There are a few key differences in our work. First, it's a very different system; the prior experiments were done using trapped ions, and "defects" (nitrogen-vacancy centers) in diamond, while our system used nuclear spins. The more important difference is that our system is very ordered, since it took place on an actual crystal lattice with a high degree of symmetry (this matters because some theories proposed the need for this disorder to observe the effect -- the trapped ion experiment even purposely included disorder). This is the reason for our use of the word "ordered" in the title of the paper.
Other differences include our further work to clarify the phemomenon, including the creation of "echoes" to explore the coherence of the system (see my other comments) among other new contributions about the parameter space and behavior of the effect. Finally, it's just surprising to have observed this effect across so many systems which are all so different from each other (very different Hamiltonians).
Other differences include our further work to clarify the phemomenon, including the creation of "echoes" to explore the coherence of the system (see my other comments) among other new contributions about the parameter space and behavior of the effect. Finally, it's just surprising to have observed this effect across so many systems which are all so different from each other (very different Hamiltonians).