: Researchers working with lasers and a gallium arsenide semiconductor created a new quasiparticle
that has liquid properties; they've dubbed it a “dropleton.” Energy pulses from the laser created electron–hole pairs, called excitons, in the gallium arsenide. At a certain threshold, the electrons and holes rearranged themselves and started flowing around one another like particles in a liquid. The new particles require at least four electron–hole pairs to be stable. More a mathematical tool than an actual particle, quasiparticles such as the dropleton may help scientists better understand the quantum mechanics involved in microscopic systems of large numbers of interacting particles.