Quantum degenerate Fermi and Bose gases in microscopic traps

量子力学的含义继续挑战我们对世界的理解。2001年，诺贝尔物理学奖授予了首次在稀释气体中观察到玻色-爱因斯坦凝聚体（BEC）的科学家。BEC实验使用激光来冷却和捕获中性原子气体。然后，激光冷却的原子被装入一个磁阱，在那里它们被压缩并进一步冷却。最后，在实验室可达到的最低温度下，气体会发生量子简并。超冷原子实验激发了科学家和非科学家的想象力，因为我们可以用一台普通的相机看到量子世界。简并气体可以作为高温超导体等技术相关材料的模拟器。最终，我们从冷原子中学到的多体物理学可能会解决这些量子材料的开放性问题。在我们的实验室里，我们用一个微小的“芯片”陷阱捕获了两个物种（铷87，一种玻色子，和钾40，一种费米子）。我们使用玻色气体作为量子“冰块”来冷却费米气体。在芯片陷阱中产生的强约束导致交感冷却速率比费米气体的典型实验快大约十倍。我们还表明，同样的强约束导致了玻色-爱因斯坦凝聚的最高效率蒸发冷却路径之一。在接下来的五年里，我们计划研究这些量子气体的多体物理，包括冷费米子的光散射特性，非谐波陷阱，以及玻色-费米混合物的物理。

The implications of quantum mechanics continue to challenge our understanding of the world. In 2001, the Nobel Prize in Physics was awarded in recognition of the first observation of a Bose-Einstein condensate (BEC) in a dilute gas. A BEC experiment uses laser light to cool and trap gases of neutral atoms. Laser-cooled atoms are then loaded into a magnetic trap, where they are compressed and further cooled. Finally, at some of the lowest temperatures achievable in a laboratory, the gas becomes quantum degenerate. Ultracold atom experiments capture the imagination of scientists and non-scientists alike, because we can see the quantum world with an ordinary camera. Degenerate gases can act as simulators of technologically relevant materials such as high-temperature superconductors. Eventually the many-body physics we learn with cold atoms may address open questions about these quantum materials. In our lab, we  trap two species (Rubidium 87, a boson, and Potassium 40, a fermion) with a microscopic "chip" trap. We use the Bose gas as a quantum "ice cube" to cool the Fermi gas. The strong confinement created in the chip trap leads to sympathetic cooling rates approximately ten times faster than typical experiments with Fermi gases. We have also shown that the same strong confinement leads to one of the highest efficiency evaporative cooling paths to Bose-Einstein condensation. Over the next five years, we plan to study the many-body physics of these quantum gases, including light scattering properties of cold fermions, non-harmonic traps, and the physics of Bose-Fermi mixtures.