From Scientific America:
Meet the Dropleton—a “Quantum Droplet” That Acts Like a Liquid
Physicists have created a new composite "quasiparticle" that could help probe the quantum mechanics of many particles working together.
Part particle, part liquid, a newly discovered "quasiparticle" has been dubbed a quantum droplet, or a dropleton. The dropleton is a collection of electrons and "holes" (places where electrons are missing) inside a semiconductor, and it has handy properties for studying quantum mechanics...
Scientific America: Meet the Dropleton—a “Quantum Droplet” That Acts Like a Liquid