Sure, a quantum transition takes time. But demonstrating that point experimentally is not new this year. In The Feynman Lectures on Physics, vol II, p. 35-4,

Sure, a quantum transition takes time. But demonstrating that point experimentally is not new this year. In The Feynman Lectures on Physics, vol II, p. 35-4, Feynman describes an experiment by I.I. Rabi. I think Rabi did the work in the 1940s. The reciprocal of the transition time is the 'Rabi Frequency'. http://mriquestions.com/who-discovered-nmr.html http://mriquestions.com/who-discovered-nmr.html https://www.aps.org/programs/outreach/history/historicsites/rabi.cfm https://www.aps.org/programs/outreach/history/historicsites/... Back to 2019, the dissertation abstract underlying the news story here doesn't appear to claim that this is the first experimental demonstration that quantum transitions take time. Which is probably good.