Light-based condensates, such as polariton lasers and Bose–Einstein condensates, show varying photon statistics, and their second-order coherence often deviates from the ideal value. Researchers in Päivi Törmä's Quantum Dynamics group at Aalto University, with Elliot Lloyd, measured the second-order coherence of polariton emission from a plasmonic lattice, separately for the ground state and the high-energy tail.
They observed a highly coherent state, with g(2)(0) − 1 below 10−4, and ultrafast dynamics faster than 1 THz. The process can be read as Bose–Einstein condensation with sub-50-femtosecond thermalisation, although the authors also suggest an alternative explanation: superradiance from emitters with vibrational degrees of freedom. The Aalto authors are Evgeny Mamonov, Lukas Freter, Sioneh Eyvazi and Päivi Törmä.
The preprint has not yet been peer reviewed.
Image: QMAT