This Article contains a typographical error in the sentence preceding Eq. 4. This sentence should read, ‘Under the secular approximation and working in the limit , the dynamical equation for the phonon occupancy can be simplified to’; that is, with a much-less-than symbol rather than a much-greater-than symbol.

There is a further error in Fig 4. The label on the upper state of the right-most transition in Fig. 4b should be “” not “”.