The Front Cover depicts two 13C spins that interact over nanometer-scale distances, thus allowing the number of spins in a cluster to be counted. The thermometer displays the cryogenic temperature used, and the 25 minutes on the clock represent the mixing time needed to enable the nuclei to influence each other over this distance range. The signal was enhanced by dynamic nuclear polarization to achieve this unprecedented mixing time needed to reach nanometer distances. More information can be found in the Research Article by L. B. Andreas and co-workers (DOI: 10.1002/cphc.202500585).
Varkey et al. (Thu,) studied this question.