Correction to: Nature Physics https://doi.org/10.1038/s41567-018-0224-7, published online 30 July 2018.

In the version of this Article originally published, in the Acknowledgements, for author B.A.B. the support from the Department of Energy should have been listed separately from the other acknowledgements. The sentence ‘B.A.B. acknowledges support for the analytic work from the Department of Energy (de-sc0016239), the Simons Investigator Award, the Packard Foundation, and the Schmidt Fund for Innovative Research.’ should have been ‘B.A.B. acknowledges support for the analytic work from the Department of Energy (de-sc0016239). B.A.B. also acknowledges support from a Simons Investigator Award, the Packard Foundation, and the Schmidt Fund for Innovative Research.’ The online versions of the article have been amended.