Observation of quantum droplets in a strongly dipolar Bose gas
  Quantum fluctuations are the origin of genuine quantum many-body effects, and can be neglected in classical mean-field phenomena. Here we report on the observation of stable quantum droplets containing $\sim$ 800 atoms which are expected to collapse at the mean-field level due to the essentially attractive interaction. By systematic measurements on individual droplets we demonstrate quantitatively that quantum fluctuations stabilize them against the mean-field collapse. We observe in addition interference of several droplets indicating that this stable many-body state is phase coherent. 
Igor Ferrier-Barbut, Holger Kadau, Matthias Schmitt, Matthias Wenzel,   Tilman Pfau
cond-mat.quant-gas physics.atom-ph quant-ph