Probing the Superfluid–to–Mott-Insulator Transition at the Single-Atom Level

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Science  17 Jun 2010:
DOI: 10.1126/science.1192368


Quantum gases in optical lattices offer an opportunity to experimentally realize and explore condensed-matter models in a clean, tunable system. We investigate the Bose-Hubbard model on a microscopic level using single atom–single lattice site imaging; our technique enables space- and time-resolved characterization of the number statistics across the superfluid–Mott insulator quantum phase transition. Site-resolved probing of fluctuations provides us with a sensitive local thermometer, allows us to identify microscopic heterostructures of low-entropy Mott domains, and enables us to measure local quantum dynamics, revealing surprisingly fast transition time scales. Our results may serve as a benchmark for theoretical studies of quantum dynamics and may guide the engineering of low-entropy phases in a lattice.