Institut für Quantenoptik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
Phys Rev Lett. 2010 May 14;104(19):195303. doi: 10.1103/PhysRevLett.104.195303. Epub 2010 May 12.
Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 87Rb condensate. Interatomic interactions lead to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter.
真空涨落的参数放大在现代量子光学中至关重要，它可以实现压缩和纠缠的产生。我们使用自旋 F=287Rb 凝聚态展示了物质波真空涨落的参数放大。原子间相互作用导致初始 mF=0 凝聚态中关联的 mF=±1 对的产生，mF≠0 时，该凝聚态充当真空态。尽管从纯 mF=0 凝聚态中产生这种对理想情况下是由真空涨落触发的，但不可避免的虚假初始 mF=±1 原子会诱导经典种子，该种子可能成为主要触发机制。我们表明，在足够强的磁场下，对经典种子的产生不敏感，这证明了真空涨落的主导作用。因此，所提出的系统为生成非经典物质态提供了一条直接途径。
