A non-perturbative no-go theorem for photon condensation in approximate models G. M. Andolina, F. M. D. Pellegrino, A. Mercurio, O. Di Stefano, M. Polini and S. Savasta Eur. Phys. J. Plus, 137 12 (2022) 1348 Published online: 16 December 2022 DOI: 10.1140/epjp/s13360-022-03571-0