“Coherent and ultrafast laser excitation creates an exotic matter phase with spatially overlapping electronic wave-functions under nanometric control in an artificial micro-crystal of ultracold atoms. This exotic metal-like quantum gas under exquisite control and long-lived, decaying in nanoseconds, opens up a completely new regime of many-body physics for simulating ultrafast many-body electron dynamics dominated by Coulomb interactions.
Electronic properties of condensed matter are often determined by an intricate competition between kinetic energy that aims to overlap and delocalize electronic wave functions across the crystal lattice, and localizing electron-electron interactions. In contrast, the gaseous phase is characterized by valence electrons tightly localized around the ionic atom cores in discrete quantum states with well-defined energies. As an exotic hybrid of both situations, one may wonder which state of matter is created when a gas of isolated atoms is suddenly excited to a state where electronic wave functions spatially overlap like in a solid? Such an exotic phase of matter, however, has so far been impossible to be created in principle. Here, Professor Kenji Ohmori, Institute for Molecular Science, National Institutes of Natural Sciences in Japan, and his coworkers have realized such an exotic hybrid with overlapping high-lying electronic (Rydberg1)) wave-functions created coherently within only 10 picoseconds (pico = one trillionth) by ultrafast laser excitation in an artificial micro-crystal of ultracold atoms (see Fig. 1). The degree of spatial overlap is actively tuned with nearly 50 nanometer precision and accuracy (nano = one billionth). This exotic metal-like quantum gas under exquisite control and long-lived, decaying in nanoseconds, opens up a completely new regime of many-body physics for simulating ultrafast many-body electron dynamics dominated by Coulomb interactions”