Polaritons are enthralling quasi-particles, result of a strong coupling between photons in microcavities and excitons in semiconductors. This successful marriage of light and matter has led to many intriguing and fascinating effects, object of innumerable studies in the past 20 years. In this talk we will see some of the interesting phenomena of such quasi-particles featuring condensation, ultrafast motion, complex fluid dynamics and non-linear effects. In particular we will focus on both, their quantum macroscopic behavior–including long range order, superfluidity, quantized vortices and X-waves formation [1-3]–as well as truly quantum phenomena (entanglement) involving single particles under linear and nonlinear regime .
 G. Lerario, A. Fieramosca, et al., Room-temperature superfluidity in a polariton condensate, Nat. Phys., doi:10.1038/nphys4147 (2017).
 D. Caputo, D. Ballarini, et al. Topological order and equilibrium in a condensate of exciton-polaritons, arXiv:1610.05737 )2016
 A. Gianfrate, L. Dominici, et al., “Exciton Polariton X-waves”, arXiv:1703.02313 (2017).
 A. Cuevas, B. Silva, et al., Entangling a polariton with one photon: effect of interactions at the single-particle level, arXiv:1609.01244 (2016).