Controlling photon–phonon entanglement in a three-mode optomechanical system Abderrahim Lakhfif, Jamal El Qars and Mostafa Nassik Eur. Phys. J. D, 75 6 (2021) 189 Published online: 28 June 2021 DOI: 10.1140/epjd/s10053-021-00205-5