Quantum Gas Microscope Offers Glimpse of Quirky Ultracold Atoms
- The figure is an in-situ image of a thermal cloud where the individual atoms/sites can be clearly resolved over a large field of view of over 100 microns. We can lower the temperature of the cloud below the condensation point, to obtain 2D Bose-Einstein condensates with temperatures of ~5nK as seen below. In this image, the edges of the Thomas-Fermi profile are clearly seen, and the condensate is surrounded by some thermal atoms. Source: Markus Greiner, Harvard University
Physicists at Harvard University have created a quantum gas microscope that can be used to observe single atoms at temperatures so low the particles follow the rules of quantum mechanics, behaving in bizarre ways.
The work, published in Nature, represents the first time scientists have detected single atoms in a Bose-Hubbard optical lattice, a crystalline structure made solely of light. It's part of scientists' efforts to use ultracold quantum gases to understand and develop novel quantum materials.
"Ultracold atoms in optical lattices can be used as a model to help understand the physics behind superconductivity or quantum magnetism, for example," says senior author Markus Greiner, an assistant professor of physics at Harvard and an affiliate of the Harvard-MIT Center for Ultracold Atoms. "We expect that our technique, which bridges the gap between earlier microscopic and macroscopic approaches to the study of quantum systems, will help in quantum simulations of condensed matter systems, and also find applications in quantum information processing."
The quantum gas microscope developed by Greiner and his colleagues is a highresolution device capable of viewing single atoms - in this case, atoms of rubidium - occupying individual, closely spaced lattice sites. The rubidium atoms are cooled to just 5 billionths of a degree above absolute zero (-273 degrees Celsius).
In their paper, Bakr, Greiner, and colleagues present images of single rubidium atoms confined to an optical lattice created through projections of a laser-generated holographic pattern. The neighboring rubidium atoms are just 640 nanometers apart, allowing them to quickly tunnel their way through the lattice.
Bakr W.S., Gillen J.I., Peng A., Foelling S., Greiner M: Quantum Gas Microscope detecting single atoms in a Hubbard regime optical lattice. Nature 462 74-77 (2009)