Correction to: Nature Photonics https://doi.org/10.1038/s41566-021-00935-3, published online 20 December 2021.

In the print and PDF versions of this article initially published, there were composition errors in the fourth and final paragraphs. In the fourth paragraph, in two places, “J = 0” replaces “\(\sqrt {J = 0}\),” while in the final paragraph, the first of two instances of “\(\sqrt \tau\)” has been corrected to “τ.” The changes have been made to the PDF version of the article.