Many-body study of the photoisomerization of the minimal model of the retinal protonated Schiff base

► We theoretically studied the photoisomerization of the PSBMM by GW-BSE methods. ► We found that the photoisomerization follows the two-state model. ► This description agrees with previous CASPT2 and Quantum Montecarlo results. ► All TDDFT calculations predict an energy barrier along the isomerization path. ► Using hybrid exchange-correlation functionals in TDDFT reduces this gap.