An ultracold high-density sample of rovibronic ground-state molecules in an optical lattice
An ultracold high-density sample of rovibronic ground-state molecules in an optical lattice
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DOI：
10.1038/nphys1533
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发表时间：
2010-04-01
期刊：
影响因子：
19.6
通讯作者：
Naegerl, Hanns-Christoph
中科院分区：
文献类型：
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作者：
Danzl, Johann G.;Mark, Manfred J.;Naegerl, Hanns-Christoph
在单量子态水平上控制分子的所有内部和外部自由度将使一系列物理和化学的基础研究成为可能(1，2)。特别是，在超低温和高数密度下的基态分子样本将促进新的量子气体研究(3)和未来在量子信息科学中的应用(4)。然而，分子样品的高相空间密度并不容易获得，因为缺乏有效的冷却技术，如激光冷却。在这里，我们产生了一个超冷和致密的分子样品，它处于振荡子基态的单个超精细能级，每个分子分别被捕获在光学晶格势垒的运动基态中。从零温度原子Mott绝缘态(5)和优化的双位占有率(6)开始，弱束缚二聚体分子在Feshbach共振(7)上有效地缔合，然后通过受激四光子过程以50%的效率转移到振荡子基态。我们的结果向基态分子的玻色-爱因斯坦凝聚迈出了关键的一步，当适当地推广到极性异核分子时，偶极量子气相在光学晶格中的实现(8-10)。
Control over all internal and external degrees of freedom of molecules at the level of single quantum states will enable a series of fundamental studies in physics and chemistry(1,2). In particular, samples of ground-state molecules at ultralow temperatures and high number densities will facilitate new quantum-gas studies(3) and future applications in quantum information science(4). However, high phase-space densities for molecular samples are not readily attainable because efficient cooling techniques such as laser cooling are lacking. Here we produce an ultracold and dense sample of molecules in a single hyperfine level of the rovibronic ground state with each molecule individually trapped in the motional ground state of an optical lattice well. Starting from a zero-temperature atomic Mott-insulator state(5) with optimized double-site occupancy(6), weakly bound dimer molecules are efficiently associated on a Feshbach resonance(7) and subsequently transferred to the rovibronic ground state by a stimulated four-photon process with >50% efficiency. The molecules are trapped in the lattice and have a lifetime of 8 s. Our results present a crucial step towards Bose-Einstein condensation of ground-state molecules and, when suitably generalized to polar heteronuclear molecules, the realization of dipolar quantum-gas phases in optical lattices(8-10).