Single ions — extremely cool
One of the fundamental questions in the search for the “theory of everything” is whether fundamental constants possibly vary. To prove this in the case of the fine-structure constant, for instance, we have to measure the spectral lines of atoms more accurately. Quantum logic spectroscopy provides such a method. Physicists from the QUEST Institute at the Physikalisch-Technische Bundesanstalt (PTB) and from the Leibniz University of Hanover have come one decisive step closer to this goal.